Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: T018
DOI: https://doi.org/10.24326/ICDSUPL2.T018
Published online: 19 April 2023
ICDSUPL, 2, T018 (2023)
Influence of hydrophobic coatings on the durability of aerated concretes
Małgorzata Grzegorczyk-Frańczak1*
1 Civil Engineering Laboratory, Civil Engineering and Architecture Faculty, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland
* Corresponding author: m.grzegorczyk@pollub.pl
Abstract
Polymer microspheres are fine air voids surrounded by a polymer coating, an alternative to traditional concrete aeration technology. In contrast to the air created by traditional admixtures, microspheres are stable over time and do not change their dimensions. This eliminates a series of problems occurring during the application of chemical surfactant admixtures in concrete technology, i.e.: instability of air bubbles, clusters, agglomerations, irregular distribution of bubbles in the mass of the mixture. Unfortunately, any introduction of air into the concrete mixture, including in the form of microspheres, is related to an increase in water absorption and an increase in the overall porosity of the concrete. The aim of the studies presented in this paper is to examine the possibility of using hydrophobic agents based on organosilicon compounds for surface protection of concrete aerated with polymer microspheres. For this purpose, 3 concretes with the polymeric microspheres were made: MSFW-wet polymeric microspheres concrete with a regular shape, MSFS1-dry polymeric microspheres concrete with an irregular shape, MSFS2-dry polymeric microspheres concrete with a regular shape, and WZ-un-aerated reference concrete. All concretes, after the curing process, were subsequently surface modified with 2 different hydrophobic agents silane and an eco-friendly agent that is a biodegradable glyceryl trioleate-modified silane derivative. To determine the effect of hydrophobization on the properties of the aerated concrete, the weight absorption, open porosity and salt crystallization resistance of both hydrophobized and non-surface-modified samples were tested. The effectiveness of hydrophobization was determined by CA contact angle testing. Surface hydrophobization with silane reduced absorption by (0.7-7.3) %, while the application of an eco-friendly agent reduced absorption by weight by as much as (25.2-70.8) %. A decrease in open porosity from 6 to 78% on average was observed, according to the hydrophobic agent used. Coating with silane and tetramethoxysilane increased resistance to salt crystallization by (13-94) % compared to unmodified samples. A goniometer test confirmed the achievement of the highest wetting angles of (100-120)° in hydrophobized concretes. The study showed that the durability of concrete aerated with polymeric microspheres can be effectively improved by using surface hydrophobization with hydrophobic agents based on organosilicon compounds.
How to cite
M. Grzegorczyk-Frańczak, 2023. Influence of hydrophobic coatings on the durability of aerated concretes. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.T018