Influence of PVA fiber on mechanical properties and durability of high toughness repair mortar
To further enhance the durability of high-toughness repair mortar under aggressive environ-mental conditions,this study investigates the effects of Polyvinyl Alcohol(PVA)fibers on the me-chanical properties and durability of high-toughness repair mortar,along with the underlying micro-scopic mechanisms.First,high-toughness repair mortar specimens with PVA fiber contents of 0.0%,0.5%,1.0%,1.5%,and 2.0%are prepared and cured under standard conditions for 3 and 28 days.Their compressive strength,flexural strength,bond strength,shrinkage performance,and frost resis-tance are evaluated.Subsequently,composite specimens of high-toughness repair mortar with varying PVA fiber contents are fabricated.The compressive and flexural strengths of these specimens are evaluated undergoing a 56 days period of wet-dry cycling.Finally,mercury intrusion porosimetry and scanning electron microscopy are employed to characterize the pore structure and micro-morphology of the mortar.Results indicate that with increasing PVA content,the compressive strength of the mortar initially increase and then basically stabilizes,while the flexural strength and bond strength gradually increase.The frost resistance rises initially but slightly declines at higher PVA contents.In a sulfate-rich environment,PVA fibers act as bridges and modify the pore structure,mitigating expansion stress caused by ettringite and other erosion products filling the pores,thereby enhancing the mortar's erosion resistance.However,when the PVA fiber volume reaches 2.0%,excessive filling of erosion products induces microcracks in the matrix,and compressive strength corrosion resistance coefficient ceases to improve.
万方数据
维普
