水泥稳定凝灰岩机制砂级配碎石路用性能

Mixture of Graded Crushed Stone and Tuff Sands by Mechanical Extraction and its Application in Road Base Engineering

为推广凝灰岩在道路工程中的应用,采用凝灰岩机制砂替代细集料,设计混合料级配,通过击实实验确定水泥稳定碎石最佳含水量和最大干密度,并制备试件,测试混合料无侧限抗压强度、劈裂强度、水稳性及抗冻性等路用性能。结果表明:3%和5%水泥用量的水泥稳定凝灰岩机制砂级配碎石可分别满足底基层和基层的强度要求;在较短龄期内,水泥稳定凝灰岩机制砂级配碎石无侧限抗压强度比水泥稳定天然集料的略高,劈裂强度相差不大,水稳系数接近;水泥用量对无侧限抗压强度影响显著。由此说明水泥稳定凝灰岩机制砂级配碎石总体性能满足道路基层使用要求。

In order to promote the application of tuff mines in road engineering,the performance of cement-stabilized mixture of tuff sands by mechanical extraction and graded macadam was investigated. The unconfined compressive strength( UCS),cleavage strength,water stability and frost resistance of the mixture were tested and compared with those of fine aggregates. The optimum water content and maximum dry density of cement-stabilized macadam with tuff sands were determined by compaction experiments. Results showed that the 3% and 5 % cement stabilized tuff sands mixed with graded macadam could meet the strength requirements of the sub-base and the base course,respectively. The UCS of tuff sands mixture was slightly higher than that of the cement-stabilized natural aggregate in a short period. The cleavage strength had insignificant difference between those of tuff sands mixture and fine aggregates mixture,while the cement usage had significant effects on it. The coefficient of water stability of cement-stabilized tuff sands mixture was very close to that of the cement-stabilized natural aggregates. Therefore,the tuff sands mixture was feasible for application in road base engineering basically.