Tang Yu, Qiu Weichao, Liu Dunwen, Zhang Wanmao, Zhang Ruiping
School of Resources and Safety Engineering, Central South University, Changsha 410083, China.
Road & Bridge North China Engineering Co., Ltd., Beijing 101100, China.
Materials (Basel). 2022 Jul 10;15(14):4817. doi: 10.3390/ma15144817.
Machine-made sand is gradually replacing natural sand to achieve sustainable development. Experimental studies and gray-correlation analysis were used to study the properties of tunnel slag machine-made mortar and concrete. The properties of machine-made mortar with different stone powder content were analyzed through experiments. By analyzing the performance of machine-made sand concrete with equal amounts of cement replaced by stone powder, the optimum replacement ratio is obtained. Gray-correlation analysis was used to compare the degree of influence of fineness modulus and stone powder content on the performance of concrete. Scanning electron microscopy (SEM) and X-ray diffractometry (XRD) were used to analyze the microstructure of tunnel slag sand concrete. The test results showed that the flexural and compressive strengths of the machine-made sand concrete were greater than the standard sand with the same stone powder content. The 28-day flexural and compressive strengths had a maximum difference of more than 30%. The best stone powder content of the machine-made mortar is in the range of 5% to 8%. When the replacement cement content of stone powder is about 6%, the mechanical and working properties of machine-made sand concrete achieve the optimal state. The lower the stone powder content, the closer the mechanical and working properties of machine-made sand concrete and river sand concrete. The correlation between the performance of machine-made sand concrete and fineness modulus is the largest. When the stone powder content is low, it has almost no effect on the compressive strength of concrete. The results point out the direction for the quality control of tunnel slag machine-made sand concrete.
机制砂正逐渐取代天然砂以实现可持续发展。采用试验研究和灰色关联分析来研究隧道矿渣机制砂浆和混凝土的性能。通过试验分析了不同石粉含量的机制砂浆性能。通过分析用石粉等量替代水泥的机制砂混凝土性能，得出最佳替代率。利用灰色关联分析比较细度模数和石粉含量对混凝土性能的影响程度。采用扫描电子显微镜（SEM）和X射线衍射仪（XRD）分析隧道矿渣砂混凝土的微观结构。试验结果表明，相同石粉含量下，机制砂混凝土的抗折强度和抗压强度均大于标准砂。28天抗折强度和抗压强度最大差值超过30%。机制砂浆的最佳石粉含量范围为5%至8%。当石粉替代水泥含量约为6%时，机制砂混凝土的力学性能和工作性能达到最佳状态。石粉含量越低，机制砂混凝土与河砂混凝土的力学性能和工作性能越接近。机制砂混凝土性能与细度模数的相关性最大。当石粉含量较低时，对混凝土抗压强度几乎没有影响。研究结果为隧道矿渣机制砂混凝土的质量控制指明了方向。
