温度对新拌水泥沥青浆体流动性和水化速率的影响

INFLUENCE OF TEMPERATURE ON FLOWABILITY AND HYDRATION RATE OF FRESH CEMENT ASPHALT BINDER

研究了温度对不同沥青含量的新拌水泥沥青浆的流动性和水化速率的影响,以揭示该类复合胶凝材料流动性和水化速率的温度敏感性规律。在0,20℃和40℃下测量浆体的扩展度,获得了流动性随温度变化的基本规律。通过测定新拌浆体凝结硬化过程中半绝热温升来研究温度对水泥水化过程的影响。结果表明:随温度的降低,水泥水化速率下降,浆体初始流动性和流动保持性增强;随沥青掺量的增大,初始流动性和水化速率的温度敏感性降低,流动保持性的温度敏感性增大;含阳离子乳化沥青的浆体初始流动性、流动保持性以及水泥水化延缓程度受温度的影响均大于含阴离子乳化沥青的浆体。水泥水化、乳化沥青在水泥颗粒表面的吸附以及沥青的破乳是决定新拌水泥沥青浆流动性的关键因素。

The effects of temperature on flowability and hydration rate of the fresh cement asphalt binder with different asphalt emulsion content were investigated.The spread diameters of fresh cement asphalt paste were measured at 0,20 and 40℃during different shelf time respectively.Semi-adiabatic temperatures of cement asphalt binder during setting were monitored in order to understand the hydration behavior of cement under different temperatures.The results show that hydration rate of cement decreases obviously with the decrease of temperature.Lower temperature leads to higher initial flowability and longer flow-retention time during shelf time of fresh cement asphalt binder.The temperature sensitivity of initial flowability and the hydration rate decrease with the increase in asphalt content,whereas that of flowability-retention increases.For the fresh cement asphalt binder with cationic asphalt emulsion, the temperature sensitivities of initial flowability,flowability-retention and hydration-retardation are more pronounced than those with anionic asphalt emulsion.It was believed that the cement hydration,adsorption of asphalt particles on cement grains,and agglomeration of asphalt emulsion play essential roles on determining the flowability behavior of cement asphalt binder.