组成及骨料特性对UHPC基体流动性和抗压强度的影响  

Effects of Composition and Aggregate Characteristics on the Flowability and Compressive Strength of UHPC Matrix

作　　者：周敏 吴泽媚 欧阳雪 胡翔 史才军 ZHOU Min;WU Zemei;OUYANG Xue;HU Xiang;SHI Caijun(Key Laboratory for Green&Advanced Civil Engineering Materials and Application Technologies of Hunan Province,College of Civil Engineering,Hunan University,Changsha 410082,China;International Science and Technology Innovation Center for Green&Advanced Civil Engineering Materials of Hunan Province,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,绿色先进土木工程材料及应用技术湖南省重点实验室,长沙410082 [2]湖南省绿色先进土木工程材料国际科技创新合作基地,长沙410082

出　　处：《材料导报》2023年第18期97-105,共9页Materials Reports

基　　金：国家自然科学基金(52008164);中央高校基本科研专项资金(531118010484);国家重点研发计划(2018YFC0705400);湖南省自然科学基金(2022JJ30144)。

摘　　要：本工作通过调整砂胶比和拟合改进的Andreasen-Andersen颗粒堆积模型,计算得到了UHPC基体中各固体组分的比例。基于新拌超高性能混凝土(UHPC)基体的湿堆积密度和流动性确定了高效减水剂的最优掺量。研究分析了不同配合比设计参数(砂胶比和胶凝材料组分)、骨料特性(颗粒球形度和圆度)对UHPC基体的流动性和抗压强度的影响。结果表明:当砂胶比从0.8增加为1.2时,掺河砂的UHPC基体的湿堆积密度、流动性和7 d抗压强度逐渐降低;对比调整砂胶比和改变胶凝材料组分的掺量,UHPC基体的流动性和湿堆积密度变化趋势主要受砂胶比影响;当高效减水剂掺量为0.5%~2.0%时,UHPC基体的PFT、湿堆积密度和流动性先缓慢升高后迅速下降;骨料形状对UHPC基体的湿堆积密度、流动性和28 d抗压强度的影响较大;在UHPC基体实现紧密堆积后,影响UHPC基体的抗压强度的主要因素为骨料形貌,而胶凝材料组分掺量的影响较小;当骨料最大粒径相同时,增加骨料的球形度和圆度显著增加了UHPC基体的流动性,但降低了UHPC基体的抗压强度。This paper calculates the proportion of each solid component in the UHPC matrix by adjusting the sand binder ratio and fitting the modified Andreasen and Andersen particle packing model.The optimal superplasticizer dosage in UHPC matrix is determined based on the wet packing density and flowability of fresh mixture.The effects of mixture design parameters(sand binder ratio,cementitious material composition),aggregate characteristics(particle sphericity,and roundness)on the flowability and compressive strength of UHPC matrix are analyzed.Test results show that when the sand binder ratio increases from 0.8 to 1.2,the wet packing density,flowability,and 7 d compressive strength of the UHPC matrix gradually decrease.After the content of cementitious materials is changed by adjusting the sand binder ratio,the flowability and wet packing density of UHPC matrix are mainly affected by the sand binder ratio.When the superplasticizer content was 0.5%—2.0%,the paste film thickness,wet packing density and flowability of UHPC matrix increased slowly and then decreased rapidly.The aggregate shape is the main factor affecting the wet packing density,flowability,and 28 d compressive strength of UHPC matrix.The main factor affecting the compressive strength of UHPC matrix is the aggregate characteristics after the UHPC matrix achieves close packing,while the cementitious material content has little effect.When the maximum particle size of aggregate is the same,the increased sphericity and roundness of crushed aggregate significantly increase the UHPC matrix's flowability while reducing the compressive strength.

关 键 词：超高性能混凝土基体 颗粒紧密堆积理论 配合比设计参数 骨料特性 流动性 抗压强度 

分 类 号：TU528[建筑科学—建筑技术科学]