Study of influence of the alkaline component on the physico-mechanical properties of the low clinker and clinkerless waterproof compositions

Abstract

The influence of the alkaline component on the physicomechanical properties and the structure of the clinkerless waterproof composition on the basis of Kryvyi Rih blast furnace slag and an alkaline component – sodium hydroxide – have been investigated. High and very high correlation between the compressive strength f of the composition and the alkali – sodium hydroxide – strength A/S has been established. The dependence f on A/S has an extreme wave-like pattern with maxima at A/S = 1.5% and 15-20%, which is explained by the formation of one and two series of hydration products between slag particles similarly to Portland cement-based compositions. It has been established that the hydration products of the composition are predominantly gel-like one, such as hydrosilicate gel and zeolite-like sodium calcium hydroalumosilicates; fewer crystalline hydration products include prismatic and needle-like crystals of complex salts of aluminate phases. The pore size in the composition structure mostly does not exceed 2 microns, although single pores up to 10 microns in size also occur.