浆体流变特性对大掺量粉煤灰混凝土早龄期拉伸徐变的影响  

Influence of the rheological properties of paste on the early-age tensile creep of high-volume fly ash concrete

作　　者：倪彤元[1,2] 姚水丰 陈卫忠 杨杨 刘金涛[1,2] 聂海波 NI Tongyuan;YAO Shuifeng;CHEN Weizhong;YANG Yang;LIU Jintao;NIE Haibo(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310023,China;Zhejiang Key Laboratory of Civil Engineering Structures&Disaster Prevention and Mitigation Technology,Hangzhou 310023,China;Hangzhou Yuhang Hengli Concrete Co.,Ltd.,Hangzhou 310014,China;Zhejiang Tianzao Environmental Protection Technology Co.,Ltd.,Lishui 323000,China)

机构地区：[1]浙江工业大学土木工程学院,杭州310023 [2]浙江省工程结构与防灾减灾技术重点实验室,杭州310023 [3]杭州余杭恒力混凝土有限公司,杭州310014 [4]浙江天造环保科技有限公司,丽水323000

出　　处：《复合材料学报》2024年第11期6111-6121,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金面上项目(51778583,52379136);浙江省重点研发计划项目(2021C01060)。

摘　　要：混凝土中浆体的流变特性是影响其拉伸徐变的重要因素之一。通过纳米压痕技术分析大掺量粉煤灰水泥基浆体(掺量为60wt%)微观力学性能、微观徐变等流变特性;同时实验研究相同水泥基浆体的大掺量粉煤灰混凝土(HVFAC)拉伸徐变时变规律,提出考虑浆体流变特性的HVFAC拉伸徐变ZC模型预测表达式。结果表明:水泥基浆体在相同测试龄期时,粉煤灰对其微观徐变的发展有促进作用;而等质量粉煤灰替代时,微观徐变随着测试龄期的后延更快趋于收敛;粉煤灰、加载龄期对徐变发展的影响与其不含骨料水泥基浆体的微观徐变影响规律具有一致性。在0 d~28 d龄期内某一龄期时的混凝土弹模与ZC模型中的Maxwell体、Kelvin弹簧组合体最终比徐变的乘积(E_(t,28 d)/(E_(V)+E_(H))、E_(t,28 d)/χφ)、混凝土黏性系数(φ)与相对抗压强度(fc(t0)/fc,28 d)、浆体微观徐变模量(C)、特征时间(τ)与测试龄期相关性分析表明这些参数与函数y=axb有较好的吻合度。水泥基浆体流变特性参数与ZC拉伸徐变模型参数相结合建立考虑水泥浆体流变特性的HVFAC拉伸徐变发展的预测表达式能反映模型单元体结构。It is one of important factors affecting on concrete tensile creep that the rheological properties of concrete paste.The microscopic mechanical properties and rheological characteristics of cementitious paste containing high volume fly ash(60wt%)were analyzed by nanoindentation.And the same time,the tensile creep law dependent on ages of high-volume fly ash concrete containing same cementitious paste was experimental studied.The predictive function expressions of the high volume fly ash concrete(HVFAC)tensile creep considering the rheological properties of paste were proposed.The nanoindentation results show that the fly ash promotes the paste's micro creep development of paste at the same test ages,and the micro creep of paste tends to converge quickly with the delay of test age which the cement is replaced with the same quality fly ash.The influence of fly ash and loading age on the development of HVFAC creep is consistent with the influence law of cementitious paste's micro creep without aggregate.Base on the correlation analysis on the parameters of the products of concrete elastic modulus at some age(0 d-28 d)and the final specific creep of Maxwell body and Kelvin spring body in the ZC model respectively(E_(t,28 d)/(E_(V)+E_(H)),E_(t,28 d)/χφ),the viscosity coefficient of concrete(φ)and relative compressive strength(fc(t0)/fc,28 d),the parameters of the microscopic creep modulus of paste(C),characteristic time(τ)and test ages,it shows that these parameters are in good agreement with the function y=axb.The tensile creep prediction expression of ZC model considering the rheological properties of cement paste can reflect the structure of the model unit cell.

关 键 词：纳米压痕 拉伸徐变 浆体流变特性 粉煤灰 ZC模型 

分 类 号：TB332[一般工业技术—材料科学与工程]