矿物掺合料混凝土抗碳化性能及预测模型  

Carbonation resistance and prediction model of mineral admixture concrete

作　　者：司秀勇 户伟华 潘慧敏[2] SI Xiuyong;HU Weihua;PAN Huimin(Tianjin Transportation Technical College,Tianjin 300380,China;College of Civil Engineering and Mechanics,Yanshan University,Qinhuangdao 066004,China)

机构地区：[1]天津交通职业学院,天津300380 [2]燕山大学建筑工程与力学学院,河北秦皇岛066004

出　　处：《混凝土》2024年第1期17-20,27,共5页Concrete

基　　金：国家自然科学基金(51608469)。

摘　　要：通过快速碳化试验,结合SEM微观形貌观测和EDS化学组成分析,研究粉煤灰和矿渣对混凝土抗碳化性能的影响,探讨了影响机理,并基于指数函数建立了矿物掺合料混凝土碳化深度预测模型。研究结果表明:掺入矿物掺合料使混凝土强度和抗碳化性能均有所降低。在总掺量一致的条件下,单掺粉煤灰较复掺粉煤灰和矿渣对混凝土性能的影响更大。当粉煤灰掺量超过40%后,混凝土碳化深度增长速度极快,单掺60%粉煤灰的56 d碳化深度已达到18.5 mm,而复掺粉煤灰和矿渣总量60%组56 d碳化深度仅为6.5 mm。SEM-EDS分析结果表明,矿物掺合料掺量较小时,净浆试样微观结构比较致密,掺量超过40%后,混凝土微观结构松散,孔隙和缺陷增多,佐证了混凝土力学性能和抗碳化性能试验结果。建立的矿物掺合料混凝土碳化深度模型曲线与试验结果吻合较好,拟合相关系数均在0.89以上。Through rapid carbonation test,combined with SEM microscopic morphology observation and EDS chemical composition analysis,the influence of fly ash and slag on the carbonation resistance of concrete was analyzed.The influence mechanism of mineral admixtures on concrete was discussed.Based on the exponential function,the prediction model of carbonation depth of mineral admix-ture concrete was established.The results show that the strength and carbonation resistance of concrete are reduced by adding mineral ad-mixtures.Under the condition that the total content is the same,the influence of single fly ash on concrete performance is greater than that of mixed fly ash and slag.When the content of fly ash exceeds 40%,the carbonation depth of concrete increases rapidly.The carbon-ation depth of the 60%fly ash group alone at 56 days has reached 18.5 mm,while the carbonation depth of the 60%fly ash and slag group at 56 days is only 6.5 mm.The results of SEM-EDS analysis show that the microstructure of the paste sample is relatively dense when the mineral admixture content is small.When the content of mineral admixtures exceeds 4o%,the microstructure of concrete is loose,and pores and defects increase.SEM-EDS analysis corroborates the test results of concrete mechanical properties and carbonation resistance.The carbonation depth model curve of mineral admixture concrete established is in good agreement with the test results,and the fitting correlation coefficient is above 0.89.

关 键 词：混凝土 矿物掺合料 抗碳化 预测模型 微观结构 

分 类 号：TU528.01[建筑科学—建筑技术科学]