Geofoam Applications in the Design and Construction of Highway Embankments (2004)

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9-1 CHAPTER 9 GEOFOAM MQC/MQA Contents Introduction...................................................................................................................................9-3 Definitions ....................................................................................................................................9-3 Basis of the Provisional Standard .................................................................................................9-5 Overview..................................................................................................................................9-5 Problems with Current Standards ............................................................................................9-5 Key Technical Attributes of EPS-Block Geofoam Affecting Design......................................9-7 Philosophy Incorporated in the Provisional Standard..............................................................9-8 Proposed EPS Material Designation and Minimum Allowable Values of MQC/MQA Parameters................................................................................................................................9-9 MQC/MQA Test Requirements ..................................................................................................9-12 Overview................................................................................................................................9-12 Relevant Aspects of EPS-Block Geofoam for MQC/MQA Testing......................................9-12 Introduction.......................................................................................................................9-12 Flammability .....................................................................................................................9-12 Density ..............................................................................................................................9-12 Pre-Puff Quality and Fusion During Molding ..................................................................9-13 Seasoning ..........................................................................................................................9-13 Test Protocols .......................................................................................................................9-14 Record Keeping ................................................................................................................9-14 Sampling ...........................................................................................................................9-15 Testing ..............................................................................................................................9-18

9-2 Basis of the Proposed Manufacturing Quality Control (MQC) and Manufacturing Quality Assurance (MQA) Procedure......................................................................................................9-18 Overview................................................................................................................................9-18 Philosophy Incorporated in the MQC/MQA Procedure.........................................................9-20 Product Manufacturing Quality Control (MQC) Requirements .................................................9-22 Overview................................................................................................................................9-22 MQC Parameters to be Measured ..........................................................................................9-24 Allowable Raw Material ........................................................................................................9-24 Flame-Retardant Requirements .............................................................................................9-24 Seasoning Requirements........................................................................................................9-24 Dimensional Tolerances.........................................................................................................9-25 Product Manufacturing Quality Assurance (MQA) Requirements.............................................9-26 Overview................................................................................................................................9-26 Phase I....................................................................................................................................9-29 For All Molders...............................................................................................................9-29 Molders with Third-Party Certification ............................................................................9-30 Molders without Third-Party Certification .......................................................................9-30 Phase II ..................................................................................................................................9-30 Molders with Third-Party Certification ............................................................................9-32 Molders without Third-Party Certification .......................................................................9-34 Product Shipment........................................................................................................................9-35 Summary.....................................................................................................................................9-35 References...................................................................................................................................9-37 Figures ........................................................................................................................................9-38 Tables..........................................................................................................................................9-43 ______________________________________________________________________________

9-3 INTRODUCTION One of the overall objectives of NCHRP Project 24-11 was to develop a standard in the American Association of State Highway and Transportation Officials (AASHTO) format to optimize usage and performance for expanded polystyrene (EPS) - block geofoam as lightweight fill in road embankments. The proposed design methodology incorporated in the design guideline is based on the assumption that the EPS-block geofoam meets a set of minimum material and construction criteria. Therefore, a complementary provisional standard was developed. The provisional standard, which is included in Appendix C, is a combined material, product, and construction standard covering block-molded EPS for use as lightweight fill in road embankments and related bridge approach fills on soft ground. The standard is intended to be used to create a project-specific specification in conjunction with the recommended design guideline included in Appendix B. The basis for the provisional standard is initially presented followed by a discussion of its key features, which include the proposed EPS material designation system, the minimum allowable values of manufacturing quality control (MQC) and manufacturing quality assurance (MQA) parameters, and the MQC/MQA test requirements. The primary components of the provisional standard include the product MQC, MQA, shipment, and the construction quality requirements. The product MQC, MQA, and shipment requirements are presented herein. The construction quality requirements, e.g. construction quality control (CQC) and construction quality assurance (CQA) requirements, are presented in Chapter 8 (Geofoam Construction Practices). DEFINITIONS Quality in both manufactured products and services is an important issue throughout society and thus is an issue raised in this report. It is useful to state the definitions of two quality concepts and two quality aspects related to engineered construction used in this report. There are two general concepts related to manufactured products and services:

9-4 • Quality control (QC) refers to those actions taken by a product manufacturer or service provider to ensure that the final product or service meets certain minimum criteria. For engineered construction, these criteria are established by specifications produced by the design engineer for a particular project. These specifications may incorporate via reference standards established by some recognized organization such as AASHTO, the American Society for Testing and Materials (ASTM), or the Geosynthetic Institute (GSI). • Quality assurance (QA) refers to actions taken by some agency other than the manufacturer or service provider to independently verify the product or service quality. The QA agency may be the owner (e.g. a state DOT), the owner's representative (typically a consulting engineering firm), or any one of several companies that provide this service for manufactured products. QA may be provided on either a project-specific or ongoing basis. There are typically two aspects of both QC and QA in engineered construction: • Manufacturing quality control (MQC) and manufacturing quality assurance (MQA) which apply to manufactured products used on a given project that are delivered to the site more or less in a condition for direct use. Therefore, this would apply to the EPS blocks as used for geofoam because they are manufactured in a dedicated offsite plant, not at the project site. • Construction quality control (CQC) and construction quality assurance (CQA) which apply to the manner in which various materials and products are handled, stored, and placed at a project site by a construction contractor. Thus, this covers the manner in which the EPS-block geofoam is stored, handled, and placed at the project site. The distinctions between manufacturing and construction are important not only for the obvious division of responsibility but also because MQA and CQA can be handled in different ways. CQA must be performed on site at the time of construction. However, with any manufactured product there is always the alternative to pre-qualify product quality prior to

9-5 delivery to a project site as opposed to performing MQA once the material is delivered on site. As a simple yet common example to illustrate this, structural steel is generally accepted on site based on mill certificates or similar paperwork. Rarely would samples be cut on site from the steel and sent to a laboratory where specimens prepared from these samples would be tested for yield strength, etc. The importance of MQA for manufactured material is emphasized here because it is a significant issue with regard to MQA of EPS-block geofoam. BASIS OF THE PROVISIONAL STANDARD Overview In developing the recommended standards for future practice, problems related to the current use of existing standards were evaluated and reviewed herein. Because standards should complement the design methodology, the main technical attributes for the use of EPS-block geofoam as lightweight fill in road construction are considered so the requirements of the recommended standards are understood. Problems With Current Standards Currently, ASTM Standard C 578 (1) is the primary standard utilized in practice when developing a material specification for EPS-block geofoam. The standard was written primarily for the use of cellular polystyrene (both EPS and extruded polystyrene (XPS)) in above-ground, non-load-bearing thermal insulation applications and not lightweight fill applications. Therefore, the overall basis of the ASTM C 578 standard may not be applicable nor sufficient for load- bearing geofoam applications. The overall quality of block-molded EPS is more critical in lightweight fill applications than other applications because no other application has such significant load-bearing requirements. Two problems related to the use of ASTM Standard C 578 have emerged. The first problem is the tendency by EPS block molders to use as much regrind (recycled) material and to reduce the amount of virgin expandable polystyrene raw material to make the EPS-block geofoam blocks less costly and more cost competitive with other soft ground

