人工砂中的石粉对混凝土性能的影响与作用机制  

Influence and Mechanism of Stone Powder in Artificial Sand on Concrete Performance

作　　者：郭子晗[1] 范晓亮 GUO Zihan;FAN Xiaoliang(Sinohydro Bureau 7 Co.,LTD.,Chengdu Sichuan 610213)

机构地区：[1]中国水利水电第七工程局有限公司,四川成都610213

出　　处：《四川水力发电》2023年第6期82-85,共4页Sichuan Hydropower

摘　　要：石粉是人工砂区别于天然砂的主要特征之一,石粉的存在会对混凝土的工作性能、物理力学性能和耐久性造成巨大的影响。笔者阐述了通过抗压和劈裂等室内力学试验,针对水电工程中常见的石灰岩与花岗岩研究了不同含量的人工砂石粉对混凝土性能产生的影响。研究中采用的试验,扩大了相关规范中规定的6%~18%的人工砂石粉含量范围为5%~30%,并结合X射线衍以及扫描电镜对混凝土的微观结构与化学成分进行了分析,揭示出石粉与混凝土的耦合作用机制。试验结果表明:基于所用混凝土配合比,随着石粉含量的增大,混凝土的抗压与抗拉强度出现了先增大、后减小的趋势,其最优石粉含量为20%。当石粉含量从5%开始增加时,晶核作用及填充作用均强于因石粉含量增加导致的水化反应不充分的负面作用,进而使混凝土的微小孔隙被水化产物所填充,从而提升了混凝土的力学性能。但随着石粉含量的继续增加,当这种晶核作用及填充作用的影响不能够抵消混凝土水化不完全的负面影响时,混凝土的强度开始降低。Stone powder is one of the main features that distinguishes artificial sand from natural sand,and its presence can have a huge impact on the workability,physical and mechanical properties and durability of concrete.This paper describes the impact of different contents of artificial sand and stone powder on concrete properties through indoor mechanical tests such as compression and splitting,focusing on common limestone and granite in hydropower projects.The tests extended the stone powder content range of 6%~18%specified in the specification to 5%~30%,and combined with X-ray diffraction and scanning electron microscopy to analyze the microstructure and chemical composition of concrete,revealing the coupling mechanism between stone powder and concrete.The test results show that,based on the used concrete ratio,as the stone powder content increases,the compressive and tensile strength of concrete tend to increase and then decrease,and the optimal stone powder content is 20%.When the stone powder content increases from 5%,the nucleation and filling effects are stronger than the negative effect of insufficient hydration reaction due to the increase of stone powder content,which leds to the filling of micro pores of concrete by hydration products,thus improving the mechanical properties of concrete.However,as the stone powder content continues to increase,the strength of the concrete starts to decrease when this nucleation and filling effect does not counteract the negative effect of incomplete hydration of the concrete.

关 键 词：人工砂混凝土 石粉含量 力学性能 微观结构 耦合作用机制 

分 类 号：TV7[水利工程—水利水电工程] TV43TV42