Effects of Amounts and Moisture States of Clay-Brick Waste as Coarse Aggregate on Slump and Compressive Strength of Concrete

Effects of clay-brick waste (CBW) from demolition in construction on slump and compressive strength of concrete were investigated to promote the reuse of such waste at Vietnam for concrete technology towards sustainable development. The replacements of coarse aggregate by CBW were 0, 10, 20, and 40% by volume. To evaluate the effects of moisture states of CBW on properties of concrete, two states of CBW with a size range of 5–25 mm were prepared: (1) under oven-dry condition and (2) under saturated-surface dry condition. Results showed that the higher the replacement of CBW, the lower the slump of fresh concrete. The moisture states of CBW also affected slump of fresh concrete and compressive strength of hardened concrete. Although CBW under saturated-surface dry condition reduced the compressive strength at the age of 3 days, internal water released from CBW promoted the cement hydration after 3 days, leading to an increase in compressive strength of concrete at the ages of 7 and 28 days. Consequently, CBW can be reused as coarse aggregate for making concrete towards sustainable development of construction materials.