Pozzolanic and mechanical properties of Date Palm Seed Ash (Dpsa) concrete

Abstract

This paper presents the findings of a research work conducted on how to improve the mechanical properties of concrete using Date Palm Seed Ash (DPSA) as partial replacement of cement. The DPSA used was obtained by controlled burning of date palm seed in a kiln at a maximum temperature of 630oC for eight hours and air cooled afterwards. The ash obtained was sieved through 75μm sieve and its oxide composition analysed using X-ray fluorescence (XRF) procedures. DoE method of mix design was used to produce concrete ingredients for grade 30N/mm2 giving a water-cement ratio of 0.53. The effect of partial replacement of cement with DPSA on cement paste and concrete using 0, 2.5, 5, 7.5, 10, 15 and 20% DPSA was investigated through consistency and setting times tests, workability test, compressive strength test (at 7, 21, 28 and 56 days curing duration), pozzolanic activity index evaluation and water absorption test. Results show that DPSA has high silicon dioxide (45.50%), aluminum oxide (20.75%) and Iron oxide (7.25%). Findings indicate that the consistency and setting times of cement-DPSA paste increased with increase in the replacement of cement with DPSA. The workability of DPSA concrete decreased with increase in cement replacement. Compressive strength test results show that cement can be replaced with DPSA up to 10% as the compressive strength at 10% replacement is 31.5N/mm2 as against the 31N/mm2 of the normal concrete, at 56 days. The pozzolanic activity index result also show that DPSA concrete meets up the minimum requirement of 75% specified by ASTM C618-15. Also, the water absorption capacity of DPSA concrete at the highest replacement (20%) is 11% less than that at 0%.

Keywords: Cement, Compressive strength, Concrete, Date palm seed ash, Partial replacement, Pozzolana