9-6 treatment alternatives. The percentage of in-plant regrind and post-consumer recycled material and how it is fused into blocks may have varying affects on the mechanical properties (2,3) and on the time-dependent (creep) behavior of block-molded EPS. For example, tests have revealed that EPS with an average density of the order of 16 kg/m3 (1 lbf/ft3) had virtually the same compressive strength with up to 50 percent regrind content yet the initial tangent Young's modulus was reduced by a factor of approximately two between samples with no regrind and 50 percent regrind (4). Therefore, it is recommended that MQC/MQA compression tests also include reporting of the elastic limit stress and initial tangent Young's modulus to more accurately measure the impact of regrind content on the stress-strain behavior. The elastic limit stress is defined as the compressive stress at 1 percent strain as measured in a standard rapid-loading test (5). The slope of the initial (approximately) linear portion of the stress-strain relation is defined as the initial tangent Young’s modulus. Additionally, the flexural strength test is a useful MQC/MQA test in conjunction with compressive strength tests to evaluate pre-puff and fusion quality, especially when regrind material is used (2,3). The second problem is the tendency of the EPS industry to misinterpret the ASTM Standard C 578 density requirements. The standard only states minimum acceptable material properties (including density) of specimens cut from a block for the five standard grades of block- molded EPS covered by that standard. However, the standard is sometimes misinterpreted by the EPS industry to apply to a whole block instead of a specimen cut from a block. For example, if a customer specifies EPS with an average density of 20 kg/m3 (1.25 lbf/ft3), ASTM C 578 allows any particular specimen cut from a block tested for MQC/MQA purposes to have a density as low as 18 kg/m3 (1.15 lbf/ft3) which is approximately 10 percent less. It appears that the logic for this is related to the inherent density gradients (variations) that occur within block-molded EPS. It is entirely possible for a block of EPS that has an overall density of 20 kg/m3 (1.25 lbf/ft3) to have portions within that block of somewhat lower and higher density. Therefore, it appears that ASTM Standard C 578 was written to accommodate the inherent material variations that occur

9-7 within an EPS block. Molders in the U.S. have sometimes misinterpreted ASTM Standard C 578 so that the lower bound density provided in the ASTM standard is applied to a whole block instead of a specimen. Thus, a block with an overall density as low as 18 kg/m3 (1.15 lbf/ft3) is sometimes incorrectly considered as complying with ASTM C 578 and thus acceptable. Note that a block with an overall density of 18 kg/m3 (1.15 lbf/ft3) would have portions with an even lower density. The lesson learned from this emerging problem is that the applicability of lower-bound property values for either a given test specimen versus a block as a whole needs to be explicitly specified because it has important ramifications in load bearing capacity applications. In summary, it is recommended herein that the standard be applied to a specimen cut from a block and not the entire block. These two emerging problems related to the current use of ASTM Standard C 578 appear to originate from a perception or attitude of EPS block molders that EPS blocks placed in the ground can be of relatively low quality compared to EPS used in above-ground construction. "It's only going be buried in the ground" is a paraphrased sentiment often heard in practice. Of course, the exact opposite is true. If the underlying foundation of any structure is substandard the probability of failure of the entire structure is increased. Therefore, in many ways the overall quality of block-molded EPS is more critical in lightweight fill applications than any other because no other application has such significant load-bearing requirements. A contributing factor to industry perceptions concerning quality is the fact that EPS block is simply more expensive than soil on a volume basis. Thus a frequent sentiment heard in the industry is that "I'm competing with dirt." As a result of these attitudes and contributing factors, there is an overall tendency to reduce the amount of virgin expandable polystyrene raw material used to make EPS- block geofoam. Thus, tactics such as trying to use as much regrind (recycled) material and mold to as low a density as possible are believed to be pervasive in U.S. industry at the present time. Key Technical Attributes of EPS-Block Geofoam Affecting Design

9-8 Standards must complement the design methodology so the necessary engineering properties are present in the geofoam. Therefore, in developing standards for future practice, two primary technical attributes included in the design methodology for EPS-block geofoam used as lightweight fill in road construction were considered. First, lightweight fills are composed of entire blocks of EPS. Thus the overall properties and behavior of an entire block are of primary importance. For an engineer to design with confidence, every block of EPS delivered to a project site must, as a whole have an average block density that equals or exceeds some value that was assumed in design and specified in the design documents. Second, the proposed design methodology incorporates in the provisional design guideline the need to stay within the elastic range of the EPS (which is governed by the elastic limit stress) to limit both creep and plastic deformations and the explicit calculation of initial deformations (which is influenced by the initial tangent Young's modulus). Compressive strength and flexural strength are useful MQC/MQA tests for evaluating pre-puff and fusion quality. Therefore, for an engineer to design with confidence, every block of EPS delivered to a project site must, as a whole, have some minimum values of elastic limit stress, initial tangent Young's modulus, compressive strength, and flexural strength to ensure overall block quality with regard to material stiffness and prepuff fusion. Although the elastic limit stress and initial tangent Young's modulus show approximately linear correlation with EPS density, assuming the material is of appropriate quality, experience indicates that density alone does not sufficiently define EPS quality especially if regrind is used. Philosophy Incorporated in the Provisional Standard The basic philosophy adopted in the development of the provisional standard is to utilize the standard densities in ASTM Standard C 578 and add provisions related to the properties and behavior of EPS block that are necessary for a load bearing capacity application. First, the overall properties and behavior of an entire block are of primary importance. Second, EPS-block geofoam density can be used as an index property to estimate some mechanical and thermal properties provided the EPS meets a set of minimum criteria. Third, the proposed design

9-9 methodology is based on maintaining the long-term compressive stresses below the elastic-limit stress (within the elastic range) to keep long-term compressive strains within acceptable levels to limit both creep and plastic deformations. Fourth, because ASTM Standard C 578 does not currently contain any requirements for material stiffness (initial tangent Young's modulus) and elastic limit stress, recommended values are given in the proposed standard for these parameters as well. The proposed standard specifies lower-bound properties, i.e., density, compressive strength, flexural strength, elastic limit stress, and initial tangent Young’s Modulus, for a given MQC/MQA test specimen, not a block as a whole. For example, the average density of an entire block must equal or exceed a density that is slightly (approximately 10 percent) greater than the minimum allowed for an individual test specimen. These minimum values of initial tangent Young's modulus and elastic limit stress are the ones used in analysis and design. Although utilizing minimum values of initial tangent Young's modulus and elastic limit stress based on test specimens is slightly conservative because the average stiffness and elastic limit stress of the block as a whole would be somewhat greater than these minimums, this conservatism is not unreasonable because it would ensure that no part of a block (where the density might be somewhat lower than the overall average) would become overstressed. PROPOSED EPS MATERIAL DESIGNATION AND MINIMUM ALLOWABLE VALUES OF MQC/MQA PARAMETERS To facilitate and unify future design and specification, a material designation system for EPS-block geofoam was developed. The system selected is being used in western Europe wherein EPS-block geofoam is called "EPSx" where "x" is either two or three integers defining the minimum elastic limit stress of the block as a whole in kilopascals. Thus construction documents (plans and specifications) would indicate, for example, "EPS50 geofoam". Note that this compact notation identifies both the geofoam material (EPS) as well as the minimum elastic limit stress (50 kPa, (1,000 lb/ft2)) which is the design value. Furthermore, a designer would know that initial

9-10 tangent Young's modulus for use in compression calculations is approximately 100 times this value, i.e. 5,000 kPa (100,000 lbs/ft2)). Table 9.1 shows the correlation between the proposed EPS-block geofoam designations and ASTM Standard C 578 material types. Also shown are the corresponding minimum allowable densities for every block as a whole and for any MQC/MQA test specimen trimmed from a block. The density values for each block as a whole are 10 percent greater than the minimum allowed for an individual test specimen. For a given material type, the dry density of each EPS block (as measured for the overall block as a whole) after a period of seasoning shall equal or exceed that shown in Table 9.1. The dry density shall be determined by measuring the mass of the entire block by weighing the block on a scale and dividing by the volume of the block. The volume is determined by obtaining dimensional measurements of the block in accordance with ASTM test method C 303 (6). The length and width should be measured in at least two locations approximately along lines A-B and C-D lines in Figure 9.1 for the width and lines A-D and B-C for the length. For blocks larger than 1 m2 (10.8 ft2) in area, an additional length or width measurement should be made for each additional meter (3.3 ft) increase in length or width over 1 m (3.3 ft) long. These measurements can be spaced approximately equally within the original measurement area defined by A, B, C, D. For blocks larger than 1 m2 (10.8 ft2) in area, there should also be an additional two thickness measurements for each additional square meter (10.8 ft2) in size. These thickness measurements would be spaced approximately equally within the original measurement area defined by A, B, C, D such as locations E and F. Figure 9.1 Procedure for obtaining dimensional measurements on full-size EPS blocks (6). Table 9.1. Correlation between Current ASTM and Proposed AASHTO EPS Material Designations. The minimum allowable values of the other design and quality control parameters are given in Table 9.2. Note that these are for individual test specimens and not the block as a whole. The compressive and flexural strength values were adopted from ASTM Standard C 578. The

