DRY MIXTURES

UDC 666.9; 691.53

Nevstaev G. V. Doct. Eng. Sc., Professor (RGSU)

Dolgova A. V. Senior Lecturer of the Department of “Research, Design and Construction of Railways”, Rostov State Transport University, Rostov-on-Don, Russia

Alitinform №2 (59) 2020 г. 58-64 p.

Abstract

The influence of redispersible polymer powders (RPP) and low-modulus inclusions on such properties of mortars as ultimate compressive strength, ultimate tensile strength in bending, initial modulus of elasticity and adhesion strength to a concrete base. The tests were carried out after 28 days of hardening under normal conditions (NC) and after 75 freeze-thaw cycles. The effect of RPP dosage in the range of up to 3% of the dry mixture mass on the change in these properties after cyclic freezing – thawing has been studied. The evaluation of frost resistance of mortars was carried out according to the criteria of ultimate compressive strength, change in elastic modulus, change in the coefficient of strength variation. The influence of the RPP dosage on the specified criteria of frost resistance was revealed, the recommended dosages of RPP and LMI for dry building mixtures with standard requirements for frost resistance were proposed.

Key words:

dry building mixtures, redispersible powders, low-modulus inclusions, freeze-thaw cycles, coefficient of variation, frost resistance of the contact zone