附加用水量对再生砂混凝土工作性和力学性能的影响  

Effect of Additional Water Amount on the Workability and Mechanical Properties of Concrete with Recycled Fine Aggregates

作　　者：李北星[1] 陈鹏博 殷实 易浩[1] LI Beixing;CHEN Pengbo;YIN Shi;YI Hao(State Key Laboratory of Silicate Materials for Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070

出　　处：《材料导报》2024年第1期98-104,共7页Materials Reports

基　　金：国家重点研发计划课题(2020YFC1909904)。

摘　　要：再生砂掺量和附加用水量对新拌和硬化再生砂混凝土的性能有重要影响。本工作制备了再生砂掺量(γRFA)为30%、50%、70%、100%(质量分数,下同),附加用水量补偿系数(kwa)为0.6、0.75、0.9、1.0的16组再生砂混凝土,测试了这些再生砂混凝土的工作性(坍落度、扩展度与扩展时间)与力学性能(抗压、劈拉强度与弹性模量),分析了kwa和γRFA对再生砂混凝土性能的影响规律,获得了kwa的合理取值范围。结果表明,随着kwa的降低,再生砂混凝土的工作性下降,力学性能增大;γRFA对混凝土力学性能的影响与附加用水量有关,在中低附加用水量(kwa=0.6、0.75)条件下,随着γRFA的增加,再生砂混凝土的部分力学性能指标增大且其值高于天然砂混凝土,而在高附加用水量(kwa=0.9、1.0)下,再生砂混凝土的力学性能随着γRFA的增加呈线性降低。γRFA低于50%对再生砂混凝土力学性能的影响较小,kwa值在0.75~0.9范围变化对再生砂混凝土工作性能与力学性能的影响均相对较小。The replacement ratio of recycled fine aggregate(RFA)and amount of additional water have significant impact on the performance of both fresh and hardened recycled concrete.16 groups of concrete specimens were prepared with different RFA replacement ratios(γRFA)of 30%,50%,70%,and 100%and compensation factors of additional water consumption(k wa)of 0.6,0.75,0.9,and 1.0,and the workability(slump,slump flow and flow time)and mechanical properties(compressive strength,flexural strength and modulus of elasticity)of these RFA concretes were tested.According to the test results,the influence law of the above k wa andγRFA parameters on the properties of the RFA concretes was discussed,and a reasonable k wa values range was obtained.The results show that the workability of RFA concrete decreases and the mechanical properties increase as k wa decreases;the influence ofγRFA on the mechanical properties of the RFA concrete are related to the additional water consumption.Under the conditions of low and medium additional water consumption(k wa=0.6,0.75),some mechanical properties of RFA concrete increase with the increase ofγRFA and their values are higher than those of natural sand concrete.Under the conditions of high additional water consumption(k wa=0.9,1.0),the mechanical properties of RFA concrete decrease linearly with the increase ofγRFA.TheγRFA less than 50%has little effect on the mechanical properties of RFA concrete,and the workability and mechanical properties of RFA concrete are little affected by the variation ofγRFA value ranged from 0.75 to 0.9.

关 键 词：再生混凝土 再生砂 附加用水量 工作性能 力学性能 

分 类 号：TU528.01[建筑科学—建筑技术科学]