不同强度等级的混凝土碳化特性研究_《混凝土与水泥制品》杂志社

摘要：采用加速碳化试验，研究了不同强度等级、不同矿物掺合料的混凝土碳化规律，并采用扫描电镜（SEM）、综合热分析法（TG-DSC）、压汞法（MIP）对浆体中的微观形貌、水化产物和孔结构进行了研究。结果表明，水灰比对混凝土的碳化深度影响较大，14d龄期时0.35水灰比混凝土的碳化深度仅为0.57水灰比混凝土碳化深度的25%；掺加30%粉煤灰混凝土抗碳化能力最小，不掺加矿物掺合料混凝土抗碳化能力最大；碳化后浆体密实度增加，孔径细化，孔隙率分别降低21.8%和40.1%。

Abstract: Effect of strength grade and mineral admixture contents on the carbonation characteristics of concrete were investigated via accelerated carbonation method, the microstructure, hydration products and pore structure of concrete surface was analyzed by SEM、TG-DSC、MIP. The results show that the influence of ratio of water-cement on carbonation depth is higher, during the age of 14d, the carbonation depth of the 0.35 water cement ratio concrete is only 25% of the carbonation depth of the 0.57 water cement ratio concrete. The carbonation resistance of concrete was the minimum when the fly ash contents was 30%, and also the carbonation resistance of concrete without admixture was the maximum; the concrete structure compact increased, a large number of holes is refined after carbonation, and the porosity is decreased by 21.8% and 40.1%.

关键词:

混凝土；加速碳化；微观结构

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（1）水灰比对现代混凝土的碳化深度影响较大，14d龄期时0.35水灰比混凝土的碳化深度仅为0.57水灰比混凝土碳化深度的25%，因此，配制混凝土应尽量采用低水灰比，以保证其抗碳化能力。

（2）同一水胶比下掺加粉煤灰的混凝土抗碳化能力最小，28d龄期时掺加30%矿渣混凝土以及不掺加矿物掺合料混凝土的碳化深度分别为掺加30%粉煤灰混凝土碳化深度的85%和71%。因此，应控制混凝土中粉煤灰掺量低于30%。

（3）不同水灰比混凝土在加速碳化后微结构发生显著变化，0.57水灰比混凝土的孔隙率由31.2%减小到22.4%，0.35水灰比混凝土的孔隙率由25.3%减小到15.2%。生成的大量碳酸钙使结构更加密实，大量的粗孔被细化。

1] 肖佳,勾成福. 混凝土碳化研究综述[J]. 混凝土, 2010(1): 40-44.

[2] 阿茹罕,阎培渝.不同粉煤灰掺量混凝土的碳化特性[J].硅酸盐学报,2011,39(1):7-12.

[3] 宋华,牛荻涛.矿物掺合料混凝土碳化性能试验研究[J].硅酸盐学报,2009,37(12):2066-2070.

[4] 柳俊哲.混凝土碳化研究与进展(1)-碳化机理及碳化程度评价[J].混凝土,2005,193(11):10-13.

[5] Carlos A G G, Hidalgo A, Fraile J, et al. Porosity and water permeability study of supercritically carbonated cement pastes involving mineral addition[J]. Industrial & Engine-ering Chemistry Research,2007,46(8):2488-2496.

[6] Pihlajavaara S E. Some results of the effect of carbonation on the porosity and pore size distribution of cement paste[J].Materials and Structure, 1968,1(6):521-526.

[7] Keshu Wan, Qiong Xu, Yudong Wang. 3D spatial distribution of the calcium carbonat-e caused by carbonation of cement paste[J].Cement & Concrete Composites,2014,45:255-263.

[8] Saeki T, Ohga H, Nagataki S. Mechanism of carbonation and prediction of carbonate-on process of concrete[J]. Concrete Library of JSCE,1991,17:23-36.

[9] 方永浩,张亦涛，莫祥银. 碳化对水泥石和砂浆的结构及砂浆渗透性的影响[J].河南大学学报,2005,33(1):104-107.

[10] Song H W, Kwon S J. Permeability characteristics of carbonated concrete considering capillary pore structure[J]. Cement and Concrete Research, 2007,37(6):909-919.

[11] Bier T. Influence of Type of Cement and Curing on Carbonation Progress and pore Structure of Hardened Cement Pastes[C]. Materials Research Society Symposium Proceed-ings, 1986,85(M):123-134.

[12] Claisse P A, Shaaban I G. Permeability and pore volume of carbonated concrete[J]. ACI Materials Journal, 1999, 96(3): 378-381.

[13] 谢东升.高性能混凝土碳化特性及相关性能的研究[D].南京:河海大学,2005.

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不同强度等级的混凝土碳化特性研究

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