9-11 elastic limit stress and initial tangent Young's modulus were developed from observed correlations with the minimum density values from individual test specimens also shown in Table 9.2. These values of elastic limit stress and initial tangent Young's modulus in Table 9.2 would be the values used in analysis and design. The minimum allowable values of the various material parameters corresponding to each AASHTO material type shown in Table 9.2 are to be obtained by testing specimens prepared from samples taken from actual blocks produced for the project for either MQC by the molder or MQA by the owner's agent. Table 9.2. Minimum Allowable Values of MQC/MQA Parameters for Individual Test Specimens. There are four main benefits to the proposed designation system. First, it decreases the importance of compressive strength and focuses on the most important aspect of block-molded EPS for load bearing capacity applications: the initial tangent Young’s modulus or small-strain load-carrying capability. The parameter of compressive strength for EPS-block geofoam materials is not the key design parameter in practice because the compressive strength of EPS is defined arbitrarily, EPS does not fail in the traditional sense of material rupture, and compressive strength does not provide any insight into the creep behavior. Second, the proposed standard parallels the proposed design methodology that maintains the long-term compressive stress below the elastic-limit stress. Third, the proposed designation system also decreases the relevance of density which can be a misleading indicator especially if regrind is used. Fourth, this designation system will allow manufacturers maximum flexibility because it does not proscribe how much regrind material they can use but simply holds them accountable to the small-strain load-carrying characteristics of the final material. However, the influence of regrind content on creep behavior is not yet well understood because of the lack of test data on EPS with varying quantities of regrind and thus the topic is a subject for future study.

9-12 MQC/MQA TEST REQUIREMENTS Overview The requirements of MQC/MQA testing are somewhat different from those for testing for analysis and design parameters that were discussed in Chapter 2 because explicit testing for certain geotechnically relevant parameters, such as creep, are rarely performed for routine projects. The basis for this is almost 30 years of experience with EPS-block geofoam as lightweight fill for road earthworks has demonstrated that acceptable and cost-effective designs can be developed by correlating EPS density with these engineering parameters. However, these correlations with density can only be used with confidence if certain minimum qualities, e.g., a limited amount of regrind, of the EPS are assured by MQC/MQA. An appropriate analogy is that knowledge of only the density or unit weight of a soil conveys limited information as to its geotechnically relevant properties. Additional information is required to be able to use even the simplest empirical correlations for site characterization. Relevant Aspects of EPS-Block Geofoam for MQC/MQA Testing Introduction MQC/MQA of block molded EPS for lightweight-fill geofoam applications should address the following issues: • Flammability. • Density. • Pre-puff quality and fusion during molding. • Seasoning. The reasons for each of these is discussed in detail in the following sections. Flammability

9-13 As discussed in Chapter 2, it is generally considered good practice in the U.S.A. to specify flame-retardant EPS for all geofoam applications. Density This is probably the single most useful index property of block-molded EPS. Thus, its determination is part of all physical testing performed on EPS. Pre-Puff Quality and Fusion During Molding The overall quality of EPS-block geofoam as a load-bearing material (reflected in its elastic limit stress and initial tangent Young's modulus) is strongly dependent on the quality of the pre-puff (overall chemistry and age of the original expandable polystyrene raw material); age of the pre puff; and percentage (if any) of in-plant regrind and post-consumer recycled material and how it is fused into blocks. Although the classical parameters of compressive and flexural strength are of no direct use in design, together they are useful MQC/MQA tests for evaluating pre-puff and fusion quality, especially when regrind material is used (2,3). MQC/MQA compression tests should also include reporting of the elastic limit stress and initial tangent Young's modulus in compression which together are the most important mechanical properties for design of EPS-block geofoam as lightweight fill. Experience (4) indicates that these design parameters can be significantly affected by the overall quality and molding fusion of pre-puff, and that the traditional MQC/MQA parameter of compressive strength does not adequately reflect these effects. Seasoning EPS should not be delivered to a project site until the residual blowing agent (which is likely to be pentane in the U.S.A.) has outgassed sufficiently so there is no possibility that it can collect in joints between blocks and pose a fire or explosion hazard. However, there has been no known research on how long is required to sufficiently outgas or season the EPS for raw material formulations and block sizes in current U.S. practice. This is also a topic for future study. However, based on available published information (7) as well as anecdotal information obtained

9-14 by personal communication with both resin suppliers and block molders in the U.S.A., the tentative recommendation for the seasoning time is a minimum of three days at normal ambient room temperature although this time might be shortened by storage at elevated temperatures (not all block molders are equipped for this). This three-day minimum is also based on the assumption that the EPS blocks will be stored with air space between blocks as well as positive air circulation (using fans) and ventilation (using roof vents) within the storage space. This is because EPS blowing agents such as pentane are heavier than air and will tend to pool at the ground surface unless actively mixed with air and vented. Test Protocols Record Keeping Every block of EPS delivered to a project site should contain markings sufficient for the supplier to be able to trace the manufacturing history of the block in addition to other markings that may be deemed useful for constructability (density, location for placement relative to some job-specific shop drawing, etc.). The use of a self-adhesive label and/or barcode label would seem efficient for this purpose. The original molder should maintain and be able to produce detailed manufacturing records for every EPS block. The recommended record keeping procedure incorporated in the standard is that each EPS block shall be labeled to indicate the name of the molder (if there is more than one supplying a given project), the date the block was molded, the mass of the entire block (in kilograms or pounds) as measured after a satisfactory period of seasoning as previously discussed, the dimensions of the block in millimetres or inches and the actual dry density/unit weight in kilograms per cubic metre or pounds per cubic foot. Additional markings using alphanumeric characters, colors and/or symbols shall be applied as necessary by the supplier to indicate the location of placement of each block relative to the shop drawing as well as the density of the block if multiple block densities are to be supplied for a given project. If multiple block densities

9-15 are to be supplied, the use of no marking shall be considered an acceptable marking for one of the densities as long as it is used for the lower (lowest) density EPS blocks supplied to the project. Sampling In-plant sampling of EPS blocks for MQC/MQA testing purposes should be similar to that suggested for post-delivery MQA sampling performed during Phase IIc MQA (See “Product MQA Requirements” section of this chapter and Table 9.3). Sampling of EPS block is typically performed by cutting samples from various locations of an EPS block perpendicular to the longitudinal axis of the block. Specimens for testing are then trimmed from these samples. The test specimens shall be seasoned and dry density, compressive strength, and flexural strength shall be measured as specified in ASTM C 578. The specimens used for compressive testing shall be cubic in shape with a 50 mm (2 in.) face width. The specimens used for flexural strength are typically rectangular with dimensions varying depending on the length of the support span of the loading system. Chapter 2 provides further testing information. Basic MQA sampling and testing of production blocks of EPS has traditionally been the primary, even only, MQA tool from the earliest use of EPS-block geofoam as lightweight fill for roadways. Therefore, most national and international design manuals contain explicit recommendations for MQA sampling and testing. However, it appears that all such recommendations published to date have evolved from one single source: the Norwegian Road Research Laboratory of the Directorate of Public Roads. Figures 9.2 (a) and 9.2 (b) illustrate the recommended locations and dimensions of samples and test specimens. Each specimen shown is tested for density and compressive strength (keep in mind that in Norway the atypical definition of compressive strength is the compressive stress at 5 percent strain, not 10 percent as most everywhere else, is used). It appears that the logic for this sampling and testing is based on the traditional assumptions that: • Compressive strength is the key EPS property for both design and quality, which is now known to be incorrect and potentially misleading.

