石粉对机制砂混凝土早期收缩和开裂性能的影响研究  

Effect of Stone Powder on Early-Age Shrinkage and Cracking Behavior of Manufactured Sand Concrete

作　　者：陈迎 CHEN Ying(Port and Shipping Development Center of Guangxi Zhuang Autonomous Region,Nanning 530029,China)

机构地区：[1]广西壮族自治区港航发展中心,南宁530029

出　　处：《粉煤灰综合利用》2025年第2期44-48,90,共6页Fly Ash Comprehensive Utilization

摘　　要：为研究机制砂中石粉掺量对混凝土早期体积稳定性的影响,测试了不同石粉掺量的不同强度混凝土和易性、早期收缩和抗裂性能、抗压强度和孔隙结构。结果表明:掺加适量石粉可有效改善机制砂混凝土拌合物的保水性、黏聚性和抗离析性,有利于提高机制砂混凝土的抗裂性能和抗压强度;掺加过量石粉会增加混凝土的需水量和早龄期收缩率,降低其抗裂性能和硬化后的强度。对于C30机制砂混凝土,石粉掺量可放宽至20%;对于C50机制砂混凝土,石粉掺量应严格控制在10%以内。混凝土用机制砂中石粉掺量的最佳值应结合工程环境和实际用途确定,更有利于砂资源贫乏区域的机制砂混凝土扩大化应用。To study the influence of stone powder content on the early shrinkage and cracking performance of manufactured concrete,the working performance,early shrinkage,early cracking,compressive strength,and pore distribution of manufactured sand concrete with different strength and different contents were tested.The test results show that the addition of stone powder is beneficial to improve the water retention,cohesiveness,and anti-segregation performance of manufactured sand concrete but it will increase the amount of water reducing agent and early shrinkage strain of manufactured sand concrete.An appropriate amount of stone powder is beneficial to improve the crack resistance and compressive strength of manufactured sand concrete,but excessive stone powder will lead to the decrease of crack resistance and compressive strength.The stone powder content in manufactured sand can be relaxed to 20%for C30 concrete,and the content of stone powder should be controlled within 10%for the C50 concrete.The optimum value of stone powder content in manufactured sand for concrete should be determined in combination with engineering environment and practical use,which is more conducive to the expansion application of manufactured sand concrete in areas with poor sand resources.

关 键 词：机制砂混凝土 石粉掺量 体积稳定性 微观结构 

分 类 号：TU525[建筑科学—建筑技术科学]