有机水硬性半柔基层性能及微观特征研究

Study on the Properties and Microscopic Characteristics of OrganicWater-hard Semi-flexible Base Layers

为研究掺乳化沥青半刚性基层混合料性能及微观特征,在了解原材料物化特性和确定水泥掺量的基础上,设计5种混合料配合比,通过无侧限抗压强度试验、干缩和温缩试验研究了混合料不同期龄的力学与抗裂性能,并根据EDS能谱和SEM扫描电镜分析物质成分和微观结构对性能的影响。结果表明:随乳化沥青有效掺量的增加,混合料无侧限抗压强度和干缩系数、温缩系数呈下降趋势;当掺量小于2%时,7 d无侧限抗压强度满足极重交通荷载一级公路强度要求。微观特征分析发现沥青与水泥水化产物共同构成空间结构网络,使得混合料结构更加密实,但沥青阻碍了部分水泥水化,也会影响空间结构网络的形成,最终使混合料的无侧限抗压强度降低,抗裂性能增强。

In order to study the performance and microscopic characteristics of semi-rigid base mix with emulsified asphalt,on the basis of understanding the physical and chemical properties of raw materials and determining the amount of cement dosing,we designed five kinds of mix ratios,and investigated the mechanical and cracking performance of the mix at different ages through the unconfined compressive strength test,drying shrinkage and temperature shrinkage test,and analysed the effects of the material composition and microstructure of the performance according to the EDS spectroscopy and SEM scanning electron microscopy.The results showed that with the increase of the effective dosage of emulsified asphalt,the unconfined compressive strength and the coefficient of drying shrinkage and temperature shrinkage of the mixture showed a decreasing trend;when the dosage was less than 2%,the 7 d unconfined compressive strength met the strength requirements of the first class highway with extremely heavy traffic load.Microscopic character analysis found that asphalt and cement hydration products together constitute a spatial structure network,making the mix structure more dense,but asphalt impedes part of the cement hydration,but also affects the formation of the spatial structure network,and ultimately make the mix of the lower unconfined compressive strength,cracking resistance enhanced.