![]() ![]() The five combinations should span the recommended range of ratios for each activator. Use five different activator-to-fly ash combinations at the optimum matrix content. Then determine the optimum moisture content and maximum dry density for that blend.ĭetermine the most suitable proportions of activator to fly ash. Select an optimum matrix content at least two percent above the matrix content found at the maximum dry density. Plot the test results to identify a peak value or maximum dry density. Mold one test specimen at each fly ash content in accordance with ASTM C 593 compaction procedures at an estimated optimum moisture content.ĭetermine the molded dry density of each aggregate-fly ash blend. Add fly ash to the aggregate in five different proportions, starting at the lower limit (10 percent for coarse aggregate) and proceed in convenient increments to the upper limit (20 percent for coarse aggregate). Use proctor-size molds for all test samples. Screen the aggregate through a three-quarter-inch sieve, and use the portion passing the three-quarter-inch sieve for testing. Determine the particle size distribution of the aggregate. Obtain a representative sample of aggregate. The following steps summarize the procedures for a laboratory determination of mix proportions: ![]() The vacuum saturation test is normally used per ASTM C 593. It is important to ensure that adequate resistance to freeze-thaw cycling is achieved before the onset of colder months. Some states use different curing times and temperatures.ĭurability. Use standard proctor-sized specimens normal curing for lime/fly ash/aggregate mixtures is at plus 38 degrees C (100 degrees F) for 7 days. Closely controlled curing conditions are important as both time and temperature significantly affect strength.
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