Analysis of Air Voids Evolution in Cement Pastes Admixed with Non-ionic Cellulose Ethers

Abstract

Four cellulose ethers (CEs) were compared for their effects on the pore structure of cement paste using mercury intrusion porosimetry. The experimental results show that the total pore volume and porosity of cement pastes containing the four cellulose ethers are significantly higher than that of the pure cement pastes and the total pore volume and porosity of cement pastes containing HEC (hydroxyethyl cellulose ether) or low viscosity cellulose ethers are low in four CEs. By changing the surface tension and viscosity of liquid phase and the strengthening of liquid film between air voids in cement pastes, CEs affect the formation, diameter evolution and upward movement of air voids and the pore structure of hardening cement paste. For the four CEs, the pore volume of cement pastes containing HEC or low viscosity cellulose ethers is higher with the diameter of 30–70 nm while lower with the diameter larger than 70 nm. CEs affect the pore structure of cement paste mainly through their effects on the evolvement of the small air voids into bigger ones when the pore diameter is below 70 nm and their effects on the entrainment and stabilization of air voids when the pore diameter is above 70 nm.

Keywords

cellulose ethers / cement pastes / pore structure / air voids / diameter evolution

References

[1] Shao ZQ. Cellulose Ethers[M]. 2007 Beijing: Chemical Industry Press.

[2] Plank J. Applications of Biopolymers and Other Biotechnological Products in Building Materials[J]. Applied Microbiology and Biotechnology, 2004, 66(1): 1-9.

[3] Patural L, Marchal P, Govin A, et al. Cellulose Ethers Influence on Water Retention and Consistency in Cement-based Mortars[J]. Cement and Concrete Research, 2011, 41(1): 46-55.

[4] Khayat K H. Viscosity-enhancing Admixtures for Cement-based Materials-An Overview[J]. Cement and Concrete Composites, 1998, 20(2-3): 171-188.

[5] Jiang Z, Cui B, Sun Z, et al. Study on the Properties of Underwater Anti-washout Concrete[J]. Journal of Building Materials, 2000, 3(2): 129-134.

[6] Zhong S, Bao M, Xue M. Rheologic Parameters of Self-compacted Concrete with Polycarboxylate Superplasticizer[J]. Journal of Building Materials, 2006, 9(5): 521-526.

[7] Zhao Q, Zhang Y, Liu C, et al. The Competitive Adsorption Characteristics of Welan Gum and Superplasticizer in Cement Mortar[J]. Journal of Wuhan University of Technology -Materials Science Edition, 2016, 31(1): 131-138.

[8] Zhao Q, Liu C, Qu C, et al. Effect of Delay Released Welan Gum on the Performance of Cement Mortar[J]. Journal of Wuhan University of Technology -Materials Science Edition, 2016, 31(5): 1008-1017.

[9] Zhang Y, Kong X, Gao L, et al. Rheological Behaviors of Fresh Cement Pastes with Polycarboxylate Superplasticizer[J]. Journal of Wuhan University of Technology -Materials Science Edition, 2016, 31(2): 286-299.

[10] Pourchez J, Peschard A, Grosseau P, et al. HPMC and HEMC Influence on Cement Hydrations[J]. Cement and Concrete Research, 2006, 36(2): 288-294.

[11] Pourchez J, Grosseau P, Guyonnet R, et al. HEC Influence on Cement Hydration Measured by Conductometry[J]. Cement and Concrete Research, 2006, 36(9): 1777-1780.

[12] Silva DA, Monteiro PJM. The Influence of Polymers on the Hydration of Portland Cement Phases Analyzed by Soft X-ray Transmission Microscopy[J]. Cement and Concrete Research, 2006, 36(8): 1501-1507.

[13] Weyer HJ, Müller I, Schmitt B, et al. Time-resolved Monitoring of Cement Hydration: Influence of Cellulose Ethers on Hydration Kinetics[J]. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 238 (1–4): 102–106

[14] Ou Z, Ma B, Jian S. Influence of Cellulose Ethers Molecular Parameters on Hydration Kinetics of Portland Cement at Early Ages[J]. Construction and Building Materials, 2012, 26(1): 78-83.

[15] Ou Z, Ma B, Jian S, et al. Influence of Cellulose Ethers Molecular Parameters on Mechanical Properties of Cement Pastes[J]. Bulletin of Chinese Ceramic Society, 2016, 35(8): 2371-2377.

[16] Wang P, Xu Q, Li W. Effect of Hydroxyethyl Methylcellulose on Properties of Cement Mortar[J]. Journal of Building Materials, 2000, 3(4): 305-309.

[17] Silva DA, John M, Ribeiro JLD, et al. Pore Size Distribution of Hydrated Cement Pastes Modified with Polymers[J]. Cement and Concrete Research, 2001, 31(8): 1177-1184.

[18] Jenni A, Holzer L, Zurbriggen R, et al. Influence of Polymers on Microstructure and Adhesive Strength of Cementitious Tile Adhesive Mortars[J]. Cement and Concrete Research, 2005, 35(1): 35-50.

[19] Pourchez J, Grosseau P, Pourchez ER, et al. Impact of Cellulose Ethers on the Cement Paste Microstructure[C]. 10th International Conference and Exhibition of the European Ceramic Society, 2007 Berlin: Germany.

[20] Pourchez J, Ruot B, Debayle J, et al. Some Aspects of Cellulose Ethers Influence on Water Transport and Porous Structure of Cement-based Materials[J]. Cement and Concrete Research, 2010, 40(2): 242-252.

[21] Ou Z, Ma B, Jian S. Pore Structure of Cement Pastes Modified by Non-ionic Cellulose Ethers[J]. Journal of Building Materials, 2013, 16(1): 121-126.

[22] Taylor HFW. Cement Chemistry[M]. 1997 New York: Academic Press.

[23] Keary CM. Characterization of METHOCEL Cellulose Ethers by Aqueous SEC with Multiple Detectors[J]. Carbohydrate Polymers, 2001, 45(3): 293-303.

[24] Ou ZH, Liu G, Huang C, et al. Study on Viscosity Variation of Cement Pastes Modified by Cellulose Ethers[J]. Materials Review, 2016, 30(7): 135-139.

[25] Jiang QZ, Song ZZ, Zhao MF, et al. Surface Activity Agent Science and Technology[M]. 2009 Beijing: China Petrochemical Press.

[26] Wang SR, Li XG, Liu DZ. Surface Activity Agent Chemistry (the second edition)[M]. 2010 Beijing: Chemical Industry Press.

[27] Fu XC, Shen WX, Yao TY, et al. Physical Chemistry (the fifth edition) (2)[M]. 2006 Beijing: Higher Education Press.