Properties of fresh and hardened concrete using agro-waste as partial replacement of coarse aggregate – A review

• More than 60 papers on agricultural wastes used as coarse aggregate in concrete are reviewed.
• Properties like physical, mechanical, durability and structural behaviour of all agro-wastes are reviewed.
• Coconut shell showed superior performance among all agro waste in concrete.
• Cockle shells and periwinkle shells can be a useful replacement material for coastal areas.

Use of agricultural waste in construction industry holds a high potential of reducing global environmental pollution. There are a number of agricultural wastes used as a full or partial replacement of coarse aggregate. This paper reviews some of the agro-wastes like date seed, rubber seed, coconut shell, oil palm shell, corn cob, cockle shell, and periwinkle shell. Of the stated materials, maximum experiments have been conducted by using the oil palm shell and coconut shell as lightweight aggregates. However a grave necessity is felt to properly understand and characterise other waste materials as aggregate replacement. This paper compares different physical and mechanical properties of agro-waste and agro-concrete, and also presents their reviews with comparative behaviours. Structural behaviour and thermal conductivity of these materials are also reviewed and compared with controlled concrete. Reviews indicate that both the sea shell, that is cockle shell and periwinkle shell show very good compressive strength, but low slump, and they require more cement paste to become workable owing to their angular and flaky shape. Coconut shell and oil palm shell shows good performance in structural members which can be comparable to controlled concrete. It is felt that further detailed investigations are required for date seed and rubber shield to firmly characterise them and understand their behaviour.