9-16 • Compressive strength is linked primarily to EPS density, which is correct. • Density of block-molded EPS is always the least at the corners, edges, and sides of a block, which is now known not to be always correct. Therefore, the basic thrust of the Norwegian MQA plan is to sample and test only the presumed weakest portions of an EPS block. The only notable deviation from Norwegian practice is reflected in the relatively recent German national design manual (8,9). Figure 9.3 shows the location of samples and test specimens recommended in the German design manual. The significant variation from Norwegian practice is the addition of sampling at the center of a block. Specimens prepared from center samples are tested for density and flexural strength only. It appears that the overall logic for the sampling and testing is based on the same assumptions as outlined above for the Norwegian MQA plan plus the following additional assumptions: • Prepuff fusion is also an important product-quality parameter, which is correct. • Fusion quality is most easily tested by inducing flexural stress in a specimen as tensile normal stresses are the best check for fusion and flexure induces such stresses in one side of a test specimen, which is correct. • Fusion is always poorest at the center of an EPS block as it is the most difficult portion of the block for the steam introduced during block molding to reach, which is now known to be not always correct. (a) Sampling. (b) Compression test specimens. Figure 9.2. EPS block sampling and compression test specimens per NRRL guidelines (all dimensions in millimetres) (5). Figure 9.3. EPS block sampling and test specimens per German national design manual (8,9).

9-17 An assessment of the test protocols used to date indicates that current sampling and testing protocols are not keeping pace with the current state of knowledge. The specific reasons are: • The stiffness parameters of elastic limit stress and initial tangent Young's modulus must be tested. Compressive strength provides no reliable correlation with these design parameters. • With modern block molding equipment, the lowest density may not always occur at or near the exterior of the block as appears to be presumed in the Norwegian (5) and German (8,9) sampling guidelines. Neither will the poorest fusion (and flexural strength) always occur near the center as appears to be presumed in the German (8,9) sampling guidelines. • For the higher EPS densities (up to approximately 32 kg/m3 (2 lbf/ft3)) sometimes used in geofoam applications, the lowest density may not always occur at or near the exterior of the block. Neither will the poorest fusion (and flexural strength) always occur near the center. Consequently, an entirely new sampling and testing protocol is recommended herein for use in practice. The recommended block sampling procedures are shown in Figure 9.4 and are based on the following assumptions: • The gradients (variation) in both density and fusion within an EPS block tend to be predominantly within planes oriented perpendicular to the longitudinal axis of a block. Therefore, sampling and testing should focus on material variations in this plane. However, the qualitative distribution of these gradients (as done historically and reflected in the Norwegian and German design manuals) cannot be reliably assumed in advance. Therefore, test specimens must be prepared and

9-18 all necessary parameters (listed below) tested at each of the three locations (A. B and C) shown in Figure 9.4 to allow for any gradients in both density and fusion. • At each of the three locations (A, B and C) shown in Figure 9.4, the following parameters should be measured: (1) density, (2) elastic limit stress in compression, (3) initial tangent Young's modulus in compression, (4) compressive strength, and (5) flexural strength. The elastic limit stress in compression and the initial tangent Young's modulus in compression can be obtained during compressive strength testing. Thus, at each sampling location, it is recommended that one compressive strength test and one flexural strength test be performed. Note that second through fourth items are all measured in a single test. The actual number of specimens that can be cut at each sample location (A, B, and C) will depend on the thickness of the EPS block. • All test parameters at all locations must equal or exceed the minimum allowable values given previously in Table 9.2. Testing The testing protocols specified in ASTM Standard C 578 should be used with the additional requirements that the elastic-limit stress in compression and initial tangent Young's modulus in compression be measured, reported, and meet the minimum criteria given in Table 9.2. An axial strain rate of 10 percent per minute shall be used for the compressive strength tests. Both the elastic limit stress and initial tangent Young's modulus shall be determined in the same test used to measure compressive strength. Figure 9.4. Recommended block sampling and test specimens. BASIS OF THE PROPOSED MANUFACTURING QUALITY CONTROL (MQC) AND MANUFACTURING QUALITY ASSURANCE (MQA) PROCEDURE Overview

9-19 Manufacturing quality control (MQC) is internal actions taken by the manufacturer of a product (EPS block molder in this case). MQC can have two distinct components: • As a minimum, MQC consists of a series of policies and procedures that a manufacturer must establish beforehand so that the final material or product will meet or exceed some definable, measurable criteria. These criteria must, of course, be defined in advance by the organization who is ultimately responsible for accepting the material (which, for EPS-block geofoam, is generally the civil engineer acting on behalf of the project owner). For the sake of efficiency, it is generally desirable to use some established standards (AASHTO, ASTM, etc.) as the criteria. • MQC may also include the manufacturer's performing one or more tests on specimens prepared from samples taken from the final product. The purpose of these tests is to verify that the expected results have, in fact, been achieved. Generally these tests are the same as those used for MQA. Manufacturing quality assurance (MQA) must, by definition, be performed by an organization other than the manufacturer. This can take several contractual forms: • The MQA agent may be an independent organization retained by the manufacturer, usually on an ongoing as opposed to a project-specific basis. There are a number of business organizations such as Factory Mutual, RADCO, and Underwriters Laboratory (this alphabetical listing is intended to be illustrative and not necessarily complete) and others whose sole or primary business is providing what is generally called third-party certification of a myriad of manufactured products. It is important to note that, although these organizations are paid by the manufacturer for whom they are providing oversight, the presumption is that these organizations must protect their business reputation and, therefore, can be expected to remain objective.

9-20 • The MQA agent may be a company (typically a materials testing laboratory or geotechnical consulting firm in the case of EPS-block geofoam) hired by the purchaser of the product (generally a construction contractor in the case of EPS- block geofoam). The owner's engineer (who may or may not be the original designer) will generally review the MQA results in this case. • The MQA agent may be the owner's engineer (who may or may not be the original designer). The preferred contractual relationship of the MQA agent is a subject often debated in many areas of civil engineering not just geofoam. In any event, the function of the MQA agent is to review certain records maintained by the manufacturer and perform various tests on specimens prepared from samples taken from the manufactured product. Again, whether this is the product manufactured for the specific project in question or simply product judged to be representative is subject to debate. In summary, there are several aspects regarding manufacturing quality, MQA in particular, that are subject to debate. However, with regard to EPS-block geofoam it should be kept in mind that it is a product that is always manufactured in a controlled environment in a fixed plant dedicated to that purpose. Therefore, the MQC and MQA requirements specified should be consistent with those for similar manufactured products which include most other geosynthetics. Philosophy Incorporated in the MQC/MQA Procedure To begin the process of developing a meaningful MQC/MQA procedure, the properties of EPS-block geofoam that are critical to its use as lightweight fill in road applications were identified. These properties include: (1) The EPS should be flame-retardant; (2) Each block must be appropriately seasoned with respect to outgassing of the blowing agent (which will typically be pentane in the U.S.); (3) All blocks must meet the criteria for geometric tolerances with regard to both dimensional variation, orthogonality, and face warp; (4) The average density of each

