Abstract
As pressure grows for moves toward a low carbon society, an important issue is how to reduce CO2 emissions from the cement manufacturing process. To meet the demands of society, CO2 output is being reduced around the world by adding admixtures to Portland cement. At the same time, the properties of the Portland cement and the amount of admixtures and their quality are unknown to the end user, so problems arise in ensuring stable concrete quality at the construction site. The authors have designed a conduction calorimeter that can help resolve these issues by allowing continuous measurement of hydration heat, which is the heat released when cement reacts with water. Measurement of hydration heat using a conduction calorimeter is a simple method of investigating cement reactions, and it is widely used. However, knowledge of hydration heat output from blended cement systems over the long term is poor and there is a need for it to be studied. In this study, fly ash, limestone powder and blast furnace slag powder are added to the base Portland cement to produce the blended cement. Heat of hydration, compressive strength and total porosity are measured. From the relationship between heat of hydration and compressive strength, a method of estimating compressive strength from hydration heat output is investigated.
