Determination of pozzolanic activity of materials by thermal analysis

The results of pozzolanic activity determination using DTA-TG method are presented. This feature was characterised by Ca(OH)₂ residue determination in cement pastes admixtured with siliceous earth, consuming the calcium ions from hydrolysis of cement clinker minerals. The rate of pozzolanic reaction was thus estimated. Some results for fly ash containing pastes were also given. This revised version was published online in August 2006 with corrections to the Cover Date.     

Studies of cementitious systems with new generation by-products from fluidised bed combustion

The rate of heat evolution as well as total heat output are strongly affected by other components of hydrating mixture, apart from neat portland cement, such as slag, fly ash and other industrial by-products; among them the wastes from fluidised bed combustion (FBC) has been taken into account recently. In this study the calorimeter was applied to follow the early hydration of cements produced with these materials. They interact with cement paste in a few ways: as set controlling agent and as active pozzolanic admixtures. Thus the rate of heat evolution/hydration is modified, depending on the composition of clinker and percentage of waste in the mixture. After the series of measurements for clinker-waste mixture hydrated systems also some ‘model’ mixtures were investigated to separate the effects from particular waste components. This revised version was published online in July 2006 with corrections to the Cover Date.