(1 山西工程科技职业大学发展规划部, 晋中 030619; 2 山西六建集团有限公司, 太原 030024;3 呼和浩特职业学院建筑工程学院, 呼和浩特 010020; 4 内蒙古农业大学水利与土木建筑工程学院, 呼和浩特 010018)

摘要: 为研究珊瑚砂掺量对超高性能混凝土(UHPC)的抗压、抗折力学性能及干湿循环耐久性的影响,用珊瑚砂取代石英砂制备成 UHPC,替代率分别为 0%、20%、40%、60%、80%、100%,研究了不同珊瑚砂掺量的 UHPC 的抗压、抗折和抗硫酸盐干湿循环能力. 结果表明:在标准养护 28d 后,掺入 100% 的珊瑚砂 UHPC 的抗压强度为108. 9MPa,抗折强度为 37. 7MPa,珊瑚砂由于其吸水性强的特点会抑制 UHPC 早期抗压强度(28d 前)的发展,抗折强度变化率高于抗压强度;随着硫酸钠干湿循环次数的增加,UHPC 抗压强度逐渐增加,珊瑚砂掺量与抗压强度差值之间存在较好的相关性;干湿循环 15 次时,UHPC 基体中水泥砂浆结构更加疏松多孔,孔隙直径较大,水化产物晶体数量少,而干湿循环 60 次时,珊瑚砂掺量为 100%的 UHPC 组的扫描电镜中钙矾石晶体发育状态良好,其结构尺寸较小且极为纤细.

关键词: 珊瑚砂; 超高性能混凝土; 抗压强度; 抗折强度; 干湿循环; 耐久性

中图分类号:TU528 文献标志码:A 文章编号:1002-848X(2023)10-0082-04

DOI:10. 19701 / j. jzjg. 20211563

Study on influence of coral sand content on mechanics and dry-wet cycle durability of ultra-high performance concrete

WEN Yuanyuan1, GONG Yongsheng2, REN Rong3, YAN Jianwen4

(1 Development Planning Department of Shanxi Vocational University of Engineering and Technology, Jinzhong 030619,China; 2 Shanxi Sixth Construction Co. , Ltd. , Taiyuan 030024, China; 3 Architecture and Engineering College,Hohhot Vocational College, Hohhot 010020, China; 4 Water Conservancy and Civil Engineering College, InnerMongolia Agricultural University, Hohhot 010080, China)

Abstract: In order to study the influences of compressive, flexural mechanical properties and dry-wet cycle durability ofcoral sand content to ultra-high performance concrete (UHPC), coral sand was used to replace quartz sand to prepareUHPC, and the substitution rate was 0%, 20%, 40%, 60%, 80% and 100% respectively to study the compressive,flexural and sulfate dry-wet cycle resistance of UHPC with different coral sand contents. The results show that after 28 daysof standard curing, the compressive strength of UHPC mixed with 100% coral sand is 108. 9 MPa, and the flexural strengthis 37. 7 MPa. Because of its strong water absorption, coral sand can inhibit the development of early compressive strength ofUHPC (before 28d), and the change rate of flexural strength is higher than that of compressive strength. The compressivestrength of UHPC increased gradually with the increase of dry-wet cycles of sodium sulfate, and there is a good correlationbetween the content of coral sand and the difference of compressive strength. When the dry-wet cycles are 15 times, thestructure of cement mortar in the UHPC matrix is more loose and porous, the pore diameter is larger, and the number ofhydration product crystals is less. However, when the dry-wet cycles are 60 times, the crystal of ettringite in the UHPCgroup with 100% coral sand content is in a good state, and its structure size is small and extremely slim.

Keywords:coral sand; ultra-high performance concrete (UHPC); compressive strength; flexural strength; wet-dry cycle;durability

∗山西省教育厅职业院校教师素质提高计划国家级培训项目(ZDF03-FC190901_2).

第一作者:温媛媛,硕士,副教授,主要从事建筑技术科学、建筑结构方面研究,Email:daynight9999@ outlook. com.

[引用本文] 温媛媛,弓永胜,任蓉,等. 珊瑚砂掺量对超高性能混凝土力学及干湿循环耐久性的影响研究[J]. 建筑结构,2023,53(8):82-85,81. WEN Yuanyuan,GONG Yongsheng,REN Rong,et al. Study on influence of coral sand content onmechanics and dry-wet cycle durability of ultra-high performance concrete[J]. Building Structure,2023,53(8):82-85,81.