Structure-forming processes of cement composites, modified by sucrose additions

Abstract

The effect of sucrose on the kinetics of cement hardening has been studied. The study was carried out in two comparative ways, one of which had the organic modifier introduced into cement as gauging liquid ("water - 2% sucrose solution"), the other - as suspensions "cement - water - 2% sucrose solution". The products of sucrose corrosion, synthesized in suspensions, were used as addition agents in the "cement - water" system. Suspension-based approach is interesting because of cement modification by introducing the corrosion products of the same cement, which provides setting acceleration and higher composite density. The structurization role of addition agents, containing products of sucrose corrosion of cement, is provided by synergetic influence of several factors: intensive growth of ettringite crystal nuclei - the main reinforcement component of a cement system, reduction of Ca(OH)2 in solid phase of a rock, CSH-gel densifying and plasticizing. The use of sucrose as gauging liquid results in adverse effect for isolation of cement particles by adsorption layers, impeding the hydration, growth and possible coalescence of crystal - the destructurization of the setting system: the rocks, available from cement gauging with 2 % sucrose solution were not set during the whole trial period. The results were interpreted by means of physic-chemical approaches: X-ray phase analysis, IR-spectroscopy, differential thermal analysis.