Shaping Mortar Parameters in Terms of their Tendency to Form Shrinkage Cracks

Abstract:

The most common reason for the appearance of cracks or delamination of plaster is their too high strength - higher than the strength of the substrate, their low flexibility and high shrinkage during curing. The article presents a study on influences of natural and synthetic polymers with different chemical composition of the physical properties of category CS II mortars. Polymer additives in the form of dry powders were selected for testing. Studies were carried out in two versions: with constant consistence and with a constant w/c ratio maintained. It has been found that modifying mortars with synthetic polymers improves their flexibility and flexural tensile strength. The shrinkage is dependent on the ability of the synthetic polymer to liquefy fresh mortar where the tests were conducted maintaining constant consistence. Similar relationships were determined for cellulose ethers. Also in this case, the increase in the contents of the cellulose ethers increases their tensile strength and decreases the shrinkage. It was found that the impact of cellulose ethers on the shrinkage depends on their surface activity.

• Periodical: Solid State Phenomena (Volume 276)
• Pages: 210-216
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.276.210
• Online since: June 2018
• Authors: Wacław Brachaczek
• Keywords: Multiple Regression, Permeate Water Vapour, SD Value, Silicon Render, Silicone Resin

References

[1] CEB-FIP Model Code 90, CEB Bulletin No. 213/214, (1993).

[2] N. Ignatiev, S. Chatterji, On the mutual compatibility of mortar and concrete in composite members, Cement and Concrete Composites 14(3) (1992) 179-183.

DOI: 10.1016/0958-9465(92)90011-j

[3] K. Kovler, Y. Frostig, On the problem of cracking in plaster layers, Construction and Building Materials 12(5) (1998) 251-258.

DOI: 10.1016/s0950-0618(98)00013-0

[4] A. Klisinska-Kopacz, R. Tislova, Effect of hydrophobization treatment on the hydration of repair Roman cement mortars, Construction and Building Materials 35 (2012) 735-740.

DOI: 10.1016/j.conbuildmat.2012.05.002

[5] J. Mirza, M.S. Mirza, R. Lapointe, Laboratory and field performance of polymer-modified cement-based repair mortars in cold climates, Construction and Building Materials 16(6) (2002) 365-374.

DOI: 10.1016/s0950-0618(02)00027-2

[6] Y. Ohama, Principle of latex modification and some typical properties of latex-modified mortars and concretes, Aci Materials Journal 84(6) (1987) 511-518.

DOI: 10.14359/2463

[7] E. Sakai, J. Sugita, Composite mechanism of polymer-modified cement, Cement and Concrete Research 25(1) (1995) 127-135.

DOI: 10.1016/0008-8846(94)00120-n

[8] Y. Ohama, Handbook of polymer-modified concrete and mortars: properties and process technology, William Andrew.(1995).

[9] A. Beeldens, D. Van Gemert, H. Schorn, Y. Ohama, L. Czarnecki, From microstructure to macrostructure: an integrated model of structure formation in polymer-modified concrete, Materials and Structures 38(280) (2005) 601-607.

DOI: 10.1007/bf02481591

[10] L. Czarnecki, P. Lukowski, Polymer-cement concretes, Cement Wapno Beton 15(5) (2010) 243-258.

[11] V. Morin, M. Moevus, I. Dubois-Brugger, E. Gartner, Effect of polymer modification of the paste-aggregate interface on the mechanical properties of concretes, Cement and Concrete Research 41(5) (2011) 459-466.

DOI: 10.1016/j.cemconres.2011.01.006

[12] X.L. Fu, D.D.L. Chung, Effect of methylcellulose admixture on the mechanical properties of cement, Cement and Concrete Research 26(4) (1996) 535-538.

DOI: 10.1016/0008-8846(96)00028-2

[13] V. Slowik, T. Hubner, M. Schmidt, B. Villmann, Simulation of capillary shrinkage cracking in cement-like materials, Cement & Concrete Composites 31(7) (2009) 461-469.

DOI: 10.1016/j.cemconcomp.2009.05.004