短切纤维及预应力对玄武岩织物增强水泥基复合材料拉伸力学性能的影响

通过静态拉伸试验研究不同体积掺量的短切碳纤维、钢纤维、耐碱玻璃纤维及预应力对5层玄武岩织物增强水泥基复合材料(BTRC)拉伸性能的影响。试验结果表明:短切碳纤维、玻璃纤维可以提高基体和BTRC的开裂强度,且开裂强度随着碳纤维掺量的增加而增加;预应力使基体产生预压力,明显提高其开裂强度。短切纤维及预应力都显著提高BTRC的峰值荷载和韧性,但峰值应变基本不变;峰值荷载和韧性随着钢纤维掺量的增加而增加,体积分数为1.5vol%掺量时达到最大值;随着碳纤维掺量增加,峰值荷载和韧性先增加后减小,体积分数为1.0vol%掺量时最大。施加预应力且掺入短切碳纤维或钢纤维时,短切纤维增强的基体可以更好地承受张拉力释放后纤维束径向变形引起的环向应力,进一步提高了织物与基体界面的挤压作用力及摩擦力,从而增强效果最明显,峰值荷载分别增加50.4%和58.9%,韧性分别增加84.7%和79.5%。BTRC材料掺入短切玻璃纤维、钢纤维及施加预应力均可以增加其受力后的裂缝条数,减小裂缝间距和裂缝宽度。

Effect of short fibers and prestress on the tensile mechanical properties of basalt textile reinforced cementitious matrix composite

The quasi-static tensile tests were conducted to investigate the effects of various volume contents of short carbon fiber,steel fiber,alkali-resistant glass fiber and prestress on the tensile performance of 5 layers basalt textile reinforced cementitious matrix composite (BTRC).The experimental results indicate that short carbon and glass fibers can increase the crack stresses of both matrix and BTRC,which increase with increasing volume fraction of short carbon fibers.The applied prestress induces compressive stress in the cementitious matrix,such that the crack stress of BTRC is improved significantly.Both the short fibers and prestress can increase ultimate load and toughness,while the ultimate strain does not change significantly.Both the ultimate load and toughness increase with increasing steel fibers content and reach the maximum values at 1.5vol% volume fraction,while both proper-ties firstly increase and then decrease with increasing content of carbon fibers with the maximum values at 1.0vol%volume fraction.When the short carbon or steel fibers are added into the matrix with prestress,the short fiber rein-forced matrix can better bear the hoop stress caused by the radial expansion of the yarns in textile after releasing the tension.So the contact and frictional forces between the textile and matrix are improved,leading to the most pro-nounced increase in ultimate load and toughness,as much as 50.4% and 58.9%,respectively,and in toughness as much as 84.7% and 79.5%,respectively.By adding short glass fiber,steel fiber and applying prestress to the BTRC composite,the crack numbers increase with smaller crack spacing and opening in the matrix.