Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the c...Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the content of microfine particle, the distribution of particle sizes, the shape features, besides the different lithological origin. From the rheological point of view, the crushed sands frequently provide mixtures with high yield stress, high viscosity, high cohesion and internal friction, which hinders its use in concrete. This study is focused on the evaluation of the rheological behavior of concrete mortar phase when using different lithological types of crushed sand in total replacement of natural sand. The lithological types surveyed were granite, calcitic limestone, dolomite limestone and mica schist. Each of these sand types was studied in two ways： in natura and with adjusted grading curve. The results show the best performance of calcitic limestone providing lower viscosities and lower yield stress in mortars.展开更多
为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为...为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为变量,进行室内连续配筋混凝土-沥青混凝土(Continuously Reinforced Concrete Pavement-Asphalt Concrete,CRCP-AC)层间同步碎石封层(Synchronous Crushed Stone Seal Coat,SCSSC)抗剪模拟试验。结合三维有限元分析结果,确定了同步碎石封层最佳参数组合,提出了改善层间抗剪强度的建议。试验结果表明:集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力对同步碎石封层层间抗剪强度产生了显著影响;相较于4.75~9.5mm粒径的集料,为获取更高的抗剪切强度,在工程实践中宜选择9.5~13.2mm粒径的碎石作为同步碎石封层用撒布料;使用粒径为9.5~13.2mm的集料时,最佳参数组合为沥青洒布量1.6kg/m^(2)+碎石撒布量8kg/m^(2)。展开更多
文摘Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the content of microfine particle, the distribution of particle sizes, the shape features, besides the different lithological origin. From the rheological point of view, the crushed sands frequently provide mixtures with high yield stress, high viscosity, high cohesion and internal friction, which hinders its use in concrete. This study is focused on the evaluation of the rheological behavior of concrete mortar phase when using different lithological types of crushed sand in total replacement of natural sand. The lithological types surveyed were granite, calcitic limestone, dolomite limestone and mica schist. Each of these sand types was studied in two ways： in natura and with adjusted grading curve. The results show the best performance of calcitic limestone providing lower viscosities and lower yield stress in mortars.
文摘为改善连续配筋混凝土与沥青面层间的黏结效果,提高复合式路面层间抗剪强度,以同步碎石封层层间抗剪强度为研究对象,采用“水泥混凝土+封层+沥青面层”的复合结构,以集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力为变量,进行室内连续配筋混凝土-沥青混凝土(Continuously Reinforced Concrete Pavement-Asphalt Concrete,CRCP-AC)层间同步碎石封层(Synchronous Crushed Stone Seal Coat,SCSSC)抗剪模拟试验。结合三维有限元分析结果,确定了同步碎石封层最佳参数组合,提出了改善层间抗剪强度的建议。试验结果表明:集料粒径、沥青洒布量、试验温度、混凝土基面构造深度、竖向压应力对同步碎石封层层间抗剪强度产生了显著影响;相较于4.75~9.5mm粒径的集料,为获取更高的抗剪切强度,在工程实践中宜选择9.5~13.2mm粒径的碎石作为同步碎石封层用撒布料;使用粒径为9.5~13.2mm的集料时,最佳参数组合为沥青洒布量1.6kg/m^(2)+碎石撒布量8kg/m^(2)。
