细集料类型对混凝土力学性能及孔隙结构影响  

Influence of fine aggregate type on mechanical properties and pore structure of concrete

作　　者：高猛 姚占全[1] 王海龙[1] GAO Meng;YAO Zhanquan;WANG Hailong(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot,Inner Mongolia 010018,China)

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,内蒙古呼和浩特010018

出　　处：《排灌机械工程学报》2024年第12期1266-1271,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(52069024)。

摘　　要：利用机制砂、风积沙和河砂制备不同水胶比的混凝土进行抗压、轴心抗压、劈裂抗拉、抗折和黏结强度测试以及坍落度测试,结合微观孔隙结构变化明确不同细骨料对混凝土性能的影响机理.试验结果表明:机制砂增强了混凝土的抗压强度、黏结强度、受拉变形能力和韧性,而风积沙则降低了混凝土力学性能;随着水胶比和减水剂含量的增加,不同细骨料混凝土的力学性能有着不同程度的降低,与普通河砂混凝土相比,风积沙和机制砂混凝土的力学性能下降程度较小;机制砂和风积沙降低了集料之间的干涉作用、提升了细骨料填充率和开口孔隙占比使混凝土内部更加致密强化孔隙结构,但二者均使混凝土内部的大孔隙占比增多;机制砂和风积沙均大幅度降低混凝土的工作性能,随着水胶比和减水剂含量的增加,坍落度大幅增加,但当水胶比和减水剂含量过大时导致风积沙混凝土凝结硬化时间延长3倍左右,且内部处于湿润和黏结性较弱的状态.Concrete with different water-cement ratios was prepared using machine-made sand,aeolian sand,and river sand,and the compressive,axial compressive,splitting tensile,flexural,bond strength and slump tests were carried out.The influence of different fine aggregates on concrete performance was clarified by examining changes in the microscopic pore structure.The test results show that the manufactured sand enhances the compressive strength,bond strength,tensile deformation capacity,and toughness of concrete,while the aeolian sand reduces the mechanical properties of concrete.With the increase of water-binder ratio and water-reducing agent content,the mechanical properties of concrete with different fine aggregates decrease to varying degrees.Compared with ordinary river sand concrete,the mechanical properties of aeolian sand and machine-made sand concrete decrease to a lesser extent.Machine-made sand and aeolian sand reduce the interference between aggregates,increase the fine aggregate filling rate and the proportion of open pores,making the concrete more dense and strengthening the pore structure,but both of them increase the proportion of macropores in the concrete.Both machine-made sand and aeolian sand significantly reduce the working performance of concrete.With the increase of water-cement ratio and water reducing agent content,the slump increases significantly.However,when the water-cement ratio and water-reducing agent content are too large,the setting and hardening time of aeolian sand concrete is prolonged by about 3 times,and the interior is in a moist and weakly adhesive state.

关 键 词：细集料 混凝土 力学性能 工作性能 填充率 孔隙结构 

分 类 号：TU528[建筑科学—建筑技术科学]