论文部分内容阅读
研究了不同橡胶粉等体积取代砂量对喷射混凝土抗压强度、抗折强度、劈裂抗拉强度以及断裂时变形量的影响,并分析了产生这些影响的原因与机理。研究表明:喷射混凝土28 d抗压强度在橡胶粉取代砂量不超过10%时,均有一定程度的提高,超过10%时,各龄期的抗压强度呈下降趋势。抗折强度随橡胶粉取代砂量的增加先增加后减小;劈裂抗拉强度在橡胶粉掺量不超过10%时均有所增加,在10%~15%时变化不大,超过15%时劈裂抗拉强度降低;喷射混凝土的断裂时变相量在橡胶粉掺量为等体积取代砂量不超过15%时均有所增加,掺量超过15%时有小幅下降;橡胶粉的合适掺量为等体积取代砂量的5%~10%。橡胶粉改善喷射混凝土性能的原因是橡胶粉的掺加使得喷射混凝土断裂形式由脆性断裂转变为韧性断裂。
The effects of volume of sand replaced by different rubber powders on the compressive strength, flexural strength, splitting tensile strength and the amount of deformation at break of shotcrete were studied. The causes and mechanism of these effects were analyzed. The results show that the compressive strength of shotcrete at 28 d has a certain degree of increase when the amount of rubber powder replaced sand does not exceed 10%, and the compressive strength at various ages shows a downward trend when the compressive strength of shotcrete exceeds 10%. The flexural strength first increases and then decreases with the increase of the amount of sand replaced by rubber powder. The splitting tensile strength increases when the content of rubber powder does not exceed 10%, and changes little from 10% to 15% %, The splitting tensile strength decreases; when the shotcrete is broken, the amount of phase change increases when the amount of rubber powder is equal to or less than 15% when the volume of sand is replaced by an equal volume, and slightly decreases when the amount of rubber exceeds 15% Appropriate volume for the volume of sand to replace the volume of 5% to 10%. The reason that the rubber powder improves the performance of shotcrete is that the mixing of rubber powder causes the fracture mode of shotcrete to change from brittle fracture to ductile fracture.