空心玻璃微珠对轻质超高性能混凝土强度和自收缩性能的影响  

Effects of hollow glass microspheres on strength and autogenous shrinkage of lightweight ultra-high performance concrete

作　　者：潘会滨 潘慧敏[2] 闫帅君 PAN Huibin;PAN Huimin;YAN Shuaijun(Shanxi Province Communications Planning Survey and Designing Institute Co.,Ltd.,Taiyuan 030032,China;Key Laboratory of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province,Yanshan University,Qinhuangdao 066004,China)

机构地区：[1]山西省交通规划勘察设计院有限公司,山西太原030032 [2]燕山大学河北省土木工程绿色建造与智能运维重点实验室,河北秦皇岛066004

出　　处：《混凝土》2023年第3期92-96,共5页Concrete

基　　金：国家自然科学基金“早期扰动对混凝土性能的影响及其微细观损伤机理”(51608469)。

摘　　要：采用密度极低的空心玻璃微珠(Hollow glass microspheres,HGM)搭配陶砂作为减重材料,制备了轻质超高性能混凝土(Lightweight ultra high performance concrete,LUHPC),研究了HGM对混凝土物理力学性能和早期自收缩性能的影响,分析了影响机理。结果表明,掺入HGM使净浆体系的表观密度减小,其作为填充材料有助于实现水泥基材料的轻质化。HGM的加入使LUHPC的表观密度和强度均降低,其掺量达到8%后,表观密度降至2 000 kg/m^(3),抗压、抗折强度较基准组分别降低约12%和10%。正球体的HGM表面光滑,可以发挥“滚珠”效应,显著提高了LUHPC的工作性。各组LUHPC的抗压、抗折强度均分别超过了100、15 MPa,满足高强度的要求,HGM对比强度的影响则存在较优值。加入HGM未改变混凝土的自收缩过程,但5%HGM使混凝土在72 h的收缩率较基准组增大153×10^(-6)。SEM测试表明,HGM与水泥基体连接紧密,呈均匀嵌入式分布,佐证了宏观测试结果。In this study,lightweight ultra high performance concrete(LUHPC)was prepared by using hollow glass microspheres(HGM)with very low specific gravity and ceramic sand as weight reducing materials.The influence of HGM on the physical and mechanical properties and early autogenous shrinkage of concrete was studied,and the influence mechanism was analyzed.The results show that the apparent density of the paste system decreases with the addition of HGM,and using HGM as the filling material is helpful to realize the lightweight of cement-based materials.The addition of HGM reduces the apparent density and strength of LUHPC.When the HGM content reaches 8%,the apparent density decreases to 2000 kg/m3,and the compressive strength and bending strength decreases about 12%and 10%,respectively,compared with the reference group.The HGM surface of the positive sphere is smooth,which can play a“ball”effect and significantly improve the workability of LUHPC.The compressive strength and flexural strength of LUHPC in each group exceed 100 MPa and 15 MPa respectively,meeting the requirements of high strength.The effect of HGM contrast intensity has a better value.Adding HGM did not change the self-shrinkage process of concrete,but 5%HGM increased the shrinkage rate of concrete by 153×10-6 compared with the reference group at 72 h.SEM test shows that HGM is closely connected with cement matrix and uniformly embedded,which supports the macroscopic test results.

关 键 词：超高性能混凝土 轻质 空心玻璃微珠 强度 早期自收缩 

分 类 号：TU528.041[建筑科学—建筑技术科学]