Adhesion strength to various bases of modified mortars depending on the hardening conditions
Abstract
Adhesion strength to various bases of modified mortars depending on the hardening conditions
Incoming article date: 03.03.2023The influence of the properties of the base and the holding conditions on the adhesion strength to the base of modified building mortars obtained from dry building mixes with a content of 1-3% of redispersible polymer powders has been investigated. A decrease in the adhesion strength of the modified mortar with a standard concrete base was revealed to an average of 0.45-0.8 relative to normal hardening conditions when maintained at elevated temperatures according to GOST R 56387-2018 and to 0.4-0.55 when cyclically heated to 60 ° C, depending on the properties of cement, type and dosage of RPP. The relative strength of adhesion to granite under the same conditions was 0.3-0.65 and 0.2-0.8, respectively. The adhesion strength of modified mortars during hardening under normal conditions relative to the adhesion strength with a standard concrete base is approximately: with silicate brick from 30 to 50%, with ceramic brick from 65 to 80%, with aerated concrete about 50%, with granite from 9 to 18%. The recommended initial dosage of redispersible polymer powders for dry building mixes for heated floors is 1.5%.
Keywords: modified building mortars, redispersible polymer powder, adhesion strength to the base, bending strength, temperature