丙烯酰胺单体聚合复合硅灰石晶须协同增韧混凝土  

Synergistic Toughening Mechanism of Concrete Based on Polymerization of Acrylamide Monomer and Wollastonite Whisker

作　　者：徐洁 汤金辉 高畅 王瑞 王文彬 孟振亚 刘加平[1] XU Jie;TANG Jinhui;GAO Chang;WANG Rui;WANG Wenbin;MENG Zhenya;LIU Jiaping(School of Material Science and Engineering,Southeast University,Nanjing 211189,China;State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Sobute New Materials Co.Ltd.,Nanjing 211103,China)

机构地区：[1]东南大学材料科学与工程学院,南京211189 [2]江苏苏博特新材料股份有限公司,高性能土木工程材料国家重点实验室,南京211103

出　　处：《硅酸盐学报》2024年第2期533-544,共12页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金青年基金(52108197);科技部十四五重点研发项目(2021YFF0500802)。

摘　　要：现代混凝土由于其物相组成复杂、多尺度效应等原因,导致其脆性大、韧性差。采用丙烯酰胺(AM)单体原位聚合协同硅灰石晶须(CS)的改性方法开展了对混凝土基体增韧的研究。通过多种测试手段对水泥硬化浆体的物相组成和微观结构进行表征,结果表明:AM原位聚合协同CS能够显著提升混凝土的抗弯能力,28d抗弯应力峰值和断裂能分别提高31.5%和91.4%,且抗压强度基本保持不变。CS晶须可以促进水泥水化,发挥填充效应,降低孔隙率;AM聚合能够在水泥浆体中构筑塑化区,弱化混凝土内部应力集中;二者的协同作用可以增强水化产物间的胶结力,形成有机-无机互穿的网络结构,跨尺度优化混凝土的结构,为混凝土基体增韧提供新的理论与技术。Introduction Conventional concrete is a porous heterogeneous quasi-brittle material,which has some problems such as poor toughness,low flexural tensile strength and poor durability,and cannot meet the needs of modern construction for high strength,high crack resistance and high durability of concrete materials.The existing methods used to toughen concrete are fiber reinforcement and matrix toughening.Among them,fiber is an extrinsic toughening.The toughness of cement matrix can be improved with polymers and nanomaterials.In addition,compared with mixing polymers directly,the modified method of in-situ polymerization of organic monomers can improve the flexural strength of cement pastes.However,the effect and mechanism of this method on toughening concrete are still unclear.Therefore,the effect of in-situ polymerization of acrylamide(AM)monomer and wollastonite(CS)whisker on the mechanical properties,hydration heat release,phase composition and microstructure of concrete were investigated to provide an idea for toughening concrete matrix.Methods Raw materials were P·Ⅱ52.5 Portland cement,quartz sand with the fineness modulus of 2.6-2.9 and basalt with the particle sizes of 5-16 mm.The composite modified materials used were all adscititious,in which an organic monomer was acrylamide(AM),an initiator was ammonium persulphate(APS),and a crosslinking agent was N,N'-methylenebisacrylamide(MBA).The inorganic modified material was wollastonite(CS)whisker,and its micromorphology was dense and short rod fibrous.The water-cement ratios(W/C)of concrete and cement paste were 0.47 and 0.40,respectively.The dosages of CS were 1%(in mass fraction),2% and 4% by the mass of cement.The dosages of AM were 3% and 5% by the mass of cement,the dosages of APS were 3% and 5% by the mass of AM,and the dosage of MBA was 0.1% by the mass of AM.The compressive strength,flexural stress-strain curve and fracture energy of concrete specimens(100 mm×100 mm×100 mm and 100 mm×100 mm×400 mm)were tested after curing under standard curing cond

关 键 词：丙烯酰胺单体聚合 硅灰石晶须 混凝土 力学性能 水化 微观结构 

分 类 号：TU528[建筑科学—建筑技术科学]