Liu Dunwen, Zhang Wanmao, Tang Yu, Jian Yinghua, Lai Yongchao
School of Resources and Safety Engineering, Central South University, Changsha 410083, China.
Materials (Basel). 2022 May 13;15(10):3516. doi: 10.3390/ma15103516.
Machine-made sand instead of natural sand has become an inevitable choice for the sustainable development of the concrete industry. Orthogonal experiment and grey correlation analysis were used to investigate the performance of machine-made tuff sand concrete. The optimal concrete mix ratio of machine-made sand was obtained by orthogonal test and its working performance was verified. Grey correlation analysis was applied to compare the factors affecting the mechanical properties of the machine-made sand concrete. The test results show that the sand rate has the greatest degree of influence on slump and slump expansion. The mineral admixture has the greatest effect on the 7-day compressive strength of the concrete. Additionally, the water-cement ratio has the greatest influence on the 28-day compressive strength. The mechanical and working properties of the machine-made sand concrete reach the optimum condition when the mineral admixture is 20%, the sand rate is 46%, the stone powder content is 10% and the water-cement ratio is 0.30. Comparing different fine aggregate concretes of similar quality, we conclude that the mechanical and working properties of tuff sand concrete and limestone sand concrete and river sand concrete are similar. The compressive strengths of the mechanism concrete show the greatest correlation with roughness and the least correlation with stone powder content. The stone powder content has almost no effect on the compressive strength of concrete when the stone powder content does not exceed a certain range. The results of the study point out the direction for the quality control of concrete with machine-made sand.
机制砂取代天然砂已成为混凝土行业可持续发展的必然选择。采用正交试验和灰色关联分析研究机制凝灰岩砂混凝土的性能。通过正交试验得出机制砂混凝土的最优配合比，并对其工作性能进行了验证。应用灰色关联分析比较影响机制砂混凝土力学性能的因素。试验结果表明，砂率对坍落度和坍落扩展度的影响程度最大。矿物掺合料对混凝土7天抗压强度的影响最大。此外，水胶比对28天抗压强度的影响最大。当矿物掺合料为20%、砂率为46%、石粉含量为10%、水胶比为0.30时，机制砂混凝土的力学性能和工作性能达到最优状态。通过比较不同质量相近的细骨料混凝土，得出凝灰岩砂混凝土、石灰石砂混凝土和河砂混凝土的力学性能和工作性能相似的结论。机制混凝土的抗压强度与粗糙度的相关性最大，与石粉含量的相关性最小。当石粉含量不超过一定范围时，石粉含量对混凝土抗压强度几乎没有影响。研究结果为机制砂混凝土的质量控制指明了方向。
