聚丙烯纤维参数对水泥砂浆抗干缩开裂性的影响

利用圆环法测试研究了聚丙烯纤维掺量、长度、几何形状等参数对水泥砂浆在硬化阶段抗干缩开裂性能的影响．实验结果表明：三叶形聚丙烯单丝纤维的掺加能明显改善水泥砂浆在硬化阶段的抗干缩开裂性能，且其掺加的量越多，水泥砂浆的抗干缩开裂性越好；聚丙烯纤维横截面形状不同，其对水泥砂浆抗干缩开裂性的作用效果也不同，其中横截面为三叶形的聚丙烯单丝纤维对水泥砂浆抗干缩开裂性的作用效果较好；掺入的三叶形聚丙烯单丝纤维长度越长，水泥砂浆的抗干缩开裂性越好；三叶形聚丙烯单丝纤维经表面处理后，其对水泥砂浆抗干缩开裂性的影响有所增大．

Effects of Characteristics of Polypropylene Fiber on Anti-dry-shrinkage Cracking Property of Cement Mortar

The effects of volume fraction, length and geometric shape of polypropylene fiber on the anti-dry-shrinkage cracking property of cement mortar were tested by the ring test method. The experimental results show that trefoil polypropylene filament fiber can obviously increase the anti-dry-shrinkage cracking property of cement mortar in hardening stage. The more the fiber is mixed, the better the anti-dry-shrinkage cracking property of cement mortar are improved. Polypropylene fibers with different shapes of cross-section have different effects on the anti-dry-shrinkage cracking of cement mortar. The cracking width of cement mortar reinforced by polypropylene fiber with trefoil cross-section is smaller. The longer the length of trefoil polypropylene filament fiber, the better the anti-dry-shrinkage cracking property of cement mortar. The mortars reinforced by trefoil polypropylene filament fibers treated with different surface-modifications have better anti-dry-shrinkage cracking property, in which the anti-dry-shrinkage cracking property of cement mortar reinforced by the polypropylene fiber treated with oxidant is best.