BFRP网格增强水泥砂浆永久模板力学与协同工作性能试验研究

Experimental study on mechanical and cooperative work performance of BFRP grid reinforced cement mortar permanent formwork

针对现有永久模板成本高和耐久性差的问题,采用轻质高强的玄武岩纤维增强复合材料(BFRP)网格增强水泥砂浆制成薄板,作为混凝土的永久模板,并开展拉伸试验,研究其力学性能。模板经过界面处理后,上部浇筑混凝土短梁,开展四点弯曲试验,研究其与混凝土的协同工作性能,研究的参数包括网格的厚度和短切纤维掺量。结果表明:BFRP网格可在薄板开裂后继续承载,较大程度地提高薄板的极限拉伸承载力,而短切纤维的掺入则能增强薄板的抗裂性能;经过打磨处理和涂刷界面剂后,永久模板与现浇混凝土界面黏结可靠,并且表现出良好的协同受力性能;永久模板的使用使构件的力学性能提升显著,破坏时挠度大幅度提升,构件可获得较好的延性。

Based on the existing problems of the high cost and poor durability permanent formwork,lightweight and high-strength basalt fiber reinforced polymer(BFRP)grid reinforced cement mortar was used to make thin plates as permanent formwork of concrete.The tensile test was carried out to study its mechanical properties.After the interface treatment,the upper part of the formwork was poured into the concrete short beam,and the four-point bending test was carried out to study the cooperative work performance between the formwork and concrete short beam.The parameters studied including the thickness of the grid and the incorporation content of chopped fibers.Results showed that the BFRP grid could continue to bear the load after the cracking of the thin plate,which greatly improved the ultimate tensile bearing capacity of the thin plate,and the addition of chopped fibers enhanced the crack resistance of the thin plate.After polishing and brushing the interface agent,the bonding between the permanent framework and the cast-in-situ concrete interface was reliable,and it showed good synergistic mechanical properties.The use of permanent formwork improved the mechanical properties of the component significantly,and the deflection was greatly improved when the failure occurred,and the component obtained better ductility.