Ssebuuma, Francis2026-10-162026-10-162026Ssebuuma, F. (2026). Controlled acid micro-etching of recycled tyre steel fibres via acid activation for interfacial, structural, and water absorption performance of industrial park yard pavers. [Unpublished dissertation]. Busitema University.https://bdears.busitema.ac.ug/handle/123456789/11038DissertationThis study determined the effects of controlled hydrochloric-acid micro-etching and waste tyre steel fibre (WTSF) dosage on fibre–matrix bonding and the mechanical and water-absorption performance of concrete pavers. HCl concentration (0.5–3.0 M) and immersion time (5–120 min) were varied at approximately 25 °C, with percentage mass loss and maximum pull-out force as responses. The best condition within the tested range was 3.0 M HCl for approximately 106 min; predicted responses were 6.04% mass loss and 60.90 N pull-out force, while the reported confirmation values were 5.23% and 58.7 N, respectively. The pull-out model fitted the experimental data (R² = 86.25%) but had weak predictive capability (predicted R² = 4.03%); the selected treatment condition is therefore preliminary and requires additional independent validation. Treated WTSFs were incorporated at 0, 0.25, 0.50, 0.75 and 1.00 wt%. At 28 days, the 0.50 wt% mix recorded the highest reported compressive strength (34.85 ± 0.52 MPa), split tensile strength (4.60 ± 0.00 MPa) and lowest water absorption (1.8%). The reported flexural strength of 48.23 ± 0.25 MPa at 0.50 wt% is retained provisionally but must be independently verified against the raw loads, support span, specimen dimensions and unit conversions. All specimens remained uncracked under one 1 kg drop from 1 m; this only demonstrates resistance under that single low energy condition and does not discriminate fibre-dosage effects. The results show laboratory-scale promise, but they do not establish long-term durability or qualification for heavy-duty industrial service.enOther