水泥基材料多尺度抗裂增韧机理研究进展

Research Progress on Multi-Scale Cracking Resistance and Toughening Mechanisms for Cement-Based Materials

水泥基材料为多相多尺度结构,各组分均不同程度影响整体韧性,将相关组分按宏观、介观、纳观3个尺度分类概述其对水泥基材料的抗裂增韧机理。宏观尺度如胶凝组分、集料、外加剂、纤维、水胶比、养护制度等,分析其物化效应对水泥基材料抗裂增韧特性的影响机理;介观尺度如微珠、晶须、渗透结晶材料等微米级增强材料,阐述其火山灰、填充、桥接、键合、渗透结晶等增强效应;纳观尺度如纳米SiO_(2)、纳米CaCO_(3)、石墨烯、碳纳米管及微生物、纳米聚合物等纳米级增强材料,介绍其对水化产物微观结构、生长方式及硬化浆体孔结构的增强及优化机理;并阐述‘碳纤维+碳纳米管’、‘纤维+晶须+石墨烯’等跨尺度组分的共轭增韧效应。最后,讨论不同尺度增韧组分当前应用、研究中的不足及发展趋势。

Cement-based materials have a multi-phase and multi-scale structure,and each component forming the structure affects the overall toughness to varying degrees.This review summarized the cracking-resistance and toughening mechanisms of relevant components classified in macroscale,mesoscale and nanoscale to cement-based materials.In the macroscale(such as the cementitious component,aggregate,admixture,fiber,water-binder ratio,curing system,etc.),the influence mechanisms of the physicochemical effects of relevant components on the cracking resistance and toughening characteristics of cement-based materials were analyzed.In the mesoscale(such as microsphere,whisker,capillary crystalline material,etc.),the enhancement effects such as volcanic ash,filling,bridging,bonding,capillary crystallization were described.In the nanoscale(such as nano-SiO_(2),nano-CaCO_(3),graphene,carbon nanotube,microorganism,nano-polymer,etc.),the mechanisms enhancing and optimizing the microstructure of hydration products,growth mode,and pore structure of hardened paste were introduced.The conjugating toughening effects of cross-scale components such as‘carbon fiber+carbon nanotubes’,‘fiber+whisker+graphene’were elucidated.In addition,the shortcomings in the current application/research,and the future development trends for toughening components in different scales were also discussed.