MATEC Web Conf.
Volume 174, 20183rd Scientific Conference Environmental Challenges in Civil Engineering (ECCE 2018)
|Number of page(s)||9|
|Section||Material Engineering, Waste Management in Civil Engineering|
|Published online||26 June 2018|
Influence of the fly ash and the prior freezing and thawing on the sulphate resistance of cement mortars
Department of Civil Engineering and Architecture, Kielce University of Technology, al.1000-lecia PP 7, 25-314 Kielce, Poland
* Corresponding author: firstname.lastname@example.org
The use of fly ash for the production of cement is a typical example of the utilization of by-products (waste) from various fields of production in construction, a significant reduction of CO2 emissions and reduction of energy consumption. However, in order to be able to determine the suitability of this additive in construction, it is necessary to examine the durability of cement composites with fly ash in various, often complicated, destructive environments. There are known publications regarding the durability of concretes with fly ash in individual environments. However, in natural conditions, several destructive environments are common at the same time. The article presents an attempt to reproduce natural conditions. This paper presents the results of sulphate expansion tests of air-entrained (AE) and non-air-entrained (nAE) Portland and fly ash cement mortars subjected to prior freezing and thawing. Despite significant strains experienced during freeze-thaw cycles, unlike the non-air-entrained Portland cement mortars, the non-air-entrained mortars made of fly ash cement did not exhibit any significant expansion when exposed to Na2SO4. For 17 months no expansion was found in the air-entrained mortars made of either of the cement types when immersed in Na2SO4 solution after freezethaw cycles. The results of the SEM and EDS analyses showed that gypsum and ettringite were the sulphate attack products in all the mortars. The highest amounts of ettringite were found in air voids.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).
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