摘要
为探究水泥稳定级配碎石在低水泥剂量下的干缩特性,采用1%、2%和3%三种不同剂量的水泥,分别加入到三种不同级配(分为设计型、连续型、悬浮型)的集料中制备出水泥稳定碎石,研究其在不同水泥剂量、失水率、龄期条件下水泥稳定级配碎石干缩应变规律。研究结果表明,掺有3%水泥的悬浮型水泥稳定级配碎石具有最大的干缩应变值和平均干缩系数,均约为掺有1%水泥的水泥稳定级配碎石相应指标的4倍。在干缩前期,试件中的水分蒸发较快,第1d失水率达到总失水率的25%以上,前3d的失水率可达到总失水率的60%,15d后,设计级配及连续级配的失水率基本不变,悬浮级配混合料25d后失水率趋于稳定。当失水率小于3%时,试件的干缩应变都处在较小范围,占总干缩应变的30%以下。因此在基层施工结束后,失水率应控制在3%以内,以减少基层的早期干缩裂缝。
To investigate the dry shrinkage characteristics of cement stabilized graded crushed stone(CSGCS)at low cement dosages,three different dosages of cement,1%,2%,and 3%,were added into each of the three different gradations(designated as designed type,continuous type and suspension type)respectively to prepare CSGCS.The dry shrinkage strains of the CSGCS were studied under different cement dosages,water loss rates and ages.The results show that suspension type CSGCS with 3%cement has the largest dry shrinkage strain value and average dry shrinkage coefficient,both of which are approximately 4 times of the corresponding index of CSGCS mixed with 1%cement.In the early stage of shrinkage,the water in the sample evaporates quickly,and water loss rate on the first day reaches more than 25%of the total water loss rate.The rate of water loss in the first three days can reach 60%of the total water loss rate,and after the age reaches 15 days,the water loss rate of the design gradation and continuous gradation remained basically unchanged,and the water loss rate tended to stabilize after the suspended gradation CSGCS reached the age of 25 days.When the water loss rate is less than 3%,the dry shrinkage strain of the specimens is in a smaller range,accounting for less than 30%of the total shrinkage strain.Therefore,after the completion of base course construction,the rate of water loss should be controlled within 3%in order to reduce early shrinkage crack of base course.
出处
《福建建设科技》
2018年第6期39-42,51,共5页
Fujian Construction Science & Technology
基金
福建省交通运输科技项目
编号:201509
关键词
低剂量
水泥稳定级配碎石
干燥收缩
失水率
龄期
Low dosage
Cement stabilized gravel
Drying shrinkage
Water loss rate
Age
