Abstract

Buildings constructed with large-panel technology (LPS) before 1990 are increasingly being demolished in Western Europe, and this trend is likely to expand into Central and Eastern Europe due to rising construction activity and limited development space. Despite their age, the concrete from these structures often retains good strength, making it a viable candidate for recycling. This study investigates the reuse of coarse recycled concrete aggregate (RCA) from demolished LPS panels in self-compacting concrete (SCC), a mix known for its high water demand and sensitivity to aggregate properties. The research evaluates whether RCA from LPS should be treated as a distinct material source and examines its effects on cement hydration, free water content, setting times, bleeding, and cross-section homogeneity. While RCA use can reduce the compressive strength of hardened concrete (up to 13% when replacing 30% of natural aggregate), it also improves fresh concrete properties. These include more stable rheology, reduced setting times (by up to 36%), lower bleeding (by up to 40%), and better homogeneity. Strength losses can be mitigated using appropriate pre-treatment and mix design strategies. This study applied a modified Equivalent Mortar Volume (mEMV) method, which improved early compressive strength by up to 10% and 28-day strength by 7%. Given the extensive stock of ageing LPS buildings in Eastern Europe and the ongoing demolitions in the West, RCA offers a sustainable alternative for future concrete production, particularly in SCC, where its benefits in fresh-state behaviour are most pronounced.

Keywords

self-compacting concrete, concrete waste, recycled coarse aggregate, large panel system building.

DOI

10.5703/1288284318152

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Recycled Coarse Aggregate from Large-Panel Demolitions in Self-Compacting Concrete: Performance and Sustainability

Buildings constructed with large-panel technology (LPS) before 1990 are increasingly being demolished in Western Europe, and this trend is likely to expand into Central and Eastern Europe due to rising construction activity and limited development space. Despite their age, the concrete from these structures often retains good strength, making it a viable candidate for recycling. This study investigates the reuse of coarse recycled concrete aggregate (RCA) from demolished LPS panels in self-compacting concrete (SCC), a mix known for its high water demand and sensitivity to aggregate properties. The research evaluates whether RCA from LPS should be treated as a distinct material source and examines its effects on cement hydration, free water content, setting times, bleeding, and cross-section homogeneity. While RCA use can reduce the compressive strength of hardened concrete (up to 13% when replacing 30% of natural aggregate), it also improves fresh concrete properties. These include more stable rheology, reduced setting times (by up to 36%), lower bleeding (by up to 40%), and better homogeneity. Strength losses can be mitigated using appropriate pre-treatment and mix design strategies. This study applied a modified Equivalent Mortar Volume (mEMV) method, which improved early compressive strength by up to 10% and 28-day strength by 7%. Given the extensive stock of ageing LPS buildings in Eastern Europe and the ongoing demolitions in the West, RCA offers a sustainable alternative for future concrete production, particularly in SCC, where its benefits in fresh-state behaviour are most pronounced.