Concrete is a composite material of cement, water, fine aggregate, and coarse aggregates. Among these, cement is the costliest component due to its energy-intensive manufacturing process, which produces significant carbon dioxide emissions and contributes to global warming. To address this issue, the research explores alternative materials like water hyacinth for concrete production, as they
... [Show full abstract] require less energy and reduce greenhouse gas emissions. Concrete construction sites also face challenges related to the flow of concrete, its weight, and noise pollution from vibrating equipment used for compaction. This research investigates the effect of superplasticizers on the properties of concrete incorporating water hyacinth ash and superplasticizer. The study examines concrete properties with varying proportions of cement replacement by water hyacinth ash (0%, 5%, 10%, and 15% by weight) and the addition of SP500 superplasticizer in a C-25 concrete mix. The slump test measurements for concrete samples containing 0%, 5%, 10%, and 15% water hyacinth ash were 31 mm, 46 mm, 61 mm, and 83 mm, respectively, at a constant water-cement ratio. In addition, the 28th day of compressive strength with 0%, 5%, 10%, and 15% water hyacinth ash as cement replacement were 30.5 MPa, 31.04 MPa, 32.12 MPa, and 28.21 Mpa respectively. Furthermore, an increased percentage of water hyacinth ash in the cement replacement led to slightly lower water absorption in the concrete. This suggests that the voids in the water hyacinth ash replacement concrete are less porous compared to the control mix concrete. The optimum quantity of water hyacinth ash (10% C was determined using the Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS) method. The experimental results demonstrate that incorporating superplasticizers with the optimal amount of water hyacinth ash significantly improves the workability, strength, and durability of concrete.