Effect of the entrained air void on strength and interfacial transition zone of air-entrained mortar

Abstract

In order to facilitate the development and application of air entraining agents (AEA) in the high performance concrete, entrained air void structure parameters (air void size range from 10 to 1 600 μm) of 28 d sifted mortar were measured by image analysis method. The relationship between the air void size distribution and strength of mortar was studied by methods of grey connection analysis and multiple linear regression analysis. The multiple linear regression equation was established with a correlation coefficient of 0.966. The weight of the affection of hierarchical porosity on the compressive strength ratio was also obtained. In addition, the effect of air voids on the paste-aggregate interfacial transition zone (ITZ) was analyzed by microhardness. The results show that the correlation between different pore size range and the compressive strength is negative. The effect of air void size distribution on 28 days compressive strength is different: under the condition of similar total porosity, with the increase of the porosity of the air void size, ranging from 10 to 200 μm, and the decrease of the porosity, ranging from 200 to 1 600 μm, the average air void diameter and mean free spacing are decreased; as well as the width of ITZ. On the contrary, the microhardness of the ITZ is increased while the compressive strength loss is decreased.

Keywords

air void structure / compressive strength / interfacial transition zone / grey connection / linear regression

References

[1] Yu X M, Mei M R, Ren Q W. Experimental Research about the New Air-Entraining Agent Effect on Frost Resistance of Medium-Low Grade Concrete[J]. Concrete, 2009, 9: 69-71.

[2] Chatterji S. Freezing of Air-Entrained Cement-Based Materials and Specific Actions of Air-Entraining Agents[J]. Cem. Concr. Res., 2003, 25(7): 759-765.

[3] Kim H K, Jeon J H, Lee H K. Workability, and Mechanical, Acoustic and Thermal Properties of Lightweight Aggregate Concrete with a High Volume of Entrained Air[J]. Constr. Build. Mater., 2012, 29: 193-200.

[4] Wang X B, Cai Y X, Zang Z S. The Effect of the Dosage of Air-Entraining Agent on Cement Concrete Rheological[J]. Journal of Hebei Jiaotong Vocational and Technical College, 2010, 7(3): 32-34.

[5] Shi C J. Strength, Pore Structure and Permeability of Alkali-Activated Slag Mortars[J]. Cem. Concr. Res., 1996, 26(12): 1789-1799.

[6] Rao G A. Generalization of Abrams’Law for Cement Mortars[J]. Cem. Concr. Res., 2001, 31(3): 495-502.

[7] Huang D N, Shen W. The Structure and Rheological Characteristic of Fresh Concrete[M], 1983 Beijing: China Architecture & Building Press.

[8] Deo O, Neithalath N. Compressive Behavior of Pervious Concretes and a Quantification of the Influence of Random Pore Structure Features[J]. Mater. Sci. Eng. A, 2010, 528: 402-412.

[9] Older I. Investigations on the Relationship between Porosity, Structure and Strength of Hydrated Portland Cement Pastes:ii.Effects of Pore Structure and Degree of Hydration[J]. Cem. Concr. Res., 1985, 15(3): 401-410.

[10] Kumar R, Bhattacharjee B. Porosity, Pore Size Distribution and in Situ Strength of Concrete[J]. Cem. Concr. Res., 2003, 33(1): 155-164.

[11] Liu Z Q, Schutter G D, Deng D H, et al. Micro-Analysis of the Role of Interfacial Transition Zone in “Salt Weathering” on Concrete[J]. Constr. Build. Mater., 2010, 24(11): 2052-2059.

[12] Hussin A, Poole C. Petrography Evidence of the Interfacial Transition Zone (ITZ) in the Normal Strength Concrete Containing Granitic and Limestone Aggregates[J]. Constr. Build. Mater., 2011, 25(5): 2298-2303.

[13] Ollivier J P, Maso J C, Bourdette B. Interfacial Transition Zone in Concrete[J]. Advanced Cement Based Materials, 1995, 2(1): 30-38.

[14] Razak H A, Chai H K. Near Surface Characteristics of Concrete Containing Supplementary Cementing Materials[J]. Cem. Concr. Compos., 2004, 26(7): 883-889.

[15] Wong H S, Buenfeid N R. Euclidean Distance Mapping for Computing Microstructural Gradients at Interfaces in Composite Materials[J]. Cem. Concr. Res., 2006, 36(6): 1091-1097.

[16] Mindess S, Young J F. Concrete[M], 2005 Beijing: Chemical Industry Press.

[17] Zhang H, Ding J T, Gao P W. Analysis on the Air-Void System Test Methods of Concrete[J]. Low Temperature Architecture Technology, 2009, 31(12): 7-9.

[18] Laskar A I, Kumar R, Bhattacharjee B. Some Aspects of Evaluation of Concrete through Mercury Intrusion Porosimetry[J]. Cem. Concr. Res., 1997, 27(1): 93-105.

[19] Zhang Y J, Zhang X. Grey Correlation Analysis between Strength of Slag Cement and Particle Fractions of Slag Powder[J]. Cem. Concr. Compos., 2007, 29(6): 498-504.

[20] Patton M Q. Qualitative Evaluation and Research Methods[M], 1990 Calif: Sage Publications.

[21] Deng J L. Grey Control System[M], 1985 Wuhan: Huazhong Engineering College Press.

[22] Liu R X, Kuang J, Gong Q, et al. Principal Component Regression Analysis with SPSS[J]. Computer Methods and Programs in Biomedicine, 2003, 71(2): 141-147.

[23] Lv Z T, Zhang L Y. The Statistical Analysis and Application of SPSS[M], 2009 Beijing: China Machine Press.

[24] Wong H S, Pappas A M, Zimmerman R W, et al. Effect of Entrained Air Voids on the Microstructure and Mass Transport Properties of Concrete[J]. Cem. Concr. Res., 2011, 41(10): 1067-1077.