Compressive Strength Characteristics of Pawpaw Leaf Ash and Bamboo Leaf Ash Blended Cement Concrete

The study determined the physical properties of pawpaw leaf ash and bamboo leaf ash blended cement concrete, the effect of curing age on compressive strength characteristics of pawpaw leaf ash and bamboo leaf ash blended cement concrete, and the effect of percentage replacement of cement with pawpaw leaf ash and bamboo leaf ash blended cement concrete on compressive strength. 100 ×100×100 mm cubes specimens were cast, and the concrete compressive strengths were determined at 7, 14, 21 and 28 days of curing. The control sample, with 0% BLA and PLA replacement, exhibited the highest strength at 28 days but the lowest at 7 days. The sample with 5% BLA and PLA replacement showed an increase in strength at 14 days, a decrease at 21 days, and another increase at 28 days, with the highest strength observed at 14 days. On the other hand, the samples with 10%, 15%, and 20% BLA and PLA replacement demonstrated a consistent increase in strength, although a decrease in strength was observed at 28 days. The experiment revealed that the highest compressive strength was achieved at 28 days with 0% BLA and PLA replacement, while the lowest compressive strength was observed at 7 days with 20% BLA and PLA replacement. These findings indicate that the rate of strength development in BLA and PLA blended cement concrete is slower during the early curing period (7 days) but accelerates during later ages (14 days and 21 days), with a slight decrease at 28 days. In contrast, the control sample without BLA and PLA replacement exhibited slow strength development initially (7 days) but showed faster progress at later ages. Based on the test results, 20% replacement was found to be the optimum level for both compressive strength and workability of concrete with cement partially replaced with BLA and PLA.