机制砂颗粒形状对砂浆流变性能的影响研究

Study of the Effect of Manufactured Sand Particle Shape on Mortar Rheological Property

为研究机制砂颗粒形状对砂浆流变性能的影响,使用数字图像处理技术(DIP)对砂颗粒形状进行了定量表征,设计试验测量了砂浆流变曲线并计算了砂浆屈服应力与表观黏度。结果表明,机制砂的长宽比(E)、宽高比(F)比天然河砂分别大14%、18%,说明机制砂棒状和片状程度高于天然河砂;砂浆流变曲线反映出砂颗粒形状不规则会导致砂浆流动阻力增大,在高体积分数下更为显著;根据Chateau模型拟合40%体积分数机制砂砂浆屈服应力是天然河砂的1.5倍;砂浆表观黏度分析发现,机制砂砂浆表观黏度大于天然河砂,在低剪切速率下尤其明显。

To study the effects of manufactured sand shape on mortar rheology property, the digital image processing(DIP) method was used to characterize sand particle shape quantitatively, tests of mortar rheology curve were performed and its yield stress was calculated by rheology test. Results show that E of manufactured sand(MS3) is 14% bigger than that of river sand(RS), F of MS2 is 18% bigger than that of RS, consequently, so particle shape of MS is more elongate and flat than that of RS. Besides, rheology curve results show that the irregular shape sand will increase resistance when mortar flowing, and the effect becomes more significant with sand volume increasing. Based on Chateau model, it′s predicted that for 40% sand volume mortar, yield stress of MS3 is 1.5 times as RS due to its irregular sand shape of MS3.