Manufactured sand (MS) is considered a reliable alternative to natural sand (NS) in concrete due to its wide availability and cost-effectiveness. In this study, the influences of water-cement ratio (0.41, 0.44, 0.47), replacement rate of MS (20 %, 60 %, 100 %) and stone powder content (0 %, 5 %, 10 %) on the mechanical and fracture characteristics of manufactured sand concrete (MSC) were investigated. Statistical model of mechanical properties (compressive strength, flexural strength and flexural toughness) of MSC was constructed based on response surface methodology (RSM). Acoustic emission (AE) technology was used to monitor the MSC fracture process in real time. The correlation between the cumulative AE parameters and the strength of MSC was analyzed. The results showed that the compressive strength, flexural strength and flexural toughness of MSC were negatively correlated with water-cement ratio while positively correlated with the replacement rate of MS. The optimum stone powder content can be determined for MSC to reach its maximum compressive strength. The coupling effects of water-cement ratio and replacement rate of MS was the most significant. This was followed by the coupling effect of water-cement ratio and stone powder content. The coupling effect of stone powder content and replacement rate of MS was the weakest. Moreover, AE analysis on the fracture process of MSC indicated that the AE parameters were more active when the water-cement ratio increased. As the replacement rate of MS increased, the AE parameters were smoother and the specimens were less damaged. The stone powder content played greater role in affecting the AE parameters in compression, while the effect of stone powder content on the four-point bending test was not significant. The cumulative AE parameters were linearly related to the strength of MSC. The cumulative AE parameters can reflect the strength of MSC.

中文翻译：

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不同替代率和石粉含量机制砂混凝土的统计模型和断裂行为


机制砂 (MS) 因其广泛的可用性和成本效益而被认为是混凝土中天然砂 (NS) 的可靠替代品。本研究研究了水灰比（0.41、0.44、0.47）、MS替代率（20%、60%、100%）和石粉含量（0%、5%、10%）对力学性能的影响。研究了机制砂混凝土（MSC）的断裂特性。基于响应面法（RSM）构建了MSC的力学性能（抗压强度、弯曲强度和弯曲韧性）统计模型。采用声发射（AE）技术实时监测MSC断裂过程。分析累积AE参数与MSC强度之间的相关性。结果表明，MSC的抗压强度、抗折强度和抗弯韧性与水灰比呈负相关，与MS的替代率呈正相关。可以确定MSC达到最大抗压强度的最佳石粉含量。水灰比与MS置换率的耦合效应最为显着。其次是水灰比和石粉含量的耦合作用。石粉含量与MS替代率的耦合效应最弱。此外，对MSC断裂过程的声发射分析表明，当水灰比增加时，声发射参数更加活跃。随着MS更换率的增加，AE参数更加平滑，试件损伤较小。石粉含量对压缩AE参数的影响较大，而石粉含量对四点弯曲试验影响不显着。 累积AE参数与MSC的强度线性相关。累积的AE参数可以反映MSC的强度。