9-21 block delivered for a given project must equal or exceed the specified minimum allowable given in Table 9.1; (5) The density of any test specimen prepared from a sample cut from a production block for a given project must equal or exceed the specified minimum allowable given in Table 9.2 (which will generally be approximately 10 percent less than the overall allowable minimum for an entire block); (6) The small-strain stiffness parameters used for design (elastic limit stress and initial tangent Young's modulus) must equal or exceed the specified minimum allowable given in Table 9.2; (7) The traditional quality control parameters of compressive and flexural strength must equal or exceed the specified minimum allowable given in Table 9.2. It appears that the optimal way to achieve these goals is to utilize a combination of quality control mechanisms implemented in two phases, one prior to shipment from the block molding plant and the other after delivery of blocks to the project site. In addition, there should be a two-tier system of MQA, one for molders with third-party certification and the other for those without third-party certification. Although third-party certification is not perfect, it clearly offers some level of quality assurance. Therefore, it is reasonable to treat EPS molders who subscribe to a recognized third-party certification agent and program differently than those who do not. Table 9.3 presents an overview of the two-phased system. Table 9.3. Proposed Manufacturing Quality Assurance (MQA) Procedure for EPS- Block Geofoam Used for the Function of Lightweight Fill in Road Embankments. The primary components of the provisional specification are the product manufacturing quality control (MQC) requirements, product manufacturing quality assurance (MQA) requirements, product shipment, and construction quality requirements to include construction quality control (CQC) and construction quality assurance (CQA) requirements. An overview of the manufacturing components is presented below with the construction quality requirements being presented in Chapter 8.

9-22 PRODUCT MANUFACTURING QUALITY CONTROL (MQC) REQUIREMENTS Overview There are numerous factors that affect the final quality of block-molded EPS, beginning with the source and age of the expandable polystyrene raw material used and ending with numerous aspects of the molding process. Because EPS has been manufactured for approximately 50 years, these various factors appear to be sufficiently documented and known in the industry. Therefore, as long as the desired quality of the final product is known (this would be specified by the project design engineer) a molder is able to select the required combination of manufacturing variables to produce the desired final product. Therefore, a molder's primary MQC plan is really a large set of manufacturing variables based on technical guidelines and experience known in the industry. In general, EPS block molders in the U.S.A. perform relatively little in-plant laboratory type testing of small specimens cut from samples taken from production blocks. About the only physical testing performed on the finished blocks on a routine basis is to weigh the entire block relatively soon after it is molded (some newer molds do this automatically). This allows a determination of the overall average density or unit weight of the block as the dimensions of the block are consistent and known beforehand. However, this immediate post-molding weight and density determination must be viewed with some caution because there will be condensed water vapor trapped within the block from the steam used in the molding process. There will also be some residual blowing agent gas (which is always denser than air) within the block. Taken together, it is not uncommon for the immediate post-molding density to be 10 percent to 20 percent greater than the true dry density of the EPS but decrease with seasoning time. However, the density of blocks made with vacuum cooling molds may increase with seasoning time. Therefore, three days of seasoning at normal ambient room temperatures may be required for the block density to stabilize (i.e. dry and outgas the residual blowing agent) and even that is

9-23 dependent on there being adequate air circulation between stored blocks and adequate positive exhaust ventilation within the area used to store blocks during post-molding seasoning. There is one issue that straddles the boundary between manufacturing and construction quality. It is primarily the responsibility of the molder (hence discussed in this section as an MQC issue) but is enforced by the construction inspection agent (so is also included under the discussion of CQA in Chapter 8). This is the issue of damage to EPS blocks during shipping. Typically, the selection of trucks used to ship EPS blocks (almost always a tractor-pulled trailer, but the trailer may either be flat bed or a closed box), the loading of these trucks and the manner in which the load is secured (important when flat-bed trailers are utilized) are all under the control of the EPS molder. Thus, responsibility for the as-delivered condition of the EPS blocks is largely controlled by the molder. This is an important issue to address and incorporate into manufacturing specifications as recent, anecdotal evidence indicates that block damage on EPS- block geofoam projects within the U.S.A. is not uncommon and is the source of on-site problems with block acceptance. The reason for the damage appears to be the preferred use of flat-bed trucks as EPS blocks used for lightweight fill have gotten longer with newer molding equipment placed on line during the 1990s. Because the very light EPS blocks must be securely and tightly strapped to prevent their movement during shipping, it is not uncommon for EPS blocks to arrive at the job site with numerous indentations of the edges along the sides of the blocks from the strapping as well with breakage at the end corners of the blocks. One shipping method that may be considered to minimize damage to the blocks is to use structural angles along the top edge of the exterior blocks that would accommodate the strapping. MQC is the primary responsibility of the molder. The MQC parameters are the same parameters that will be measured as part of manufacturing quality assurance (MQA) to be conducted by the owner's agent. In addition to the parameters to be measured during MQC, allowable raw material, flame retardant requirements, seasoning requirements, and EPS block dimensional tolerances are also subsequently addressed.

9-24 MQC Parameters To Be Measured Table 9.2 indicates the proposed material designations and the minimum allowable values of MQC/MQA parameters for individual test specimens. Allowable Raw Material The EPS-block geofoam shall consist entirely of expanded polystyrene. At the discretion of the molder, the EPS-block geofoam may consist of some mixture of virgin raw material (expandable polystyrene a.k.a. bead or resin) and recycled EPS (regrind). If regrind is to be used, this shall be identified by the molder as part of the Phase I MQA pre-certification process subsequently discussed. The source of the regrind (block-versus shape-molded EPS, in-plant versus post-consumer) should also be identified. Flame-Retardant Requirements Although the practice in some countries is to use normal or regular (non-flame-retardant) expandable polystyrene raw material for cost reasons, the recommended practice in the provisional specifications is to require the use of flame retardant EPS, which is currently the standard practice in the U.S. Thus, all EPS-block geofoam shall satisfy the product flammability requirements specified in ASTM C 578. Seasoning Requirements A flammability concern is the potential of ignition of residual blowing agent that outgasses after block placement and collects in the joints between blocks. Outgassing of post- molding residual blowing agent is addressed by requiring an adequate seasoning period prior to delivery of the EPS blocks to the project site. This issue has not been formally studied to date for blocks produced in the U.S.A. (seasoning time is affected by the exact formulation (pentane content) of the expandable polystyrene and block dimensions, among several other factors). Based on available published information (7) as well as anecdotal information obtained by personal communication with both resin suppliers and block molders in the U.S.A., an interim recommendation of three days (72 hours) at ambient room temperature (seasoning can be

9-25 accelerated by temporary storage within a heated room) is proposed prior to shipment and incorporated into the provisional standards. Seasoning is defined as storage in an area suitable for the intended purpose for a minimum of 72 hours after an EPS block is released from the mold. The molder may request a shortened seasoning period if the EPS blocks are seasoned within an appropriate heated storage space and the molder demonstrates to the satisfaction of the owner's agent that the alternative seasoning treatment produces block that equal or exceed the quality of the blocks subjected to the normal 72-hour seasoning period. Dimensional Tolerances Because of the various types of molding equipment currently in use in the U.S., different dimensional variations may occur between blocks produced by different molders. The dimensional tolerances of EPS blocks used for the function of lightweight fill affects construction through the ability of the blocks to fit together with minimal gaps and maintain a planar surface as subsequent layers of blocks are placed. The provisional standard incorporates physical and dimensional tolerances used in Norway which are based on decades of experience. Dimensional tolerances are defined by three geometric variables. (1) Variations in linear dimensions: The thickness, width and length dimensions of an EPS block are defined herein as the minimum, intermediate and maximum overall dimensions of the block, respectively, as measured along a block face. These dimensions of each block shall not deviate from the theoretical dimensions by more than ±0.5 percent. (2) Deviation from perpendicularity of block faces: The corner or edge formed by any two faces of an EPS block shall be perpendicular, i.e. form an angle of 90 degrees. The deviation of any face of the block from a theoretical perpendicular plane shall not exceed 3 mm (0.12 in.) over a distance of 500 mm (20 in.). (3) Overall warp of block faces: Any one face of a block shall not deviate from planarity by more than 5 mm (0.2 in.) when measured using a straightedge with a length of 3 m (9.8 ft).

