橡胶粉对喷射混凝土性能的影响

Effect of Rubber Powder on Properties of Shotcrete

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。

We study the impact of using different rubber powder volume to replace the amount of sand on the deformation amount of sprayed concrete compressive strength,flexural strength,splitting tensile strength and fracture,and analyze the causes and mechanisms of these effects.Studies have shown that 28d compressive strength of shotcrete replaced has a certain degree of improvement when the rubber powder sand does not exceed 10%,and the compressive strength of each age shows a downward trend when rubber powder sand exceeds 10%.Flexural strength increases with the amount of rubber powder to replace sand after the first increases and then decreases;splitting tensile strength increases when the amount of silt in the rubber does not exceed 10%,little changes at 10% to 15%,decreases more than 15%; the amount of concrete in disguise increases slightly when the rubber powder sand content is replaced by an equal volume of not more than 15%,and declines when the content exceeds 15%; suitable rubber powder content is substituted with an equal volume of 5% to 10% of the amount of sand.Reason for improving the performance of rubber powder sprayed concrete is to make mixing rubber powder sprayed concrete form by the fracture toughness of brittle fracture transition to fracture.