机制砂混凝土工作性能及强度影响因素研究

Study on different factors for working performance and strength of concrete with machined-sand

研究了颗粒岩性及形貌对机制砂混凝土工作性能和抗压强度的影响规律。结果表明,不同颗粒岩性对机制砂混凝土工作性能影响与原岩的表观结构、石粉含量、MB值等因素相关,石灰岩和石英岩为原岩的机制砂混凝土工作性能明显优于花岗岩和片麻岩为原岩的机制砂混凝土。不同岩性种类对机制砂混凝土抗压强度影响因素主要包括原岩的表观结构、原岩的压碎指标,以石灰岩为原岩的机制砂混凝土抗压强度最优。采用冲击式破碎和反击式破碎的机制砂颗粒形貌最接近球形,机制砂比表面积相对较小,拌合物的工作性能良好。经辊式破碎的机制砂颗粒粗糙度较大,这提高了骨料与浆体间的机械咬合作用,提高了混凝土的抗压强度。

The effects of particle lithology and morphology on the working performance and compressive strength of concrete with manufactured sand were studied through experiments.The test results show that the influence of different grain lithology on the working performance of concrete is related to the apparent structure,limestone content and MB value of raw rock.The working performance of manufactured sand concrete with limestone and quartzite as raw rock is obviously better than that of manufactured sand concrete with granite and gneiss as raw rock.The influence factors of different lithological types on the compressive strength of manufactured sand concrete mainly include the apparent structure of the original rock and crushing index of the original rock.The compressive strength of manufactured sand concrete with limestone as the original rock is the best.The particle morphology of the machine-made sand with impact crushing and impact crushing is the closest to spherical shape,the specific surface area of the machine-made sand is relatively small,the slurry thickness of the aggregate wrapped in the mixture increases correspondingly,and the performance of the mixture is good.The roughness of the crushed sand particles is relatively high,which improves the mechanical biting between aggregate and paste,and enhances the compressive strength of concrete.