Preparation of Warm Mix Asphalt Additive with Fly Ash

The structural characteristics of zeolite 4A make it to be the potential warm mix asphalt additive. Zeolite 4A containing crystal water can be synthesized with fly ash (FA) by fusion with sodium hydroxide prior to hydrothermal reaction. The influence of some factors on the water loss of synthesized zeolite 4A was investigated. The results indicate that the best technological conditions of synthesizing zeolite 4A containing crystal water with fly ash are as follows: the molar ratio of SiO2/A12O3 is 1.9; the molar ratio of Na2O/SiO2 is 2.0; the molar ratio of H2O/Na2O is 50; under the aging temperature of 65°C, the optimum aging time is 3 h; under the crystallization temperature of 90°C, the optimum crystallization time is 4 h.