9-26 PRODUCT MANUFACTURING QUALITY ASSURANCE (MQA) REQUIREMENTS Overview The traditional approach taken for MQA of EPS-block geofoam in lightweight fill applications is to rely solely on post-delivery block sampling and testing by the owner's testing laboratory or engineer. It is believed that one significant reason for this is the historical evolution of EPS-block geofoam in places where, at the time, pre-delivery MQA alternatives such as third- party certification were unavailable. Thus, MQA handled in the traditional manner also straddles the boundary between manufacturing and construction as the sampling and testing for manufactured quality is handled as a construction activity. At the present time, MQA for geofoam (pre-delivery, post-delivery or some combination of the two) is still evolving in U.S. practice. This is due to several reasons, each of which has positive and negative aspects: • Many EPS block molders in the U.S.A. now subscribe to third-party certification by an inspection organization dedicated to providing that service. However, as it exists normally, such certification does not appear to include specific testing of products destined for a specific project. Rather, certification is based on an assessment of management of the overall manufacturing operation, presumably with occasional, random spot checks by physical testing. Thus, civil engineers have been reluctant in some cases to accept third-party certification as the sole MQA because it is not project specific. • Third-party certification is typically set up for compliance with existing standards, most notably ASTM Standard C 578. However, as discussed previously, geofoam-grade block-molded EPS has requirements for material stiffness that are not in ASTM Standard C 578 or any other known standard at the present time. Therefore, third-party certification as it typically exists currently

9-27 for block-molded EPS may not be sufficiently stringent for lightweight fill applications. • There is recent project experience in the U.S.A. to indicate that third-party certification is not foolproof. Specifically, independent post-delivery testing by at least two state DOTs suggests that EPS-block geofoam of overall quality not meeting specifications has been delivered to projects. While such anecdotal information may not constitute conclusive scientific proof, informal sharing and transmission of such information among civil engineers has added to the wariness of relying solely on third-party certification as it exists now. • EPS-block geofoam is still a novel construction material to most civil engineers in the U.S.A. Therefore, there is a reluctance to accept this material without at least some post-delivery testing, especially in view of the fact that this is the historical method for performing MQA for EPS-block geofoam. • EPS-block geofoam is still a novel construction material to most state DOTs in the U.S.A. In addition, such government agencies, as custodians of the public trust and safety, are historically more cautious than the private sector when it comes to accepting and using new technology. Therefore, there is a reluctance to accept this material without at least some post-delivery testing, especially in view of the fact that this is the historical method for performing MQA for EPS-block geofoam. • Post-delivery testing can be time consuming and delay geofoam placement on site. This is an important issue because the EPS blocks are usually placed directly from the delivery truck. Thus, it would be time consuming and costly to exhume a group of blocks placed days or even weeks earlier if the test results were unacceptable. However, this would have to be done if necessary.

9-28 Resolution of the above issues and problems with both pre- and post-delivery MQA practice as they currently exist to develop an MQA strategy that balances both the technical need to verify product quality and the associated cost will require an evolutionary process that includes input from and dialog between both EPS molders, their customers (usually a construction contractor), the design engineer, and the ultimate owner. A goal of this report is to assist in initiating such a dialog by clarifying the relevant issues to be addressed by MQA and incorporating these into the design guidelines and specification that are part of this report. It is expected that the design documents included with this report will see further evolutionary modification in the future. The purpose of MQA of the EPS-block geofoam product is to verify the molder's MQC procedures. The owner's agent will have primary responsibility for all MQA unless the owner notifies the contractor otherwise. The proposed MQA program consists of two phases. Phase I MQA consists of pre-certification of the molder and shall be conducted prior to shipment of any EPS blocks to the project site. Phase II MQA shall be conducted as the EPS blocks are delivered to the project site. Phase I and all four subphases of Phase II MQA are performed regardless of whether or not the EPS molder has third-party certification. However, there is a difference in terms of the extent to which MQA is conducted. It should be noted that procedures to be followed once the blocks arrive at the construction site are also considered part of CQA. Thus, the owner’s CQA agent will also be performing MQA. A truckload of EPS blocks is intended to mean either a full length box- or flat-bed trailer of typical dimensions, i.e., approximately 12 metres (40 ft) or more in length, fully loaded with EPS blocks. The volume of EPS in such a truckload would typically be on the order of 50 to 100 m3 (65 to 130 yd3). Each MQA phase is discussed below and as is shown in Table 9.3 a two-tier MQA system, one for molders with third-party certification and one for those without, is recommended. The following sections provide more detail on the entries in Table 9.3.

9-29 Phase I Phase I consists of pre-certification of the molder and is performed prior to shipment of EPS blocks to the project site. The purpose of the pre-certification procedure is to verify that the molder has the ability to provide EPS-block geofoam of the desired quality. The proposed Phase I MQA steps that are required prior to shipment to the project site are as follows. For All Molders • If the designer has made the block layout the responsibility of the molder, the required shop drawings showing the proposed block layout must be prepared and submitted to the designated representative of the owner for approval prior to shipping any blocks. The required minimum time for shop drawing submittal and acceptance must be specified in the project design documents and be in accordance with owner requirements. • If the designer has assumed responsibility for the block layout, shop drawings are not required unless changes to the block layout shown in the contract documents are desired by the block molder and/or construction contractor. This should be handled as any other change order request initiated by a contractor. • Each block delivered to the project site should be labeled with the following minimum information: ƒ if multiple plants and/or molders are supplying a given project, the name of the molder and plant location; ƒ date block was molded; ƒ block dimensions; ƒ actual block mass/weight (in kilograms or pounds) and density/unit weight (in kilograms per cubic metre or pounds per cubic foot), as determined by weighing after the required period of seasoning; and

9-30 ƒ when multiple densities are to be used on the same project, an easily visible color marking system should be used to distinguish between blocks of different density (no marking can be used as one of the requisite "markings" but it must always be for the lower/lowest density). It is suggested that molders develop and print a simple self-adhesive label that contains blank spaces in which this information can efficiently be entered at the molding plant. Molders With Third-Party Certification • A molder with third-party certification should, prior to shipping any blocks for a project, be required to: ƒ identify the organization providing this service, ƒ provide detailed information as to the procedures and tests used by this organization, and ƒ provide written certification that all EPS blocks supplied to the project will meet the requirements specified in the project specifications. Molders Without Third-Party Certification • A molder without third-party certification should, prior to shipping any blocks for a project, be required to submit a letter stating that all EPS blocks supplied for the project are warranteed to meet specifications requirements. They should also be requested to describe what MQC measures they employ, e.g. in-plant testing, etc. In addition, at the owner's discretion the molder should be required to submit a pre-production block to demonstrate that they have the ability to provide product of the desired quality. Phase II

9-31 The procedures to be followed once the blocks arrive at the construction site are considered part of CQA and thus are considered in Chapter 8. However, construction is also when Phase II of MQA is executed by the owner's CQA agent. Phase II MQA has four subphases: • The first subphase (Phase IIa) consists of verification of the physical condition of the EPS blocks and index properties (age and density) of the EPS. The CQA agent should inventory and inspect each and every block as it arrives on site to check for physical damage during shipment and to verify age and density requirements based on the required factory applied labeling. Any block with significant physical damage or density not meeting the minimum specified in Table 9.1 should be rejected. • The second subphase (Phase IIb) consists of confirming key physical and index properties of the overall block and EPS respectively. Suggested guidelines for how many blocks to check are given subsequently. At the CQA agent's discretion, additional blocks should be checked, especially at the beginning of a project and/or if the EPS molder does not have third-party certification. Additionally, at the CQA agent’s discretion, representative blocks from each manufacturing day can be checked. The dimensions and warp of blocks should be checked on site by the CQA agent and compared to specified requirements. The weight indicated on the label should be checked using a commercial scale, recently certified with regard to its calibration, provided by the construction contractor for this purpose. It should be possible to make these measurements in a relatively short period of time so as not to delay on-site handling and use of the blocks. • The third subphase (Phase IIc) consists of confirming the EPS engineering design parameters related to stiffness as well as the quality control strength parameters. Specifically, the CQA agent should sample and test the EPS for compliance with

