掺入钢纤维对混凝土塑性收缩开裂的影响研究

Experimental Study of Shear Strength of Brick Masonry Walls Assembled with Different Types of Mortar

混凝土在干燥环境中会产生自然收缩,当收缩受到抑制时产生张应力,从而产生塑性收缩裂缝.为了减少混凝土塑性收缩开裂,通过在混凝土中添加3种不同体积、不同长径比的钢纤维,在56 MPa和73 MPa两种不同抗压强度水平下进行了塑性收缩实验,对纤维体积和钩型钢纤维的长径比对混凝土塑性收缩开裂及其它性能的影响进行了研究.结果表明:掺入钢纤维可以显著增强混凝土的抗塑性收缩开裂性能,总塑性收缩裂纹面积与纤维体积之间存在较好的对应关系,但掺入钢纤维在新拌和硬化状态下会对混凝土某些其它性能产生不利影响.

Concrete undergoes natural shrinkage in a dry environment,and when shrinkage is suppressed,tensile stress is generated,resulting in plastic shrinkage cracks.In order to reduce plastic shrinkage cracking of concrete,plastic shrinkage experiments were conducted by adding three types of steel fibers with different volumes and length to diameter ratios to concrete at two different compressive strength levels of 56 MPa and 73 MPa.The effects of fiber volume and length to diameter ratio of hooked steel fibers on plastic shrinkage cracking and other properties of concrete were studied.The research results indicate that the addition of steel fibers can significantly enhance the plastic shrinkage cracking resistance of concrete.There is a good correspondence between the total plastic shrinkage crack area and fiber volume,but the addition of steel fibers in the newly mixed and hardened state can have adverse effects on certain other properties of concrete.