Effect of redispersible polymer powders on selected mechanical properties of thin-bed cementitious mortars
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1
Centrum Badawczo-Rozwojowe Atlas sp. z o.o. (Research and Development Center, Atlas sp. z o.o.), 2, Kilinskiego St., 91-421
Lodz, Poland
2
Izohan sp. z o.o., 2 Łużycka, 81-963 Gdynia
3
Instytut Techniki Budowlanej (ITB, Building Research Institute), 1 Filtrowa St., 00-611 Warsaw, Poland
Publication date: 2020-09-02
Cement Wapno Beton 25(3) 168-177 (2020)
KEYWORDS
ABSTRACT
Modern mortars are complex multi-component systems. Among
the mortar components, redispersible polymer powders (RDPs)
play a unique role. They improve the rheology of fresh mortar while
providing flexibility and tensile strength after it has hardened. The
impact of polymeric binders on mortar properties has been and is
currently the subject of intensive research. This paper describes
how the use of different redispersible polymer powders affects
cement mortars’ selected properties, i.e., crack bridging ability,
adhesion determined by measurement of tensile strength and
transverse deformation. Results show that all of the RDPs tested
positively affect the properties of the examined system. The most
significant increase in the mortar’s tensile adhesion strength was
observed for the system with vinyl acetate homopolymer, the lower
one for the systems with styrene-acrylic heteropolymers and vinyl
acetate and ethylene heteropolymers. All tested redispersible
polymer powders in the considered system increase the ability to
bridge cracks in cement mortar. However, the smallest increment
is observed for the acrylic homopolymer and styrene-butadiene
heteropolymer. Other RDPs similarly increase the mortar’s cracks
bridging ability under test defined as the ability of the hardened
material (mortar) to stop the spread of cracks without damaging
it. The results obtained for thin-bed cement mortars in terms of
crack bridging ability were evaluated comparing the requirements
for water-impermeable products. All examined RDPs showed a similar effect on the transverse deformation value of cement mortar.