Study on water hyacinth ash as partial replacement to cement in concrete mixture/ Ma. Joedyn R. Alegre, John Michael D. Alonde, Alyssa Danielle P. Alzate, Alyssa Nicole C. Bernardo, Maria Ysabel L. Dela Cruz, and Ma. Lourdes S. Urbistondo

Includes bibliography

The study investigated water hyacinth ash as a partial replacement to cement in concrete mixture. To establish the efficiency of the water hyacinth ash as partial cement replacement, the fresh properties and mechanical properties were tested. The researchers used a control group with 100% Portland cement, and a treatment group having four different ratios including 7.5%, 10%, 12.5%, and 15% water hyacinth ash as substitutes for cement. The water hyacinth was collected in a local rice field irrigation pond at Tanza, Cavite. The collected water hyacinth was air-dried for a week before burning using the uncontrolled open-air burning method for 6 hours and was sieved using No. 200 (75 m).The samples produced in this study were in accordance with the ASTM standards. The design mix for an M50 grade concrete was used. The samples were tested using a Compression Testing Machine after the curing age of 7, 14, and 28 days. The result from the WD-XRF performed shows that the WHA contains pozzolanic materials such as Ca0, SiOz, FezOs, and SOs, but in lesser amounts than the Ordinary Portland Cement. The testing of specific gravity of WHA resulted in a value of 2.302 which is lower than the specific gravity of Ordinary Portland Cement used which is 3.12, therefore, the WHA is lighter than the Ordinary Portland Cement. As for the fresh properties, it shows that the addition of WHA affected the slump of the concrete. Based on the slump test made, increasing the amount of the ash replacement decreases the value of slump. The results from the testing of setting time has shown that the cement with WHA replacement has a faster initial setting time and a slower final setting time. The WHA replacement affected the mechanical properties of the samples. On the 28% day of curing, the result shows that the addition of WHA increases the compressive strength and split tensile strength of the concrete, but the peak of compressive strength and split tensile strength was achieved with 12.5% WHA replacement and declines at 15% WIIA replacement. Afer the statistical analysis of the data gathered, it was concluded that the optimum WHA replacement was 12.5%.