砂岩对路面基层强度及水稳定性的影响研究

Research on Strength and Water Stability of Cement StabilizedSandstone Pavement Subgrade

为了分析砂岩对路面基层强度及水稳定性的影响,研究了不同砂岩置换率下,水泥稳定碎石混合料的无侧限抗压强度、劈裂强度及水稳定性随养护龄期的发展规律。此外,对试件的破坏形态、无侧限抗压强度和劈裂强度之间的关系进行了分析。结果表明:水泥稳定碎石混合料的无侧限抗压强度、劈裂强度和水稳定性均随砂岩置换率的增加而呈现下降趋势,当砂岩置换率为100%时,7、28、60、90 d的无侧限抗压强度较未掺砂岩试样分别降低了44.1%、21.8%、20.0%、23.4%;劈裂强度分别降低了38.8%、21.9%、29.6%、29.9%,而当砂岩置换率超过50%时,试样软化系数小于0.85,表明此时水泥稳定碎石混合料抵抗水损害能力较弱。抗压试件的破坏类型和传统的水泥稳定碎石破坏类型相同,为中心抗压破坏,劈裂试件的破坏主要是由界面过渡区和粗集料的破坏造成的。另外,水泥稳定碎石混合料的无侧限抗压强度与劈裂强度之间存在较强的线性相关关系。综合考虑砂岩对路面基层强度及水稳定性的影响,砂岩置换率不宜高于50%。

In order to analyse the effect of sandstone on the strength and water stability of pavement subgrade,the development of the unconfined compressive strength,splitting strength and water stability of cement-stabilised aggregates with different sandstone replacement rates were investigated with respect to the age of maintenance.In addition,the damage pattern of the specimens and the relationship between the unconfined compressive strength and the splitting strength were analysed.The results showed that the unconfined compressive strength,splitting strength and water stability of the cement-stabilised aggregates decreased with the increase of sandstone replacement rate,and when the sandstone replacement rate was 100%,the unconfined compressive strength decreased by 44.1%,21.8%,20.0%,23.4%at 7,28,60,90 d,respectively,compared with the unconfined sandstone specimens.38.8%,21.9%,29.6%,29.9%respectively,while the softening coefficient of the specimens was less than 0.85 when the sandstone replacement rate exceeded 50%,indicating that the cement-stabilised gravel mix was less resistant to water damage at this time.The damage type of the compressive specimens was the same as that of the conventional cement-stabilised aggregates,which was central compressive damage,and the damage of the split specimens was mainly caused by the damage of the interface transition zone and coarse aggregates.In addition,there is a strong linear correlation between the unconfined compressive strength of the cement-stabilised aggregates mix and the splitting strength.Considering the effect of sandstone on the strength and water stability of the pavement subgrade,the sandstone replacement rate should not be higher than 50%.