轻质多孔混凝土防水剂的研究进展  

A Review on Waterproofing Agent of Lightweight Porous Concrete

作　　者：周薛霞 杨赞中[1,3,4,5] 徐艳娇 王路 孙海滨 王永在[2] 杜庆洋[1] 乐红志[1] ZHOU Xuexia;YANG Zanzhong;XU Yanjiao;WANG Lu;SUN Haibin;WANG Yongzai;DU Qingyang;YUE Hongzhi(School of Materials Science and Engineering,Shandong University of Technology,Zibo 255049;Analysis and Testing Center,Shandong University of Technology,Zibo 255049)

机构地区：[1]山东理工大学材料科学与工程学院,淄博255049 [2]山东理工大学分析测试中心,淄博255049 [3]山东省高校先进复合材料重点实验室 [4]中国矿物岩石材料专业委员会 [5]山东省本科教育教学指导委员会

出　　处：《材料导报》2019年第15期2546-2551,共6页Materials Reports

基　　金：山东省科技发展计划重大专项(2014GZX201008);淄博市校城融合发展计划(2016ZBXC141);淄博市创新发展重点项目计划(2016CX16A011)~~

摘　　要：多孔混凝土具有质量轻、保温隔热、防火不燃等特性,是一种新型节能建筑材料。但多孔混凝土因孔隙率高、表面自由能大,导致其易吸水,严重影响了其强度和保温性能。因此,多孔混凝土的防水问题亟需研究解决。多孔混凝土的防水研究主要集中在两个方面:一是基体结构优化,二是利用防水剂改性。基体结构优化主要通过改善混凝土的孔结构及孔间壁的晶胶比,以降低其吸水性。由于基体结构优化的防水效果有很大的局限性,因此通过防水剂改性提高多孔混凝土防水性能的研究更受关注。防水剂在多孔混凝土表面或在气孔和毛细孔内形成疏水膜层,由此可降低混凝土的吸水性或是静水压力下的透水性。常用的防水剂为有机硅类、脂肪酸盐类及石蜡乳液类等。有机硅系主要通过长链有机基团取代,以获得具有良好疏水性的端基。脂肪酸盐系通过羧酸基与Ca 2+形成“反毛细管效应”的沉淀物,或者是活性物质与基体结合,阻塞孔道而防水;石蜡乳液则通过对颗粒物形成包裹,使其表面由亲水性转化为憎水性,由此降低吸水率。防水剂的作用方式分为两种:一是防水剂对基体表面的隔离,包括封闭型和开放型;二是防水剂与基体的结合,包括反应型和结合型。多孔混凝土的防水方法主要有两种:一是在表面涂覆、浸渍或喷涂防水剂的表面防水;二是在混凝土制备过程中掺加防水剂的内掺防水。表面防水效果因防水剂的渗透深度不同而异,与混凝土连通孔的比例、孔隙率的大小及防水剂的粘度和表面张力有关。内掺防水受防水剂的类型及其与硅酸盐基体的相容性等影响较大。但从防水的持久性和综合效果方面考量,内掺防水法更具优势。目前,主要通过吸水率、氯离子渗透系数和静态水接触角测量等方法来表征与评价多孔混凝土的防水效能,这方面的研究相对滞�Porous concrete is a novel energy-saving building material,which features light weight,excellent thermal insulation,outstanding fire resis-tance and non-combustibility.However,it suffers a severe water-absorbing problem due to its high porosity and high surface free energy.The issue,degrading seriously the strength and thermal insulation properties,restrains their further applications.Therefore,it is imperative to address the waterproof problem of the porous concrete.The matrix structure optimization and water repellent modification are two primary directions in current waterproof researches.The matrix structure is optimized by adjusting of the pore structure of the concrete and the crystal/gel ratio of pore walls to reduce the water absorption of concretes.Yet,the waterproof performance,achieved by the optimization of matrix structure,exhibits severe limitations.Hence,the method of the waterproofing agent modification to improve the waterproof performance gains more attentions.The water repellent accomplishes the reduction of water absorption of the concrete or the water permeability under hydrostatic pressure through forming a hydrophobic film on the surface of porous concretes and/or in pores.Commonly,water repellents consist of silicones,fatty acid salts and paraffin emulsions.The silicone system achieves a good hydrophobicity via the substitution of long-chain organic group.The waterproof performance of the fatty acid salt is obtained by two methods:(ⅰ)forming a precipitate,which shows“anti-capillary effect”,by the reaction of carboxylic acid group and Ca 2+;or(ⅱ)blocking pores through the active substance,which binds to the matrix.The paraffin emulsion achieves the reduced water absorption property through converting the surface property of particles from hydrophilicity into water repellency by encapsulation.The action mode of the water repellent includes two types.One is the isolation of the substrate’s surface,including the closed-type and the opened-type.The other is the combination with the ma

关 键 词：多孔混凝土 防水剂 防水机理 防水改性 体积憎水法 表征与评价 

分 类 号：TU528[建筑科学—建筑技术科学]