PP/PVA纤维增强硫铝酸盐水泥基快速修补材料试验研究

针对交通压力增大,公路桥梁路面易出现疲劳破坏的问题,提出以聚丙烯(PP)纤维与聚乙烯醇(PVA)纤维提升硫铝酸盐水泥基快速修补材料性能。分别探究了PP纤维与PVA纤维单掺及复掺对硫铝酸盐水泥基快速修补材料流动度、强度以及韧性的影响,并进一步研究了最优复掺比例对修补材料粘结强度及体积稳定性的影响。结果表明:单掺PP纤维对修补材料砂浆流动度影响较小,并且能显著提升抗折强度,掺入0.2%(体积分数,下同)的PP纤维流动度仅下降4%,1 d和28 d抗折强度分别达到了12.8 MPa、15.5 MPa。单掺PVA纤维会大幅减小修补材料砂浆流动度,提升抗压强度,掺入0.2%的PVA纤维流动度下降21%,1 d和28 d抗压强度分别达到了56.6 MPa、84.3 MPa。当PP和PVA纤维按3:1的比例,以0.2%的总体积掺量进行复掺时,两种纤维可以发挥协同作用使修补材料不仅可以获得良好的流动性能、强度与韧性,同时获得较好粘结强度与体积稳定性。28 d时修补材料砂浆的粘结强度达到5.6 MPa,干燥收缩率低至2.73×10^-4,可以更好地满足公路桥梁路面、伸缩缝的快速修补需求。

PP/PVA Fiber Reinforced Sulphoaluminate Cement-Based Rapid Repair Material

With the increase of traffic pressure, the road surface of highways and bridges is prone to fatigue failure. In this paper, polypropylene (PP) fiber and polyvinyl alcohol (PVA) fiber are used to improve the properties of sulphoaluminate cement-based rapid repair material. The effects of single and compound PP and PVA fibers on fluidity, strength and toughness of sulphoaluminate cement-based rapid repair materials were investigated, and the effects of the optimal mixing ratio on the bonding strength and volume stability of the repair materials were also studied. The results show that the single PP fiber has little effect on the fluidity of mortar, and significantly improves the flexural strength. After adding 0.2% (volume fraction, the same below) PP fiber, the fluidity only decreases by 4%, and the 1 d and 28 d flexural strengths reach 12.8 MPa and 15.5 MPa, respectively. The single addition of PVA fiber significantly reduces the fluidity of mortar repair materials and enhances the compressive strength. The fluidity of mortar decreases by 21% with the addition of 0.2% PVA fiber, and the 1 d and 28 d compressive strength reach 56.6 MPa and 84.3 MPa, respectively. When the ratio of PP and PVA fibers is 3:1 and the total volume content is 0.2%, the two kinds of fibers play a synergistic role to make the quick repair material not only obtains good flow performance, strength, and toughness, but also improves the bonding performance and shrinkage characteristics of mortar. At 28 d, the mortar bonding strength reaches 5.6 MPa, and the drying shrinkage rate is 2.73×10^-4, which better meets the rapid repair needs of highways and bridges pavement and expansion joints.