养护温度与沙漠砂替代率对机制砂混凝土抗压强度与孔结构的影响  

Effects of curing temperature and desert sand replacement rate on compressive strength and pore structure of manufactured sand concrete

作　　者：郭雨雨 周海龙[1] 张洁 韩长君 王海龙[1] GUO Yuyu;ZHOU Hailong;ZHANG Jie;HAN Changjun;WANG Hailong(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot,Inner Mongolia 010018,China;School of Materials Science and Engineering,Shenyang Jianzhu University,Shenyang,Liaoning 110168,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 [2]沈阳建筑大学材料科学与工程学院,辽宁沈阳110168

出　　处：《排灌机械工程学报》2025年第1期45-52,共8页Journal of Drainage and Irrigation Machinery Engineering

基　　金：内蒙古自然科学基金资助项目(2024LHMS05026);国家自然科学基金资助项目(52069024);内蒙古自治区重大科技专项(2021ZD0007);内蒙古自治区研究生教育教学改革项目(JGCG2023065)。

摘　　要：为探究不同养护温度下沙漠砂替代率对机制砂混凝土抗压强度及孔结构的影响规律,试验选用不同比例的沙漠砂替代机制砂用作细骨料配制C40混凝土.测试不同沙漠砂替代率下混凝土的抗压强度,借助SEM,XRD、核磁共振等测试手段分析不同养护温度下,混凝土水化产物、微观形貌及孔结构.结果表明:标准养护下沙漠砂体积替代率为30%时,混凝土抗压强度最高;沙漠砂替代机制砂降低了混凝土低温养护下7 d强度损失率,减缓了高温水泥水化的速率;30%的沙漠砂替代机制砂,改善了骨料的颗粒级配,优化了混凝土内部的孔隙结构,从而提高了体系的密实性;考虑到混凝土孔隙结构的复杂性,引入分形维数间接评价混凝土的孔隙特征,其分形维数具有分段性;将分形维数与孔径分布进行线性拟合,分形维数与无害孔呈正比关系,与多害孔呈反比关系.该研究可为10~30℃养护下混合砂混凝土的研究与实践提供一定的参考.In order to investigate the effect of desert sand replacement rate on the compressive strength and pore structure of manufactured sand concrete at different curing temperatures,different proportions of desert sand were utilized to replace manufactured sand as fine aggregate to prepare C40 concrete.The compressive strength of concrete under different desert sand replacement rate was tested.The hydration products,micro-morphology and pore structure were analyzed by SEM,XRD and nuclear magnetic resonance methods.The results show that the compressive strength of concrete is the highest when the volume replacement rate of desert sand is 30%under standard curing.The replacement of manufactured sand by desert sand reduces the 7-day strength loss rate of concrete under low temperature curing,and slows down the hydration rate of high temperature cement.Replacing 30%of manufactured sand with desert sand,which improves the particle composition of the aggregates and optimizes the pore structure inside the concrete matrix,thus improving the overall compactness of the system.Given the intricate nature of concrete pore structure,the concept of fractal dimension is introduced as an indirect method to evaluate the pore characteristics.Notably,the fractal dimension exhibits segmentation.The fractal dimension is linearly fitted with the aperture distribution.The fractal dimension is positively proportional to harmless hole andinversely proportional to the multi-damage hole.This study can provide certain references for the research and practice of mixed sand concrete under curing temperatures ranging from 10℃ to 30℃.

关 键 词：养护温度 沙漠砂替代率 机制砂混凝土 抗压强度 孔结构 

分 类 号：TU528[建筑科学—建筑技术科学]