| 摘要: |
| 以水泥、粉煤灰和硅灰为原材料，利用修正的Andreasen-Andersen（MAA）模型指导超高性能混凝土（UHPC）配合比设计，研究了配合比、水胶比和养护方式对UHPC工作性能、抗压强度、表观密度和水化产物特性的影响，以残差平方和（RSS）作为堆积密实度指标，分析了UHPC抗压强度和水化产物特性.结果表明：硅灰对提升UHPC的堆积密实度有利；当UHPC的残差平方和达到最小值570.64时，标准养护28 d和蒸气养护3 d条件下的UHPC抗压强度分别可达到最大值140.4、153.9 MPa，说明基于MAA模型设计的UHPC配合比合理；通过研究UHPC水化产物特性，发现UHPC中水泥水化反应不完全，高水胶比和高水泥掺量可促进水化反应，粉煤灰与硅灰在碱性环境中反应会消耗氢氧化钙，形成水化硅酸钙（C-S-H）凝胶，降低了体系的钙硅摩尔比，改善了UHPC的显微结构，提升了UHPC的致密性与强度. |
| 关键词: 超高性能混凝土 最紧密堆积 MAA模型 微观分析 抗压强度 |
| DOI：10.3969/j.issn.1007-9629.2022.07.006 |
| 分类号:TU528 |
| 基金项目:甘肃省科技重大专项计划（21ZD3GA002）；甘肃省科技厅重点研发计划（18YF1GA036）；甘肃省交通运输厅2021年第一批揭榜挂帅制项目 |
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| Research on Mix Design and Characteristics of UHPC Matrix Mixture Based on MAA Model |
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WEN Decheng1,2, WEI Dingbang1,2, WU Laidi1, REN Guobin1, GUO Haizhen1
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1.Gansu Province Transportation Planning， Survey and Design Institute Co.， Ltd.， Lanzhou 730030， China;2.School of Materials and Technology， China University of Geosciences （Beijing）， Beijing 100083， China
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| Abstract: |
| Cement， fly ash and silica fume were used as raw materials， and modified Andreasen-Andersen（MAA） model was used to guide the mix design of the ultra-high performance concrete （UHPC）. The work performance， compressive strength， apparent density and hydration product characteristics of UHPC under different mix proportions， water-binder ratios and curing methods were studied. The residual sum of squares （RSS） was used as an index of the stacking density， and the characteristics of hydration products and compressive strength of UHPC was analyzed to prove the rationality of MAA model guiding UHPC mix design. The results show that silica fume was beneficial to improve the stacking density of UHPC. When the RSS of UHPC reaches the minimum of 570.64， the compressive strength of UHPC under standard curing and steam curing reaches the maximum of 140.4， 153.9 MPa， indicating that the mix proportion design of UHPC by MAA model has high accuracy. Through the research of UHPC hydration products， it is found that the hydration reaction is not complete. High water-binder ratio and high cement content can promote the hydration reaction. The reaction of fly ash and silica fume in an alkaline environment consumes calcium hydroxide to form calcium silicate hydrate （C-S-H） gel. The system Ca/Si mole ratio is reduced， the microstructure of UHPC is improved， and the density and strength of UHPC are improved. |
| Key words: ultra-high performance concrete（UHPC） most close packing modified Andreasen-Andersen（MAA） model microscopic analysis compressive strength |
