The purpose of this investigation is to investigate the axial and lateral behavior of low strength concrete confined by glass fiber reinforced polymer (GFRP) wraps. A total of 48 cylindrical samples having 150 mm diameter and 300 mm height were strengthened and examined. The mix designs were provided with four different target strength (5, 10, 15, and 20 MPa). The axial and lateral strain were studied to evaluate the axial strain relation and the lateral strain for axial compression. The results of this investigation present a comparison between the nine models previously reported for normal strength concrete and the lesser-known context of low strength concrete confined by fiber reinforced polymer (FRP) composites. The results obtained from this study show that the majority of models reported for normal strength concrete, can accurately predict the stress improvement ratio for low strength concrete (LSC), however, one of the models exactly predicts the strain improvement ratio for all ranges of LSC. The results also show that an increase in compressive strength of concrete causes a decrease in both stress improvement ratio and strain improvement ratio. The analysis of variance (ANOVA) was applied to study the percentage effect of the key criteria to the stress improvement ratio, strain improvement ratio, and the strain factor of LSC, where the results reveal that the compressive strength is a more effective criterion on the stress and strain improvement ratios and the strain factor than the confinement level (number of GFRP layers). Finally, lateral strain-axial strain behavior of GFRP and actively confined concrete is compared and it is understood that lateral strain- axial strain behavior of confined specimens is affected by lateral pressure and unconfined concrete strength.

这项研究的目的是研究玻璃纤维增​​强聚合物包裹的低强度混凝土的轴向和侧向性能。总共对48个直径为150毫米，高度为300毫米的圆柱形样品进行了强化和检查。混合物设计具有四种不同的目标强度（5、10、15和20 MPa）。研究了轴向和横向应变，以评估轴向应变关系和轴向压缩的横向应变。这项研究的结果提供了以前报道的用于普通强度混凝土的九种模型与由纤维增强聚合物（FRP）复合材料限制的鲜为人知的低强度混凝土之间的比较。这项研究得出的结果表明，大多数模型报告的是普通强度混凝土，可以准确预测低强度混凝土（LSC）的应力改善率，但是，其中一种模型可以准确预测所有LSC范围内的应变改善率。结果还表明，混凝土抗压强度的增加引起应力改善率和应变改善率的降低。应用方差分析（ANOVA）研究关键标准对LSC应力改善率，应变改善率和应变因子的百分比影响，结果表明抗压强度是对LSC的更有效判据。应力和应变的改善率和应变系数要高于限制水平（GFRP层数）。最后，