9-32 specified requirements with respect to the elastic limit stress, initial tangent Young's modulus, compressive strength, and flexural strength. Figure 9.4 provides a basic plan for sampling location. At the present time the only reliable testing is conventional laboratory testing in accordance with ASTM Standard C 578 which, at best, will take a few days to accomplish. However, ASTM Standard C 578 should be augmented to include measurement of the elastic-limit stress and initial tangent Young’s modulus in compression using an axial strain rate of 10 percent per minute. The elastic limit stress in compression and the initial tangent Young's modulus in compression can be obtained during compressive strength testing. Thus, at each sampling location, it is recommended that one compressive strength test and one flexural strength test be performed. As shown in Figure 9.4, three sampling locations are recommended. Therefore, for each block to be tested, a minimum of three compressive strength tests and three flexural strength tests are recommended. A high priority for the future should be research and development of some type of device for testing the stiffness of EPS blocks at the project site (this is discussed further in Chapter 13 of this report). • The fourth and final subphase (Phase IId) consists of recording where blocks are placed to the greatest extent possible by marking copies of the drawings that show the block layout (either shop drawings or design drawings as appropriate). The purpose of this is to assist in locating blocks that may need to be exhumed at a later date if some question as to manufacturing quality should arise. All four subphases of Phase II MQA are conducted regardless of whether or not the EPS molder has third-party certification. However, there is a difference in terms of the extent to which Phase II MQA is conducted. Molders With Third-Party Certification

9-33 For molders with previously approved third-party certification, the following process is recommended for the subphases of Phase II MQA: • Phase IIa should be applied to each truckload. • Phase IIb should be applied to each truckload. Initially, only one block per load should be selected and checked by the CQA agent. If the selected block meets specification with respect to its size and shape, and the mass agrees with that marked on the block, no further checking of the load for these parameters is required and the shipment is approved conditionally until the Phase IIc test results verify that the blocks meet specifications. If the block does not meet specification, with respect to its size, shape, and mass, then other blocks in the truckload should be checked and none used until the additional checking has determined what blocks are unsatisfactory. The number of additional blocks to be tested is to be determined by the CQA agent. At the completion of this subphase, the construction contractor should be conditionally allowed to proceed with installing blocks. However, this should be done with the understanding that EPS blocks may have to be exhumed and removed at a later date if Phase IIc testing indicates problems. • Phase IIc sampling and testing should be done on an ongoing basis during the course of the project. However, the owner and the owner's CQA agent can exercise considerable judgement here. For example, they may choose to do testing only at the beginning of a project to verify that the EPS molder's MQC and third-party certification is achieving the desired goals or even omit testing entirely on a small project. • Phase IId as-built record keeping should always be performed.

9-34 Molders Without Third-Party Certification For EPS molders without third-party certification, the on-site (Phase II) MQA is more critical than for those molders with third-party certification: • Phase IIa should be applied to each truckload. • Phase IIb should be applied to each truckload. For the first load delivered to a project, each block on that load should be checked by the CQA agent. For subsequent loads, at least one block per load should be selected and checked. • Phase IIc sampling and testing should be applied to all projects, regardless of size, and throughout the entire duration of the project. It is suggested that no blocks be placed until the first truckload for the project has been sampled and tested. For each density of EPS used on a project, at least one block will be selected for sampling from the first truckload of EPS blocks of that density delivered to the job site. Additional blocks may be selected for sampling during the course of the project at the discretion of the owner's agent at a rate of sampling not to exceed one sample for every 250 m3 (325 yd3) of EPS delivered. Portions of sampled blocks that are otherwise acceptable can be used as desired by the contractor. For subsequent truckloads, the construction contractor should be allowed to place blocks while sampling and testing is going on with the understanding that it may be necessary to exhume and remove blocks not meeting specifications. The owner's agent will make every reasonable effort to conduct the laboratory testing expeditiously. If unsatisfactory test results are obtained, the contractor may be directed to remove potentially defective EPS blocks and replace them with blocks of acceptable quality at no additional expense to the owner. • Phase IId as-built record keeping should always be done.

9-35 PRODUCT SHIPMENT Prior to delivery of any EPS-block geofoam to the project site, a meeting shall be held between, as a minimum, the owner's agent and contractor. The supplier and/or molder of the EPS- block geofoam may also attend at the contractor's discretion to facilitate answering any questions. The purpose of this meeting shall be to review the Phase I MQA results and discuss Phase II MQA as well as other aspects of construction to ensure that all parties are familiar with the requirements of the specification. After this meeting, the contractor can begin on-site receipt, storage (if desired), and placement of the EPS-block geofoam. The molder should label each block delivered to the project site with the following minimum information: if multiple plants and/or molders are supplying a given project, the name of the molder and plant location; the date that the block was molded; the mass/weight of the entire block (in kilograms or pounds) as measured after a satisfactory period of seasoning; the actual dry density/unit weight (in kilograms per cubic metre or pounds per cubic foot); the dimensions of the blocks (in millimetres or inches); and when multiple densities are to be used on the same project, an adequate marking system should be used to identify blocks of different density. If the EPS blocks are to be stockpiled at the project site until placement, a secure storage area shall be designated for this purpose. Additional block handling and storage requirements are provided as part of CQC/CQA in Chapter 8. SUMMARY The provisional standard, which is included in Appendix C, is a combined material, product, and construction standard covering block-molded expanded polystyrene (EPS) for use as lightweight fill in road embankments and related bridge approach fills on soft ground. The provisional standard is intended to be used in conjunction with the design guideline included in Appendix B. The primary components of the provisional standard include the product manufacturing quality control (MQC) requirements, product manufacturing quality assurance (MQA)

9-36 requirements, product shipment, and construction quality requirements to include construction quality control (CQC) and construction quality assurance (CQA) requirements. The key features of the provisional standard include the proposed EPS material designation system shown in Table 9.1 and the minimum allowable values of MQC/MQA parameters for individual specimens and not the entire block shown in Table 9.2. The parameters are to be measured using ASTM Standard C 578 and an axial strain rate of 10 percent. A new sampling protocol is shown in Figure 9.4 and a new two-phased MQA procedure is presented in Table 9.3. Phase I of the MQA procedure is to be performed prior to shipment of EPS blocks to the project site and Phase II is to be performed as the EPS blocks are delivered to the project site. Another key aspect of the proposed MQA procedure is the implementation of a two-tier MQA system, one for molders with third-party certification and the other for those without. Standards always require review and possible modification when developing project- specific specifications. For example, the recommended minimum seasoning requirement of 72 hours may create problems on projects that are relatively large in size and/or have tight delivery schedules. Therefore, project-specific decisions might be necessary to relax this seasoning requirement. Experience indicates that this may be permissible to expedite construction work provided that appropriate safety precautions for fire safety and worker safety are implemented. The requirements for physical and dimensional tolerances are known to have been relaxed on a project-specific basis in the U.S. for cost reasons. There has been no systematic study of how much deviation from normally accepted practice is acceptable. Thus owners who, either directly or through their representatives, accept blocks with tolerances that exceed those normally used must accept a greater, but incalculable, uncertainty with regard to overall final performance of the fill. The standard presented in this chapter and included in Appendix C should facilitate the use of EPS-block geofoam in civil engineering projects by providing engineers with a combined material, product, and construction standard for use in developing a project-specific specification.

