粉煤灰在三灰稳定砂中的抗裂性能分析

为了减小水泥灰土稳定砂基层材料收缩变形量,增强其抗裂能力,在水泥灰土稳定砂中掺加适量粉煤灰进行试验。通过调整水泥和石灰的比例研究了掺加粉煤灰的水泥灰土稳定砂(三灰稳定砂)各龄期的无侧限抗压强度、劈裂强度、抗压回弹模量和干缩系数等路用性能指标,使配比材料既能达到底基层的强度要求,又能显著改善其抗裂性能。通过电镜扫描和能谱分析,对其微观结构和粘结方式进行研究,得出了粉煤灰改善抗裂性能的微观机理。

Analysis on Cracking Resistance of Flyash in Cement-Lime-Flyash Stabilized Sand

In order to reduce shrinkage deformation of cement-lime stabilized sand base material and strengthen its cracking resistance,proper amount of flyash is added into cement-lime stabilized sand for test.Through adjustment of the proportion between cement and lime,pavement performance index such as unconfined compressive strength,fracture strength,compression resilient modulus and shrinkage coefficient of cement-lime stabilized sand added with flyash at different ages are studied so as to make the mixing material not only achieve strength requirement of subbase layer,but also improve its cracking resistance.Through electron microscope scanning and energy spectrum analysis method,the microstructure and bonding mode of cement-lime-flyash stabilized sand are studied.Finally,microcosmic mechanism of flyash improving cracking resistance is obtained.