水泥稳定废粘土砖再生集料基层材料性能试验

为研究掺入废砖块集料后水泥稳定碎石性能的变化规律,在试验中将废砖块集料按20%,40%,60%,80%和100%的比例（质量分数,后同）分别替代粗、细集料配制成2组集料后,用5%水泥拌和制备试件,并测试了混合料的击实特性和试件的抗压、抗折强度、抗压回弹模量、干缩以及抗冻性。结果表明：废砖块集料含量多的混合料最大干密度较小而最佳含水率较大;随着废砖块集料含量的增加,试件抗压强度、劈裂强度、抗压回弹模量、干缩应变和抗冻指数随之下降,而-15℃～40℃温缩应变随之增大;为满足规范对基层强度的最低要求,建议混合料中废砖块集料替代天然粗集料或细集料的替代率分别不要超过70%和90%;另外,在冬季严寒地区,还应该考虑废砖块集料的使用引起的强度损失。

Performance Test of Cement Stabilized Crushed Clay Brick for Road Base Material

In order to investigate the properties of cement stabilized aggregate which contains crushed clay brick(CCB),natural coarse aggregate and fine aggregate(20%,40%,60%,80% and 100% by weight) in the mixtures were replaced with CCB respectively and were blended with 5% cement to make specimens.Then the performance including compaction characteristic,unconfined compressive strength,splitting strength,resilience modulus,dry shrinkage strain,temperature shrinkage strain and frost resistance index was tested.The results show that the use of CCB increases the optimum moisture content and decreases the maximum dry density of the mixtures.Moreover,the incorporation of CCB reduces the unconfined compressive strength,splitting strength,resilience modulus,dry shrinkage strain and frost resistance index of the specimens in various degrees,but increases temperature shrinkage strains of-15 ℃-40 ℃.To meet the minimum strength requirements of cement stabilized aggregate in China,natural coarse aggregate and fine aggregate replacement level of CCB in the mixtures is suggested to be less than 70% and 90% respectively.Furthermore,it should be noted that,the cement stabilized aggregate which contains CCB should be used cautiously in the cold region due to its lower frost resistance performance.