摘要
重晶石骨料的高度结晶结构使其具有易碎性,导致重晶石防辐射混凝土的力学性能差,限制其在高压高热核工程等辐射严重的建筑中应用。为研究聚丙烯纤维掺入对重晶石混凝土力学性能的影响,通过试验分析聚丙烯纤维掺量(0、3、6、9 kg/m3)对不同强度等级重晶石混凝土力学性能的影响,同时量化重晶石混凝土立方体抗压强度的尺寸效应,此外,采用扫描电子显微镜(SEM)探究聚丙烯纤维重晶石混凝土的细观结构。结果表明:纤维表面被致密硬化的水泥基质包裹,提高了聚丙烯纤维-水泥基体的结构强度,从而使得重晶石混凝土的劈裂抗拉强度和抗折强度提高;随着纤维掺量的增加,试件28 d抗压强度提高了4.3%~19.6%,28 d抗折和劈裂抗拉强度分别提高了1.8%~25.0%和4.9%~27.7%;当纤维掺量较大时,水泥含量无法满足纤维的包裹,因此重晶石混凝土抗压强度随着纤维掺量的增加呈现先增大后降低的趋势;重晶石混凝土立方体抗压强度的尺寸效应随着纤维掺量的增加逐渐显著,与未掺纤维的试件相比,尺寸效应系数η100增大0.2%~5.9%、尺寸效应系数η200增大1.8%~5.9%。
The highly crystalline structure of barite aggregate makes it fragile,resulting in poor mechanical properties of barite radiation-proof concrete,which limits its application in buildings with severe radiation such as high-pressure and high-thermonuclear projects.To study the effect of polypropylene fiber incorpora-tion on the mechanical properties of barite concrete,the effects of polypropylene fiber content(0,3,6,9 kg/m3)on the mechanical properties of barite concrete with different strength grades were analyzed,and the size effect of barite concrete cube compressive strength was quantified.The meso-structure of polypropylene fiber barite concrete was studied via SEM test.The results showed that the surface of PR40 fiber was wrapped by a dense hardened cement matrix,which improved the structural strength of the polypropylene fiber-cement matrix,thus improving the splitting tensile strength and flexural strength of barite concrete.With the increase in fiber content,the 28 d compressive strength of the specimens increased by 4.3%-19.6%,and the 28 d flexural and splitting tensile strength increased by 1.8%-25.0%and 4.9%-27.7%,respectively.When the fiber content increased,the cement content could not meet the fiber wrapping,so the compressive strength of barite concrete increased first and then decreased with the increase of fiber contents.The size effect of the compressive strength of barite concrete cubes was gradually significant with the increase of fiber content.Compared with the specimens without fiber,the size effect coefficientη100 increased by 0.2%-5.9%,and the size effect coefficientη200 increased by 1.8%-5.9%.
作者
王庆贺
徐苏宁
王禹澄
王东
王萌
宋晓光
WANG Qinghe;XU Suning;WANG Yucheng;WANG Dong;WANG Meng;SONG Xiaoguang(School of Civil Engineering,Shenyang Jianzhu University,Shenyang 110168,China;China Construction Fangyuan East China City Development and Construction Co.,Ltd.,Suzhou 215000,China)
出处
《工业建筑》
2024年第7期210-216,共7页
Industrial Construction
基金
国家自然科学基金项目(51808351)
辽宁省科技厅应用基础研究计划项目(2022JH5/101300524)
辽宁省教育厅项目(JYTMS20231562)
住房和城乡建设部科学技术计划项目(2019-K-054)。
