钢纤维砂浆抗裂性能的定量评价与机理

Quantitative Evaluation and Mechanism of Crack Resistance of Steel Fiber Reinforced Mortar

基于图像分析技术,定量评价了钢纤维掺量、直径及形状对砂浆塑性开裂性能的影响规律。测试了相应条件下砂浆开裂时的塑性抗拉强度及随时间变化的水分蒸发速率,探讨了钢纤维的阻裂机理。结果表明:钢纤维掺量增加、直径减小,裂缝潜在参数Pcrack和尺度参数β降低,裂缝平均宽度降低,抗塑性开裂性能变好;波浪型钢纤维的抗塑性开裂性能优于平直型钢纤维;钢纤维对砂浆抗裂性能的改善主要归功于抗拉强度的提高,而与水分蒸发速率基本无关。

Based on image analysis technique,effect of content,diameter and geometry of steel fiber on plastic shrinkage cracking of mortar was quantitatively evaluated.Plastic tensile strength of mortar at the cracking time and water evaporation rate changing along with time were tested,mechanism of crack resistance of steel fiber was discussed.Results show that,with the increase of steel fiber content,the decrease of steel fiber diameter,crack potential parameter Pcrack and dimension parameter β decrease,average crack width decreases,which imply the plastic crack resistance of steel fiber improves.Plastic crack resistance of steel fiber with shape of wave is better than that with shape of flat.The improvement of crack resistance of steel fiber to mortar mainly attaches to the improvement of tensile strength,while it is essentially independent of the water evaporation rate.