摘要
近年来,我国环境保护力度较大,河砂资源无法满足建筑工程的需求,机制砂已逐步成为建筑工业的主要细骨料。但大量实践证明,机制砂相较于河砂存在石粉含量高、颗粒级配差、骨料粒形差等缺点,再加上受制于母岩岩性、制砂方式等因素,对混凝土的工作性能、力学性能以及耐久性能均产生了不可忽视的影响。因此,综合讨论了国内外有关机制砂混凝土性能的研究进展,研究表明:为保证混凝土的力学性能(抗压强度和弹性模量),应控制机制砂的石粉含量,各国对于机制砂石粉含量的标准要求石粉含量应当控制在1%~20%内;合理的机制砂颗粒级配可以降低混凝土的空隙率,从而提高其力学性能;骨料粒形对机制砂混凝土的性能影响显著,针片状颗粒含量越高,混凝土的流动度和强度越低;此外制砂方式不同,对混凝土性能的影响也不同,选择湿法制砂时,合适的絮凝剂以及适宜的掺量能最大程度地降低其对混凝土性能的负面影响;钙质机制砂在分散性和石粉低吸附性上优于硅质机制砂。针对上述问题,提出了相应问题的解决对策,为进一步改善机制砂混凝土的性能,推动机制砂混凝土产业发展提供参考和思路。
In recent years,the environmental protection efforts are greater in our country,river sand resources can not meet the demand of construction projects,machine-made sand has gradually become the main fine aggregate for the construction industry.However,it is widely proved that the machine-made sand has the disadvantages of high stone powder content,poor particle grading and poor aggregate particle shape compared with river sand,plus the constraints of parent rock lithology,sand making method and other factors,these have a non-negligible impact on the workability,mechanical properties and durability performance of concrete.This paper discusses the progress of domestic and foreign research on the performance of machine-made sand concrete,shows that in order to ensure the mechanical properties of concrete(compressive strength and modulus of elasticity),the stone powder content of machine-made sand should be controlled,the national standards for the stone powder content of machine-made sand should be controlled within 1%to 20%;reasonable particle grading of machine-made sand can reduce the void ratio of concrete,thereby improving its mechanical properties;the higher the content of lamellar particles,the lower the flow and strength of concrete;in addition,different sand production methods have different effects on the performance of concrete;when choosing wet sand production,the appropriate flocculant and the appropriate amount of admixture can minimize its negative impact on the performance of concrete;calcareous machine-made sand is better than siliceous machine-made sand in terms of dispersibility and low adsorption of stone powder.In response to the above issues,proposing solutions to corresponding problems,providing reference ideas for further improving the performance of machine-made sand concrete and promoting the development of the machine-made sand concrete industry.
出处
《混凝土世界》
2023年第6期71-76,共6页
China Concrete
基金
防灾科技学院研究生创新基金项目(ZY20230317)。
关键词
机制砂
石粉含量
颗粒级配
骨料粒形
Machine-made sand
stone powder content
particle grading
aggregate particle shape
