机制砂对高强混凝土体积稳定性的影响  

Effects of Manufactured-fine Aggregates on Volume Stability of High-strength Concrete

作　　者：王稷良[1] 周明凯[1] 朱立德[1] 贺图生[1] 

机构地区：[1]武汉理工大学硅酸盐材料工程教育部重点实验室,武汉430070

出　　处：《武汉理工大学学报》2007年第10期20-24,共5页Journal of Wuhan University of Technology

基　　金：西部交通建设科技项目(200331881106)

摘　　要：采用对比的方法,研究了天然砂、机制砂及机制砂中的石粉质量分数对高强混凝土的工作性、抗压强度、弹性模量、干缩和受压徐变的影响。结果表明:机制砂中适量(7%—10.5%)的石粉并不会劣化混凝土的工作性能,甚至可以改善混凝土的工作性能,且随石粉质量分数的提高,机制砂混凝土的抗压强度逐渐增大;石粉质量分数较低(小于7%时)的机制砂混凝土弹性模量接近于天然砂混凝土的弹性模量,但当石粉质量分数较高时,机制砂混凝土的弹性模量降低;石粉质量分数对机制砂高强混凝土干缩的影响与干缩龄期密切相关,石粉质量分数较高的机制砂混凝土的前7 d龄期干缩值比河砂混凝土大,而后龄期干缩值相差不大,同时,掺入粉煤灰使机制砂混凝土各龄期的干缩值减小;石粉质量分数为7%的机制砂混凝土徐变度、徐变系数与天然砂混凝土较为接近。In this paper, the influence of natural sands, manufactured-fine aggregates and micro-fines in the manufacturedfine aggregates on some performances of high-strength concrete was tested by the method of contrast, which included workability, compressive strength, Young＇ s modulus, drying shrinkage and creep. The results showed that the reasonable content （7 %-10.5 % ） of micro-fines couldn＇t deteriorate the workability of concrete, but may even improve it. And the compressive strength increased gradually with micro-fines content. The manufactured-fine aggregated concrete with low micro-fines content （smaller than 7% ） had the Young＇s modulus which approached that of the natural sands concrete, but the Young＇s modulus would reduce when the content was high; The influence of the micro-fines content on drying shrinkage performance of the manufactured-fine aggregates high-strength concrete was closely related with age. The shrinkage rate of the manufactured-fine aggregates concrete in the former 7 d age was bigger than that of the natural sand concrete, but the difference of the shrinkage rate in the late age was not marked. Meanwhile the shrinkage rate would reduce with the fly ash mixing into it. The creep degree and creep coefficient of the manufactured-fine aggregates with 7 % micro-fines content were close to the natural sand concrete.

关 键 词：机制砂 天然砂 高强混凝土 体积稳定性 

分 类 号：TU528[建筑科学—建筑技术科学]