Assessment of the effect of partial replacement of cement with waste glass powder on the perfomance of water hyacinth petiole-cement insulation boards

Abstract

The growing demand for sustainable construction materials has heightened interest in developing environmentally friendly insulation products from waste resources. This study investigated the production and performance of insulation boards made from water hyacinth petioles (WHP) and waste glass powder (WGP) as a partial replacement for cement. Water hyacinth served as the fibrous component, while waste glass powder was incorporated to reduce cement consumption and promote waste recycling. Although water hyacinth petioles and waste glass powder have each been investigated separately as partial cement replacements, their combined use in a single insulation board, evaluated in both pulp and staple particle forms, has not previously been studied. WHP samples were collected from Port Bell, prepared, dried, and separated into pulp and staple particles. Waste glass collected at Makerere University was cleaned, crushed, and sieved to a fine powder. Composite boards were produced using a 60:40 WHP-to-binder ratio, with WGP replacing cement at 0%, 10%, 20%, 30%, 40%, and 50% by weight. The samples were cast, compacted, cured under laboratory conditions, and tested for bulk density, water absorption, thickness swelling, flexural strength, and thermal conductivity. Results showed that increasing WGP content affected the boards' physical, mechanical, and thermal properties. Thermal conductivity ranged from 0.105–0.046 W/mK for P-panels and 0.098–0.033 W/mK for S-panels, indicating improved thermal insulation performance at higher WGPreplacement levels. Water absorption and thickness swelling generally decreased at moderate WGP contents, while flexural strength improved due to better particle packing and matrix densification. The cost-effectiveness analysis showed that production costs increased with partial replacement of cement by WGP, rising from UGX 30,511 to 53,881 per square meter due to reduced cement consumption. Moderate WGP replacement levels (10%–20%) provided the best balance between cost and performance, making the boards economically viable compared with conventional materials such as MDF, cement boards, and gypsum boards. The study concluded that WHP–cement–WGP composite boards have strong potential as lightweight, low-cost, and sustainable thermal insulation materials. The findings have practical implications for sustainable construction by promoting the use of invasive water hyacinth in valueadded products, reducing reliance on cement, and supporting domestic waste management by recycling waste glass into useful construction materials.