水泥粉煤灰稳定炉渣-煤矸石混合料的收缩试验

Shrinkage Test of Cement and Fly Ash Stabilized Slag-coal Gangue Mixture

利用炉渣、粉煤灰和煤矸石配制路面基层混合料可以有效利用工业固废,基层混合料收缩性能的优劣直接决定了其路用性能。选用0~4.75 mm粒径炉渣按照不同比例(0、25%、50%、75%、100%)替代同粒径的煤矸石,采用掺入3%、4%、5%和6%的水泥,设计了8组水泥粉煤灰稳定炉渣-煤矸石混合料试验,通过温缩和干缩试验,分析了炉渣替代率和水泥掺量的变化对混合料收缩性能的影响规律。结果表明:温缩应变随炉渣替代率的增大而增大,随水泥掺量的增大而减小,-10~-20℃时温缩系数较大;干缩应变随炉渣替代率的增大而减小,随水泥掺量的增大而增大;干缩应变在7 d龄期内增长速率较快,30 d龄期内的干燥收缩率占整个龄期的86.5%,30 d龄期后干缩应变逐渐趋于稳定;当水泥掺量为5%,炉渣替代率为50%~75%时,混合料的干缩系数和温缩系数均较小。

Using slag,fly ash and coal gangue to prepare pavement base mixture can effectively utilize industrial solid waste.The shrinkage performance of pavement base mixture directly determines its pavement performance.The slag with 0~4.75 mm particle size was selected to replace the gangue with the same particle size in different proportions(0,25%,50%,75%,100%),and the cement was mixed with 3%,4%,5%and 6%,eight groups of cement and fly ash stabilized slag-coal gangue mixture tests were designed.The effect of slag substitution rate and cement content on shrinkage performance of mixture was analyzed.The results show that the temperature shrinkage strain increases with the increase of slag substitution ratio and decreases with the increase of cement content,and the temperature shrinkage coefficient is larger at-10~-20℃.The dry-shrinkage strain decreases with the increase of slag substitution rate and increases with the increase of cement content.The dry-shrinkage strain increases rapidly in the 7 d age,and the dry-shrinkage rate in the 30 d age accounts for 86.5%of the whole age,after which the dry-shrinkage tends to be stable gradually.When cement content is 5%and slag substitution rate is 50%~75%,dry shrinkage coefficient and temperature shrinkage coefficient of mixture are small.