An examination of recycled Portland cement concrete rich in dolomite and low in calcite obtained from various locations in Ohio

Thermal analysis is used to investigate 30 year old samples of concrete. In this study, thermal analysis data is combined with XRD data. The contents of these concrete samples are identified in terms of portlandite, calcite, dolomite, gypsum, and quartz. However, the calcium carbonate comes from the carbonation of the portlandite, from the fine and coarse aggregate used in the preparation of the concrete, and also from the second stage of the thermal decomposition of the dolomite. In the present study, samples of recycled Portland cement concrete are investigated which were low in calcite but high in dolomite content. The original presence of slag in these samples influences the long term leaching potential of the concrete. Leaching experiments reveal the presence of both calcium and magnesium ions in the leachate.