FRP网格增强ECC拉伸本构关系研究进展

Research progress on the tensile constitutive relation of FRP grid reinforced engineered cementitious composites

相较于传统的织物增强砂浆(TRM),FRP网格增强ECC复合材料(FRP网格-ECC)由于具有更好的抗裂性和韧性,在既有砌体结构修复领域得到了较为广泛的应用。本文主要结合国内外学者在FRP网格-ECC拉伸性能方面所开展的试验研究工作,对FRP网格-ECC拉伸本构(应力-应变)关系研究进展进行了汇总与分析。结果表明:FRP网格-ECC的拉伸应力-应变关系通常以首次开裂为转折分为两个阶段,主要由2个关键点和4个参数控制。在弹性未开裂阶段,应力由ECC和FRP网格共同承担,斜率主要取决于FRP网格-ECC的复合弹性模量,开裂应变主要取决于ECC的开裂应变;在应变强化阶段,应力主要由FRP网格承担,斜率主要取决于FRP网格的弹性模量和配置率,极限拉伸应变主要由FRP网格单向拉伸极限应变确定。

Compared with the traditional textile reinforced mortar(TRM),FRP grid reinforced engineered cementitious composites(FRP grid-ECC)have been widely used in the retrofitting field of existing masonry structures due to its better crack resistance and toughness.In this paper,the research progress on tensile constitutive(stress-strain)relationship of FRP grid-ECC is summarized based on the experimental research work carried out by domestic and foreign scholars.The results show that the tensile stress-strain relationship of FRP grid-ECC is usually divided into two stages with the first crack as the turning point,which are mainly controlled by two key points and four parameters.In the elastic uncracked stage,the stress is shared by the ECC and the FRP grid,the slope mainly depends on the composite elastic modulus of the FRP grid-ECC,and the cracking strain mainly depends on the cracking strain of the ECC.In the strain strengthening stage,the stress is mainly borne by the FRP grid,and the slope mainly depends on the elastic modulus and configuration rate of the FRP grid.The ultimate tensile strain is mainly depends on the unidirectional tensile limit strain of the FRP grid.