9-37 However, there are issues and problems, both real and perceived, with both pre- and post-delivery MQA practice as they currently exist. Resolution of these issues and problems will require an evolutionary process that includes input from and dialog between both EPS molders, their customers (usually a construction contractor), the design engineer, and the ultimate owner. A goal of this report is to assist in initiating such a dialog by presenting relevant issues to be addressed by MQA and incorporating these into the provisional design guideline and standard that are part of the report. It is expected that the provisional standard will see further evolutionary modification in the future. REFERENCES 1. ASTM D 578-95, “Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation.” Vol. 04.06, American Society for Testing and Materials, West Conshohocken, PA (1999) . 2. Bartlett, P. A., “Expanded Polystyrene Scrap Recovery & Recycling.” ARCO Chemical Company (undated) . 3. Bartlett, P. A., “Letter report to unnamed customer 11 September.” ARCO Chemical Company, Newtown Square, PA (1986) . 4. Horvath, J. S., Personal Communication. 5. Horvath, J. S., Geofoam Geosynthetic, , Horvath Engineering, P.C., Scarsdale, NY (1995) 229 pp. 6. ASTM C 303-98, “Standard Test Method for Dimensions and Density of Preformed Block and Board-Type Thermal Insulation.” Vol. 04.06, American Society for Testing and Materials, West Conshohocken, PA (2001) . 7. Coughanour, R. B., “Pentane Issue.” Presentation at the 16th Annual SPI Expanded Polystyrene Division Conference, San Diego, CA, (1988) . 8. “Merkblatt für die Verwendung von EPS-Hartschaumstoffen beim Bau von Straßendämmen.” Forschungsgesellschaft für Straßen- und Verkehrswesen, Arbeitsgruppe Erd- und Grundbau, Köln, Deutschland (1995) 27 pp. 9. “Code of Practice; Using Expanded Polystyrene for the Construction of Road Embankments.” BASF AG, Ludwigshafen, Germany (1995) 14 pp.

FIGURE 9.1 PROJ 24-11.doc 9-38

FIGURE 9.2A PROJ 24-11.doc 9-39

FIGURE 9.2B PROJ 24-11.doc 9-40

FIGURE 9.3 PROJ 24-11.doc 9-41

FIGURE 9.4 PROJ 24-11.doc 9-42

TABLE 9.1 PROJ 24-11.doc Material Designation Minimum Allowable Density, kg/m3 (lbf/ft3) AASHTO (proposed) ASTM C 578 Each Block as a Whole Any Test MQC/MQA Specimen EPS40 I 16 (1.0) 15 (0.90) EPS50 VIII 20 (1.25) 18 (1.15) EPS70 II 24 (1.5) 22 (1.35) EPS100 IX 32 (2.0) 29 (1.80) 9-43

TABLE 9.2 PROJ 24-11.doc Material Designation Dry Density, kg/m3 (lbf/ft3) Compressive Strength, kPa (lbs/in²) Flexural Strength, kPa (lbs/in²) Elastic Limit Stress, kPa (lbs/in²) Initial Tangent Young's Modulus, MPa (lbs/in²) EPS40 15 (0.90) 69 (10) 173 (25) 40 (5.8) 4 (580) EPS50 18 (1.15) 90 (13) 208 (30) 50 (7.2) 5 (725) EPS70 22 (1.35) 104 (15) 276 (40) 70 (10.1) 7 (1015) EPS100 29 (1.80) 173 (25) 345 (50) 100 (14.5) 10 (1450) 9-44

TABLE 9.3 PROJ 24-11.doc Phase Sub- phase Start of Phase Description Requirements Possible Actions I None Prior to shipment to the project site Pre- certification of the molder Approved third-party certification: Molder will • Identify the organization providing this service. • Provide detailed information as to the procedure and tests used by this organization to verify the molder’s compliance with the specific requirements of this specification. • Provide written certification that all EPS blocks supplied to the project will meet the requirements specified in the project specifications. No approved third-party certification: • Contractor shall deliver a minimum of three full-size EPS blocks for each AASHTO EPS-block geofoam type to be used on the project to a location specified by the owner's agent. • Owner's agent will weigh, measure, sample and test a random number of blocks. Sampling and testing protocol will be the same as for Phase IIc MQA. • Molder should submit a letter stating that all EPS blocks supplied for the project are warranted to meet specification requirements and what MQC measures they employ. • Acceptance of the molder’s third- party certification by the owner’s agent will waive the need for pre- construction product submittal and testing. • No EPS blocks shall be shipped to the project until such time as all parts of Phase I MQA have been completed. 9-45

TABLE 9.3 PROJ 24-11.doc II IIa As the EPS blocks are delivered to the project site On-site visual inspection of each block delivered to the project site to check for damage as well as visually verify the labeled information on each block Approved third-party certification: • Each truckload. Owner’s agent should inventory each and every block. No approved third-party certification: • Each truckload. Owner’s agent should inventory each and every block. • Any blocks with significant physical damage or not meeting specifications will be rejected on the spot and placed in an area separate from those blocks that are accepted or marked “unacceptable” and returned to the supplier. 9-46

TABLE 9.3 PROJ 24-11.doc II IIb As the EPS blocks are delivered to the project site On-site verification that the minimum block dry density as well as the physical tolerances meet specificatio ns Approved third-party certification: • Each truckload. Initially, only one block per load. No approved third-party certification: • Each truckload. Each block for the first load then at least one block per load for subsequent truckloads. • If the selected block meets specifications with respect to its size and shape, and the mass agrees with that marked on the block, no further checking of the load for these parameters is required and the shipment is approved conditionally until the Phase IIc test results verify that the blocks meet specifications. • If the selected block does not meet specification, then other blocks in the truckload should be checked and none used until the additional checking has determined what blocks are unsatisfactory. • At the completion of this subphase, the construction contractor should be conditionally (until the Phase IIc test results verify that the blocks meet specifications) allowed to proceed with installing blocks. 9-47

TABLE 9.3 PROJ 24-11.doc II IIc As the EPS blocks are delivered to the project site Confirming the EPS engineering design parameters related to stiffness as well as the quality control strength parameters Approved third-party certification: • Discretion of owner’s CQA agent. For example, can be omitted entirely on a small project, can perform testing only at the beginning of a project, or can be done on an ongoing basis. No approved third-party certification: • Performed on all projects throughout the entire duration of the project • For each AASHTO EPS-block geofoam type at least one block will be selected for sampling from the first truckload. • Additional blocks may be selected at a rate of sampling not exceeding one sample for every 250 cubic metres (325 cubic yards) • Sampling to be performed per the locations indicated in Figure 9.4. • Lab. tests should be performed to check for compliance with the parameters shown in Table 9.2 to include the elastic-limit stress, initial tangent Young’s modulus, compressive strength, and flexural strength. • Portions of sampled blocks that are not damaged or otherwise compromised by the sampling can be used as desired by the contractor. • If unsatisfactory test results are obtained, the contractor may be directed to remove potentially defective EPS blocks and replace them with blocks of acceptable quality at no additional expense to the owner. 9-48

TABLE 9.3 PROJ 24-11.doc II IId As the EPS blocks are placed As-built drawing(s) • Owner’s agent with the cooperation of the contractor will prepare as-built drawing(s) as well as perform additional record keeping to document the location of all EPS blocks placed for the project. Note: A truckload of EPS blocks is intended to mean either a full length box- or flat-bed trailer of typical dimensions, i.e., approximately 12 m (40 ft) or more in length, fully loaded with EPS blocks. The volume of EPS in such a truckload would typically be on the order of 50 to 100 m3 (65 to 130 yd3). 9-49