某添加剂在水泥土搅拌法中的应用

为了改善水泥土的力学性能,对某添加剂进行了研究.做了水泥掺入比(水泥掺入质量/加固土质量)aw=12%;水灰质量比C=0.5;添加剂掺入比(添加剂掺入质量/水泥掺入质量)ap分别为0,2%,4%,5%,6%,8%,10%,12%,14%,16%,20%,24%,26%,28%,30%,32%的16组试样.作为对比,还做了aw=15%,C=0.5的1组试样.室内7,30和90d龄期的无侧限抗压强度试验结果表明,该添加剂对水泥土的强度有增强作用,但其早强作用尤为显著.其加固水泥土的机理主要与三硫型水化硫铝酸钙的生成有关.对某工程的水泥土搅拌桩制定了合理的添加剂配方(aw=14%,ap=15%).实践表明,该添加剂有效地提高了水泥土的早期强度和标准强度,可保证成桩质量,缩短施工工期,降低工程成本,减小建筑物沉降.

Application of an additive in cement deep mixing method

The mechanical property of cement-stabilized soil(CSS) can be improved with an additive.16 groups of CSS samples(the percentage of cement content aw was 12% by weight of soil,water cement ratio C was 0.5) were prepared with 16 different percentages of additive content ap(i.e.0,2%,4%,5%,6%,8%,10%,12%,14%,16%,20%,24%,26%,28%,30% and 32% by weight of cement).A group of CSS samples was also prepared with aw=15%,C=0.5 for comparison.Laboratory unconfined compressive strength tests were carried out after 7-,30-and 90-day curing periods.The test results indicate that the additive leads to the strength improvement of CSS,and the improvement of early stage strength is more significant.The mechanism in reinforcing CSS is concerned with the formation of ettringite.The legitimate additive recipe (aw=14% and ap=15%) for the cement deep mixing pile in a project was drew up.Engineering practice indicates that the additive improves effectively the early stage and standard strength of CSS, which can assure the pile quality,shorten the construction period,lower the engineering cost and reduce the building settlement.