不同强度等级自密实混凝土鲁棒性研究  

Study on the Robustness of Self-compacting Concrete with Different Strength Grades

作　　者：关素敏 蔡祥磊 蓝堂伟 李颉 

机构地区：[1]四川华西绿舍建材有限公司,四川成都610041

出　　处：《混凝土世界》2023年第9期56-60,共5页China Concrete

摘　　要：自密实混凝土有着良好的流动性,便于施工,但原材料的变化使其工作性能具有一定的敏感性。为探究自密实混凝土对原材料的敏感性,对C30、C50强度等级的自密实混凝土进行配合比调整,主要包括外加剂掺量、用水量、胶凝材料用量及砂率,通过试验判断自密实混凝土的工作性能、力学性能及早期抗裂性能对不同参数波动的敏感性(即鲁棒性),并通过一种鲁棒性评价方法对其进行评价。结果表明:对于工作性能,用水量和砂率是主要影响因素,同时随着强度等级的增加,混凝土对外加剂用量越敏感;对于力学性能,胶凝材料用量是鲁棒性指数最高的,胶凝材料用量增加20 kg/m^(3)时,C30、C50自密实混凝土强度提高最大,分别提高10%、8.1%;对于早期抗裂性能,C30自密实混凝土对这4种因素的敏感性相差不大,C50自密实混凝土对胶凝材料用量的敏感性最弱,对砂率的敏感性最强,当砂率降低2%时,裂缝总面积提高39.4%。Self-compacting concrete has good fluidity and is convenient for construction,but the working performance of self-compacting concrete is sensitive to changes in raw materials.In order to explore the sensitivity of self-compacting concrete to raw materials,by adjusting the mix ratio of self-compacting concrete with two strength grades of C30 and C50,mainly including the fluctuation of admixture content,water consumption,cementing material and sand rate,the sensitivity of self-compacting concrete's working performance,mechanical properties and early cracking resistance to different parameter fluctuations(i.e.,robustness)was determined by tests.And a robustness evaluation method is used to evaluate it.The results show that the water consumption and sand rate are the main factors affecting the working performance,and the concrete is more sensitive to the amount of admixture with the increase of strength grade.For mechanical properties,the strength of C30 and C50 self-compacting concrete increases the most when the dosage of cementing material is increased by 20 kg/m^(3),which increased by 10%and 8.1%,respectively.For early crack resistance,C30 self-compacting concrete has little difference in sensitivity to these four factors,and C50 self-compacting concrete has the weakest sensitivity to the amount of cementing material and the strongest sensitivity to the sand rate.When the sand rate is reduced by 2%,the total crack area is increased by 39.4%.

关 键 词：自密实混凝土 鲁棒性 工作性能 力学性能 早期抗裂性能 

分 类 号：TU528[建筑科学—建筑技术科学]