防裂材料对整形机制砂混凝土抗裂性能的影响及工程实证  

Influence of cracking prevention materials on crack resistance of shaped manufactured sand concrete and engineering demonstration

作　　者：费壮 顾瑞[1] 万瑞 刘凯 张高展 FEI Zhuang;GU Ruil;WAN Rui;LIU Kai;ZHANG Gaozhan(Jiangsu China Construction Ready Mixed Concrete Co.,Ltd.,Nanjing 210033,China;School of Materials and Chemical Engeering,Anhui Jianzhu University,Hefei 230009,China)

机构地区：[1]江苏中建商品混凝土有限公司,江苏南京210033 [2]安徽建筑大学材料与化学工程学院,安徽合肥230009

出　　处：《混凝土》2025年第2期155-161,共7页Concrete

基　　金：国家自然科学基金(U21A20149)。

摘　　要：为配制出抗裂性能优异的搅拌站整形机制砂混凝土,利用单面轮廓投影法对整形机制砂的粒形特征进行对比分析,通过抗压强度试验、平板开裂试验、抗水渗透和抗氯离子渗透试验,研究了掺聚丙烯纤维、膨胀剂、复合纤维膨胀剂对整形机制砂和河砂混凝土性能的影响,并结合扫描电子显微镜从微观结构上分析掺防裂材料对机制砂混凝土的作用机理。结果表明:整形机制砂颗粒圆润度低于河砂,但明显优于市售机制砂;掺合料复掺并增大比例和改用复合纤维膨胀剂对机制砂混凝土具有减水、改善经时损失和提高抗压强度效果,机制砂混凝土单位面积的总开裂面积可达到低于60 mm^(2)/m^(2),抗裂等级为V级;复合纤维膨胀剂的超叠加效应下,纤维使膨胀剂加强了填充的作用,膨胀剂优化了纤维-基材界面之间的界面黏结强度,有效改善了混凝土微结构。最后工程实证表明:用于地下大体积工程中的整形机制砂混凝土具有优异的防裂抗渗效果。In order to make shaped manufactured sand concrete with excellent crack resistance performance in the mixing plant,a single sided contour projection method was used to compare and analyze the particle shape characteristics of shaped manufactured sand.Through compressive strength tests,plate cracking tests,water permeability and chloride ion permeability tests,the effects of adding polypropylene fibers,expansion agents,and composite fiber expansion agents on the properties of shaped manufactured sand and river sand concrete were studied,Combined with scanning electron microscope,the effect mechanism of anti crack material on machine-made sand concrete is analyzed from the microstructure.The results show that the roundness of self-made machine made sand particles is lower than that of river sand,but significantly better than that of commercially available machine made sand;The addition of admixtures and increasing the proportion,as well as the use of composite fiber expansion agents,have the effect of reducing water content,improving time loss,and increasing compressive strength at 7d and 28d for machine made sand concrete.The total cracking area per unit area of machine made sand concrete can reach less than 60mm^(2)/m^(2),and the crack resistance level is Grade V.Under the superimposition effect of composite fiber expansion agent,the fiber enhances the filling effect of the expansion agent,and the expansion agent optimizes the interfacial bonding strength between the fiber substrate interface,effectively improving the microstructure of concrete.Finally,engineering demonstration shows that the shaped manufactured sand concrete used in underground large-scale engineering has excellent anti crack and anti permeability effects.

关 键 词：整形机制砂混凝土 粒形特征 抗裂性能 微观结构 工程实证 

分 类 号：TU528.01[建筑科学—建筑技术科学]