图像分析宏观孔孔隙率对混凝土抗压强度的影响  

Analysis of the Influence of Porosity of Macroscopic Pore on Concrete Strength by Image Method

作　　者：朱洪波[1] 闫美珠[1] 李晨[1] 成轶杰 吴凯凡 

机构地区：[1]同济大学先进土木工程材料教育部重点实验室,上海201804

出　　处：《建筑材料学报》2015年第2期275-280,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51302189)

摘　　要：采用不同种类的气孔调节材料配制出15种不同含气量(体积分数)的混凝土.研究了混凝土3,7,28d抗压强度与含气量之间的关系;采用图像法研究了不同含气量混凝土中孔径大于200×103 nm的宏观孔孔隙率(体积分数);对比分析了混凝土宏观孔孔隙率和含气量对混凝土28d抗压强度的影响规律.结果表明:混凝土28d抗压强度与含气量的线性关系较强,而混凝土3d和7d抗压强度与含气量的线性关系较弱;混凝土28d抗压强度对宏观孔孔隙率变化的敏感性显著高于其对含气量变化的敏感性,即混凝土中宏观孔孔隙率变化对其28d抗压强度影响更大;调整气孔调节材料的品种,可使混凝土含气量从1.5%提高到9.0%,而宏观孔孔隙率只从0.81%增加到1.48%,其所占含气量的比例从超过55%降低到16%左右,即可在有效调节混凝土含气量的同时,控制其宏观孔的数量.Fifteen kinds of concrete with different air contents（by volume） were prepared by adjusting the air product（AP）. The relationships between the 3,7,28 d compressive strengths of concrete and air con- tents were investigated. An image analysis method was used to study the porosity（by volume） of macro- scopic pore（diameter〉200 × 10^3 nm） of concrete with different air contents, and the effects of porosity of macroscopic pore and air content on 28 d compressive strength of concrete were studied. The results show that 28 d compressive strength of concrete has a stronger linear relationship with air content, and 3,7 d compressive strengths of concrete have a weaker linear relationship with air content. The sensibility of 28 d compressive strength on the change of porosity of macroscopic pore is larger than that on the change of air content, which means that the porosity of macroscopic pore of concrete effects 28 d compressive strength more significantly. By adjusting the air product the air content can be increased from 1.5% to 9.0% with porosity of macroscopic pore only increasing from 0. 81% to 1.48%, and the ratio of porosity of macro- scopic pore to air content can be decreased from more than 55% to 16% or so. It indicates that the air con- tent of concrete can be controlled effectively, and the amount of macroscopic pore can be limited at the same time.

关 键 词：混凝土 含气量 宏观孔孔隙率 抗压强度 图像法 

分 类 号：TU528.0[建筑科学—建筑技术科学]