不同养护环境下SAP对UHPC自愈合性能的影响  

Effect of Superabsorbent Polymer on Self-healing Performance of Ultrahigh-performance Concrete in Different Curing Environments

作　　者：邓文琴 杨在欣 刘朵 张建东[1,2] 顾建成 DENG Wen-qin;YANG Zai-xin;LIU Duo;ZHANG Jian-dong;GU Jian-cheng(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China;JSTI Group Co.Ltd.,Nanjing 210019,Jiangsu,China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816 [2]苏交科集团股份有限公司,江苏南京210019

出　　处：《中国公路学报》2025年第2期185-196,共12页China Journal of Highway and Transport

基　　金：国家自然科学基金青年科学基金项目(51908282);国家自然科学基金项目(52378160);山东省交通运输厅科技计划项目(2020B47)。

摘　　要：为了探明不同养护环境下高吸水性树脂(SAP)对超高性能混凝土(UHPC)不同宽度裂缝自愈合性能的影响,对添加不同掺量和粒径SAP的UHPC试件进行预加载制造裂缝并测量初始裂缝宽度,然后置于水浴、干湿循环及室温干燥3种环境中进行养护。从裂缝宽度的变化、力学性能的恢复、超声波速度的变化以及微观产物分析4个角度评价UHPC的自愈合效果。研究结果表明:水浴养护对UHPC裂缝愈合效果提升最好,干湿循环养护次之,室温干燥养护最差;UHPC本身具备一定的自愈合功能,在水浴环境下对于裂缝宽度小于50μm的微裂缝能够基本实现自愈合,添加SAP影响不大;对于裂缝宽度大于50μm的宏观裂缝,添加SAP可以显著提升UHPC的裂缝宽度愈合效果,在水浴养护下,宽度区间为50~150μm的裂缝可基本实现完全闭合,宽度区间为150~200μm的裂缝愈合率可达50%;SAP对UHPC的初始抗压强度影响不大,抗折强度随SAP掺量增加而减小;SAP掺量与粒径对UHPC的力学性能恢复率和超声波速恢复率的影响具有一致性,SAP粒径越小,UHPC裂缝自愈合和力学性能恢复效果越好;UHPC裂缝的愈合产物主要为碳酸钙和C—S—H凝胶,添加SAP能促进胶凝材料的水化,延长自愈合反应的持续时间,增加裂缝处愈合物质含量。Ultrahigh-performance concrete(UHPC)specimens containing different amounts and particle sizes of a superabsorbent polymer(SAP)were preloaded to induce cracking to investigate the effect of the SAP on the self-healing performance of UHPC cracks with different widths in different curing environments.The initial crack widths were measured,and the specimens were then cured in three environments:water,water-dry cycle,and room-temperature-drying environments.The self-healing effect of the UHPC was evaluated from four perspectives:changes in crack width,recovery of mechanical properties,variations in ultrasonic velocity,and microscopic product analysis.The test results show that water curing best improves the crack-healing effect of UHPC,followed by water-dry cycle curing,whereas room-temperature-drying curing was the worst.In addition,UHPC exhibits a self-healing ability.Under water and water-dry cycle curing conditions,microcracks with crack widths smaller than 50μm can basically achieve self-healing,and adding the SAP has a minimal effect.For macrocracks with crack widths exceeding 50μm,adding SAP can significantly improve the crack-width-healing effect of UHPC.Under water-cured conditions,cracks with widths of 50-150μm can be completely closed,and the healing rate of cracks with widths between 150 and 200μm can reach 50%.The SAP minimally influences the initial compressive strength of the UHPC,and the flexural strength decreases with increasing SAP content.The effects of SAP dosage and particle size on the mechanical property recovery rate and ultrasonic velocity recovery rate of UHPC are consistent.The healing products of the UHPC cracks are primarily calcium carbonate and C—S—H gel.The addition of SAP promotes the hydration of the cementitious material,prolongs the duration of the self-healing reaction,and increases the content of healing substances at cracks.

关 键 词：桥梁工程 超高性能混凝土 高吸水性树脂 裂缝宽度 裂缝自愈合 养护环境 超声波检测 

分 类 号：U444[建筑科学—桥梁与隧道工程]