Assessment of the impact of modifier and filler on the physical and mechanical and operational properties of plastering mortars

Abstract

To assessment of the impact of the addition of microsilica on the mechanical properties of the plaster mortar, experimental-statistical modeling was used. A complex of engineering problems based on models describing the change in the technological and physical and mechanical properties of the plaster mortar during the control of the dosages of microsilica and superplasticizing admix was solved. The problem of choosing the optimal dosage of the filler was solved under the condition of the equality of the water-cement ratio and the mobility of the compositions without and with microsilica additive, which was achieved by appropriate adjusting the dosage of the superplasticizing admix on the consumption of microsilica, i.e. the concentration of the superplasticizing admix was dependent on the consumption of microsilica. Analysis of the effectiveness of the addition of microsilica in the entire factor space using the model of relative efficiency was carried out. The areas of optimal compositions of plaster mortars, in which the increased technological and mechanical parameters are performed, have been determined. An assessment of the effect of ultrafine filler on the operating ability of plaster mortars has been carried out. The main indicators were: the value of adhesion of the plaster layer to the concrete base; the strength of the concrete base (“old” concrete); strength of the plaster layer; indicator of water absorption of the plaster layer. The assessment of the frost resistance of the modified plaster mortar was carried out after 20, 40 and 60 cycles of freezing and thawing. It was found that the proposed modification made it possible to increase the adhesion strength of the plaster layer to the base, save the characteristics of the concrete base after exposure to an aggressive environment, increase the strength of the plaster layer and make it less permeable due to the compaction of the structure, and also to reduce the thickness of the plaster layer without losing its protective properties.