砖混建筑垃圾制备蒸压加气混凝土性能及水化机理  

Properties and Hydration Mechanism of Autoclaved Aerated Concrete Prepared by Waste Concrete and Waste Clay Brick

作　　者：陈永亮[1,2] 成亮 陈铁军 陈君宝[1] 张轶轲 夏加庚 CHEN Yongliang;CHENG Liang;CHEN Tiejun;CHEN Junbao;ZHANG Yike;XIA Jiageng(College of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Wuhan University of Science and Technology,Wuhan 430081,China;Ushin Jiangsu Engineering Technology Co.,Ltd.,Suzhou 215000,Jiangsu,China)

机构地区：[1]武汉科技大学资源与环境工程学院,武汉430081 [2]国家环境保护矿冶资源利用与污染控制重点实验室,武汉430081 [3]泳锌江苏工程技术有限公司,江苏苏州215000

出　　处：《材料导报》2024年第12期122-127,共6页Materials Reports

基　　金：湖北省重点研发计划(2022BCA062);国家环境保护矿冶资源利用与污染控制重点实验室开放基金(HB201913);国家自然科学基金(41102218)

摘　　要：以砖混建筑垃圾为主要原料制备蒸压加气混凝土(AAC),考察了废弃混凝土(WC)、废弃黏土砖(CB)及其复配掺量对蒸压加气混凝土抗压强度和干体积密度的影响,并利用X射线衍射(XRD)和扫描电子显微镜(SEM)分析了不同砖混配比加气混凝土样品的物相组成和微观形貌。结果表明,当建筑垃圾的掺量为50%~60%(质量分数,下同)时,以废弃混凝土或废弃黏土砖为原料制备的蒸压加气混凝土的抗压强度和干体积密度均能达到《蒸压加气混凝土砌块》(GB11968-2020)中A5.0 B07级别的要求。复配能进一步提升样品性能,随着废弃混凝土、废黏土砖质量比(m(WC)∶m(CB))的降低,所得样品的抗压强度不断升高,而干体积密度先降低后上升,当质量配比为2∶3~3∶2时,试样性能达到《蒸压加气混凝土砌块》(GB11968-2020)中A5.0 B06级别的要求。蒸压养护过程中,坯体中的SiO_(2)、Al_(2)O_(3)、Ca(OH)2、长石、富钙型水化硅酸钙(α-C_(2)SH)共同作用,生成大量片状托贝莫来石、半结晶的CSH(I)、CSH凝胶和少量水化石榴石、硬石膏,与原料中残留的石英、方解石一起填充在孔壁中,相互交织成网状,提高样品强度的同时降低其密度。砖混复配的样品含有更多结晶完整的托贝莫来石、CSH(I)以及适量的CSH凝胶,形成良好的网状致密结构,使样品综合性能更优。The autoclaved aerated concrete(AAC)was prepared with waste concrete(WC)and waste clay bricks(CB)as the main raw materials.The influences of WC,CB and compound addition amounts on the compressive strength and dry bulk density of autoclaved aerated concrete were studied.The phase compositions and microscopic morphology of the AAC samples were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).The results showed that the compressive strength and dry bulk density of the AAC prepared with WC or CB,respectively,could meet the requirements for A5.0 B07 grade of autoclaved aerated concrete block(GB11968-2020)as the addition amount of construction waste ranged from 50wt%to 60wt%.The properties of AAC prepared with compounding WC and CB were improved,as the mass ratio of WC to CB(m(WC)∶m(CB))decreased,the compressive strength of the AAC samples persistently increased,while the dry bulk density firstly decreased and then increased.When the m(WC)∶m(CB)was in the range of 2∶3—3∶2,the compressive strength and dry bulk density of the samples could meet the requirements for A5.0 B06 grade of autoclaved aerated concrete block(GB11968-2020).During the autoclave curing process,the SiO_(2),Al_(2)O_(3),Ca(OH)2,feldspar,calcium-rich calcium silicate hydrate(α-C_(2)SH)in the green body interreacted to generate a large amount of flaky tobermorite,semicrystalline CSH(I),CSH gel,and a small amount of hydrogarnet,anhydrite,together with residue quartz and calcite of raw materials,filled with the gaps in the hole wall and staggered together to form a certain porous and framework hierarchy,improved the strength and reduced the density of AAC.The samples prepared with compounding WC and CB contained more well-crystallized tobermorite,CSH(I),and moderate CSH gel to form dense network structure,favored the better properties of AAC.

关 键 词：废弃混凝土 废弃黏土砖 蒸压加气混凝土 抗压强度 干体积密度 水化产物 

分 类 号：TU528.2[建筑科学—建筑技术科学]