碾压橡胶混凝土的强度特性

Strength Characteristics of Roller Compacted Rubcrete

采用橡胶粉等体积代砂方法,研究了碾压混凝土掺入橡胶粉后的工作性和抗压强度的变化规律,回归得出了碾压橡胶混凝土强度公式,探讨了等抗压强度(40,MPa)条件下橡胶粉用量对碾压混凝土轴拉强度和极限拉伸值的影响.试验水灰比为0.30～0.55,橡胶粉用量为50～120 kg/m3.试验结果表明:橡胶粉颗粒在碾压混凝土试件中均匀分布,振实过程中不会出现颗粒上浮问题;橡胶粉等体积代砂,不会对混凝土的工作性产生显著影响;水泥强度、水灰比和橡胶粉用量是影响碾压混凝土强度的主要因素,橡胶粉用量与抗压强度降低幅度之间具有近似线性关系;在碾压混凝土中掺入橡胶粉,有助于提高其抗拉强度和极限拉伸值,提高幅度随橡胶粉用量的增加而增大.

The workability and the strength characteristics of roller compacted rubcrete （RCR） were experimentally studied by replacing portion of sand with the same volume of tire rubber particles to get the compressive strength formula developed by regression analysis, and the effects of rubber content on the axial tensile strength and ultimate tensile elongation were investigated by keeping the compressive strengths of all specimens at the same level of 40 MPa. The water-cement ratio used was 0.30 -- 0.55, and the rubber content was 50 -- 120 kg/m^3. Test results show that the rubber particles homogeneously distribute in the RCR; no rubber particle emersion is observed during the vibrating compaction; the workability of RCR is slightly influenced by replacing portion of sand with the same volume of tire rubber particles; cement strength, water-cement ratio and rubber content are three dominant factors determining the strength of RCR; the reduction of RCR compressive strength is approximately linearly related to the rubber content; the incorporation of the rubber is helpful for enhancing the tensile strength and ultimate tensile elongation of RCR, the more the rubber, the higher the tensile strength and ultimate tensile elongation.