OLWENYI humphrey mudango2026-06-112026-06-112026humphrey M et al., 2026https://bdears.busitema.ac.ug/handle/123456789/5404The sponsors have been very supportive.Uganda faces a critical housing deficit exceeding 2.4 million units, compounded by the environmental and economic unsustainability of conventional fired clay brick (FCB) production. Unfired clay bricks offer a low-carbon alternative, but their inherent low tensile strength and high moisture sensitivity limit adoption in tropical climates. This study systematically optimized bamboo fiber reinforced unfired clay bricks (BFR-UCBs) using Response Surface Methodology with a Central Composite Design (RSM-CCD) across three independent variables: cement content (C: 4.0–10.0%), bamboo fiber content (BF: 0.50–2.00%), and fiber length (FL: 10–20 mm), at three curing ages (7, 14, and 28 days). Clay soil was sourced from Busitema Sub-county (57.4% fines, MDD = 1,878 kg/m³, OMC = 14.2%). Bambusa vulgaris fibers were treated with 2% NaOH to improve matrix bonding and reduce moisture absorption from 18.1% to 12.4%. The RSM-CCD numerical optimization identified the global optimum at C = 8%, BF = 1.75%, FL = 20 mm (composite desirability d = 0.94), yielding a 28-day compressive strength of 5.12 MPa, water absorption of 8.4%, and dry density of 1,875 kg/m³. Comparative testing showed BFR-UCBs outperform artisanal FCBs by 66.75% in compressive strength (6.42 MPa vs. 3.75 MPa) and 48.78% in water absorption resistance, with a coefficient of variation of 2.13% versus 13.36% for FCBs. A significant fiber length × cement interaction confirmed that longer fibers can partially substitute cement without compromising structural performance. BFR-UCBs exceed the EAS 105:2005 minimum of 3.5 MPa and meet ASTM C67 durability criteria, positioning them as a technically viable, environmentally superior substitute for FCBs in Uganda’s construction sector. Keywords: bamboo fiber reinforcement; unfired clay bricks; RSM-CCD optimization; cement stabilization; Uganda; sustainable construction; EAS 105:2005enThesis