Production of clinker and cement using crushed concrete waste.

Old and crushed concrete structures, which have become construction wastes, have a significant impact on the environment. Fine fractions formed in crushing them (mainly as sand) are difficult to reuse for concrete. Laboratory studies have shown that it is possible to replace one or two traditional components of the raw mix for clinker production with sands obtained from crushed concrete. At the Créchy cement plant (Vichy, France), Vicat produced a pilot 3000-ton batch of clinker from the raw mix containing 14.6% of such sand. The production conditions for this clinker and the characteristics of the cement from it were almost the same as for the conventional Portland cement clinker produced at the plant. Another way to recycle the sand from concrete waste is to add it to the cement charge together with the conventional clinker. The tests of 50-kg cement batches containing up to 25% of sand from concrete waste produced at the pilot plant, confirmed the suitability of the materials for the same purposes as those of cements with mineral additives.

Author: L. Izoret

Section: Waste utilization

Keywords: concrete fines, recycling, clinker, cement