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From page 13... ... 13 Concrete Properties For each air-entraining admixture, the dosages required to achieve an air content of 61 percent varied significantly for each variable. The mixes with crushed stone and low w/c ratio required the highest dosages, sometimes five times that used for high w/c ratio. Read the entire page →
From page 14... ... 14 0 1000 2000 3000 4000 5000 6000 7000 1 98765432 10 11 12 13 14 15 16 Mix No. Co m pr es si ve S tre ng th , p si B C D E M S Admixture Type Figure 1. Read the entire page →
From page 15... ... Factors Affecting Spacing Factor An analysis of variance (ANOVA) was conducted for the hardened air content spacing factor. Read the entire page →
From page 16... ... 16 Mixture Designation Ambient Temp, oF Concrete Temp, oF Slump, in. Air, % Unit Weight, lb/ft3 Total Air, % Specific Surface, (in2/in.3) Read the entire page →
From page 17... ... 17 Mixture Designation Ambient Temp, oF Concrete Temp, oF Slump, in. Air, % Unit Weight, lb/ft3 Total Air, % Specific Surface, (in2/in.3) Read the entire page →
From page 18... ... individual or combined data set analyses. Significant twoway interaction effects include duration-temperature (DURxTEMP) Read the entire page →
From page 19... ... crushed (negative coefficient for independent variable SHAPED) , and increases with cement alkali level (positive coefficient for independent variable ALKD) Read the entire page →
From page 20... ... and relatively lower for Admixture M As the concrete temperature increased from 73 F to 90 F, the average compressive strength decreased by approximately 9 percent. Read the entire page →
From page 21... ... Independent Signif. Signif. Read the entire page →
From page 22... ... Independent Signif . S ignif . Read the entire page →
From page 23... ... Independent Signif. Signif. Read the entire page →
From page 24... ... Independent Signif. Signif. Read the entire page →
From page 25... ... 25 decreased. The significant variables common to the flexural strength analysis at low and high temperatures were the coarse aggregate shape and the two-way interaction of duration and coarse aggregate shape. Read the entire page →
From page 26... ... -1500 -1000 -500 0 500 1000 1500 1 98765432 10 11 12 13 14 15 16 Mix Number Admixture Type Co m pr es si ve S tre ng th D iff er en ce , p si [av era ge co mp res siv e s tre ng th mi nu s a ve rag e co m pr es siv e st re ng th u sin g Ad m ix. Read the entire page →
From page 27... ... 27 coarse aggregate shape, and concrete temperature and watercement ratio. Factors affecting the average flexural strength change include the dummy variable for the different admixtures, mixing time duration, concrete temperature, water-cement ratio, cement alkali level, and the two-way interactions of mixing duration and coarse aggregate shape, mixing duration and water-cement ratio, concrete temperature and water-cement ratio, concrete temperature and cement alkali level, coarse aggregate shape and water cement ratio, coarse aggregate shape and cement alkali level, and water cement ratio and cement alkali level. Read the entire page →

From page 13...

... 13 Concrete Properties For each air-entraining admixture, the dosages required to achieve an air content of 61 percent varied significantly for each variable. The mixes with crushed stone and low w/c ratio required the highest dosages, sometimes five times that used for high w/c ratio.