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中高强混凝土抗压强度与气孔分布特征关系模型研究

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为探究气孔分布特征与中高强混凝土抗压强度之间的定量关系,采用低场核磁共振成像分析系统与全自动压力试验机开展了不同气孔分布特征下的高强混凝土抗压强度试验.通过对Ryshkewitch半经验公式模型进行验证和改进,建立了中高强混凝土抗压强度与孔结构关系模型.结果表明:混凝土孔隙率会随着砂率和初始含气量的增加而逐渐增加,相比于提高砂率,提高初始含气量更容易得到差异性较大的孔隙率;提高砂率使非毛细孔占比增加了17.2％,毛细孔占比降低了13.0％;提高初始含气量使毛细孔占比增加了 12.7％,凝胶孔占比降低了 12.6％.基于Ryshkewitch半经验公式改进的模型R2接近于1,P值＜0.05,可以更准确地描述孔隙分布特征与抗压强度的定量关系.
Modeling the Relationship between Compressive Strength and Pore Distribution Characteristics of Medium-to-High Strength Concrete
To investigate the quantitative relationship between pore distribution characteristics and the compressive strength of medium-to-high strength concrete,we conducted comprehensive compressive strength tests by using a low-field nuclear magnetic resonance(NMR)imaging analysis system in conjunction with a fully automatic pressure testing machine.By validating and modifying the Ryshkewitch semi-empirical equation model,we established the quantitative relationship model between pore distribution characteristics and compressive strength.Test results dem-onstrate several key findings.First,an increase in sand rate and initial entrapped air content of concrete leads to a gradual increase in porosity.Increasing the initial air content proves to be more effective in generating a more varia-ble porosity compared to increasing the sand rate.Specifically,by increasing the sand rate,the percentage of non-capillary pores increases by 17.2％while the percentage of capillary pores decreases by 13.0％.On the other hand,increasing the initial air content results in a 12.7％increase in capillary pores and a 12.6％decrease in gel pores.By employing the model based on modified Ryshkewitch semi-empirical equation,we achieved accurate results with an R2 value close to 1 and a P-value less than 0.05,effectively describing the quantitative relationship between pore distribution characteristics and compressive strength.

medium-to-high strength concretecompressive strengthpore distributionlow frequency NMRsand rateinitial air contentporosityRyshkewitch semi-empirical equation

杨帅、毛海涛、刘畅、王晓菊

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山西农业大学城乡建设学院,山西晋中 030600

新疆农业大学水利与土木工程学院,乌鲁木齐 830000

中高强混凝土 抗压强度 气孔分布 低频核磁共振 砂率 初始含气量 孔隙率 Ryshkewitch半经验公式

国家自然科学基金青年基金山西省自然科学基金面上项目山西省自然科学基金面上项目山西农业大学211省改革高层次人才引进项目

422071022021030212241512021030212231322021XG009

2024

10.11988/ckyyb.20221442

长江科学院院报
长江科学院

长江科学院院报

CSTPCD北大核心
影响因子：0.618
ISSN：1001-5485
年,卷(期)：2024.41(4)
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