砂胶比对纤维增强砂浆韧性及收缩性能的影响

Effect of Sand-binder Ratio on the Ductility and Shrinkage Properties of Fiber-Reinforced Mortars

文中采用四点弯曲试验、三点抗折试验以及抗压试验,研究不同砂胶比对纤维增强砂浆韧性和力学强度的影响,并进行30d的收缩量监测,研究砂胶比对砂浆总收缩量的影响规律。结果表明:增大砂胶比会导致纤维分散不均匀、减小包裹纤维的浆体的厚度,进而降低了抗弯强度、弯曲韧性以及峰值位移;增大砂胶比提高了早期抗折强但后期抗折强度下降;砂胶比大于0.5,会减小浆体体积,增加砂浆内部的空隙和缺陷,进而降低抗压强度;增大砂胶比减小了单位体积内胶凝材料的含量并增强了砂粒对水泥基胶凝材料收缩的阻碍作用,有利于降低收缩值。

Sand to binderSand to binder ratios are the key element influencing the performance of fiber reinforced mortar.In this study,fourpoint flexural test,three-point flexural test and compressivet est were conducted to study the effects of sand to binder ratois on the ductility and mechanical strength of fiber-reinforced mortar,and monitoirng of shrinkage for 30d was carried out to study the effect o sfand to binder ratios on the total shrinkage of mortar.The results show thatin creasing the sand ratio caused uneven dispersion of fibers,and reduced the thickness of the fiber-wrapped mortar,resulting in the decreaes of flexural strength,bending toughness and peak displacemen;t Increasing the sand ratio enhanced the overall skeleton effect and mechanicaol cclusion to improve the early flexural strength,but expandedt he transition zone and woke the bridging effect of fibers on cracks,which led to the decrease of flexural strength at late stage The sand ot binder ratios greater than 0.5 decreased the volume of the slurry and introduced voids and defects inside the mortar to diminish the compressive strength;Increasing the sand ratio reduced the content of cementitious material per unit volume and enhanced the hindering effect of sand particles to reduce shrinkage.