基于粉煤灰的地聚合物增强混凝土梁采用碳纤维增强塑料（CFRP）加固的性能试验研究。

Experimental investigation on the behavior of fly-ash based geopolymer reinforced concrete beams strengthened with CFRP.

作者信息

Eisa Ahmed S, Ahmed Mostafa H, Demjan Ivo, Katunský Dušan

机构信息

Department of Structural Engineering, Faculty of Engineering, Zagazig University, Zagazig, 44511, Egypt.

Institute of Structural Engineering and Transportation Structures, Faculty of Civil Engineering, Technical University of Košice, Slovakia.

出版信息

Heliyon. 2023 Jun 26;9(7):e17674. doi: 10.1016/j.heliyon.2023.e17674. eCollection 2023 Jul.

DOI:10.1016/j.heliyon.2023.e17674

PMID:37539208

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10395122/

Abstract

Recently, the demand for strengthening and rehabilitation of existing RC structures has increased due to the corrosion of internal steel reinforcement, variations in temperature, and increasing loading. As a result, several experimental studies have been performed to investigate the structural behaviour of strengthening RC beams with CFRP sheets, but few for GPC beams; therefore, this investigation focuses on the behaviour of strengthening GPC beams with CFRP sheets. In this experimental work, a set of ten specimen beams with the same cross section of 100 × 250 mm and 850 mm length with a 750 mm clear span were cast in two groups of five beams each. First group (flexural group) to study the flexural behavior, and the second one for the shear behaviour (shear group). In each group, the first beam was carried out as an RC control beam and the second as a GPC control beam without strengthening, while the other three beams were cast as GPC beams and strengthened with various schemes of CFRP sheets. All specimens were tested up to failure under two-sided static loading (four-point bending). The first cracking, yielding, and ultimate failure loads, the deflection values at midspan, the longitudinal bar strain, and the concrete strain were recorded for all tested specimens. The experimental results indicated that the Flextural Strengthening of GPC with CFRP sheet increased the First Cracking, yield and ultimate load capacity by 25.33%, 15.3% and 15% respectively, as well as, deflection was decreased by 16% on average while ductility and toughness have improved by 10% and 12% on average compared to R.C Beam.On the other side, the Shear Strengthening of GPC with CFRP strips increased the First Cracking, yield and ultimate load by 43%, 70% and 68% respectively, as well as, shear ductility has improved by 8% on average compared to R.C Beam. Overall, the different schemes of externally bound CFRP sheets have improved the flexural and shear behaviour of GPC beams.

摘要

近年来，由于内部钢筋腐蚀、温度变化和荷载增加，对既有钢筋混凝土（RC）结构进行加固和修复的需求不断增长。因此，已经开展了多项实验研究来调查采用碳纤维增强塑料（CFRP）板加固RC梁的结构性能，但针对玻璃纤维增强水泥（GPC）梁的研究较少；所以，本研究聚焦于采用CFRP板加固GPC梁的性能。在本实验工作中，浇筑了一组十根试件梁，其截面均为100×250mm，长度为850mm，净跨度为750mm，分为两组，每组五根梁。第一组（抗弯组）用于研究抗弯性能，第二组用于研究抗剪性能（抗剪组）。在每组中，第一根梁作为未加固的RC控制梁，第二根作为未加固的GPC控制梁，而另外三根梁浇筑为GPC梁并用不同方案的CFRP板进行加固。所有试件在双侧静态加载（四点弯曲）下直至破坏进行测试。记录了所有测试试件的首次开裂、屈服和极限破坏荷载、跨中挠度值、纵向钢筋应变和混凝土应变。实验结果表明，与RC梁相比，采用CFRP板对GPC梁进行抗弯加固分别使首次开裂、屈服和极限承载力提高了25.33%、15.3%和15%，同时，挠度平均降低了16%，而延性和韧性平均提高了10%和12%。另一方面，与RC梁相比，采用CFRP条带对GPC梁进行抗剪加固分别使首次开裂、屈服和极限荷载提高了43%、70%和68%，同时，抗剪延性平均提高了8%。总体而言，外部粘贴CFRP板的不同方案改善了GPC梁的抗弯和抗剪性能。