摘要
为研究冻融循环下掺合料对超高性能混凝土(UHPC)强度的影响,以硅粉(10%、15%、20%)、偏高岭土(5%、10%、15%)、镀铜钢纤维(0.5%、1.0%、1.5%、2.0%)为掺合料,开展冻融前后UHPC抗压和抗折强度试验.建立岭回归模型分析UHPC冻融前后强度变化,并对影响UHPC冻融后强度变化的关键因素进行分析.结果表明:UHPC的强度随硅粉、偏高岭土掺量的增加先增加后减小,随镀铜钢纤维掺量的增加而增大;冻融循环500 次后UHPC的抗压和抗折强度均有所下降,抗压强度下降11%～15%,抗折强度下降13%～16%;三种掺料对UHPC强度的影响大小为:镀铜钢纤维＞偏高岭土＞硅粉.硅粉、偏高岭土、镀铜钢纤维对UHPC强度影响明显.
Abstract
In order to investigate the effects of admixtures on the strength of UHPC under freezing-thawing cycles,compressive and flexural strength tests were carried out with silica fume(10%,15%,20%),metakaolin(5%,10%,15%),and copper-plated steel fiber(0.5%,1.0%,1.5%,2.0%)as the admixtures.A ridge regression model was established to analyze the strength changes of UHPC before and after freezing-thawing.At the same time,the key factors affecting the strength changes of UHPC after freezing-thawing were analyzed.The results are as follows.Silica fume,metakaolin,copper-plated steel fibre had obvious influence on the strength of UHPC.The strength of UH-PC increased and then decreased with the increase of silica fume and metakaolin content.It increased with the increase of copper-plated steel fiber content.The compressive and flexural strength of UHPC decreased after 500 times of freeze-thawing cycles,with the compressive strength decreasing by 11%～15%and the flexural strength decreasing by 13%～16%.The effects of the three admixtures on the strength of UHPC from high to low were copper-plated steel fibre,metakaolin,silica fume.The error of the fitting results of the ridge regression analysis was small,and the accuracy of the model was high.
基金项目
国家自然基金面上项目(52179079)
陕西省自然科学基础研究计划(2023-JC-QN-0519)
陕西省博士后科研项目(2023BSHYDZZ65)
西北农林科技大学大学生科创基金(S202010712181)
维普
万方数据