Abstract: Concrete remains the most widely used construction material globally; however, its sustainability is increasingly constrained by the high carbon footprint of cement production, excessive extraction of natural aggregates, and the growing accumulation of industrial and plastic wastes. These challenges are particularly acute in developing regions such as Kenya, where highway culvert construction demands large volumes of durable concrete under demanding environmental and loading conditions. This study addresses the limited integration of cinchona industrial waste ash (CIWA) and pulverized plastic waste (PPW) as combined partial replacements for cement and natural sand in structural concrete applications. A laboratory-based experimental program, supported by Artificial Neural Network (ANN) modeling, was employed to evaluate the mechanical, durability, environmental, and economic performance of CIWA–PPW concrete mixes. Concrete properties including workability, compressive, tensile, and flexural strength, water absorption, density, and cost were assessed in accordance with relevant British and European Standards, alongside carbon emission and cost–benefit analyses. Results show that an optimal mix containing 2.25% CIWA and 2.5% PPW (L2) achieved the most balanced performance, meeting Class C highway culvert strength requirements while reducing cement-related emissions by approximately 6.08 kg CO _2/m ^3, diverting up to 25 kg of plastic waste per cubic metre, lowering material costs by about 1.9%, and reducing concrete density by approximately 360 kg/m ^3. The ANN model demonstrated excellent predictive accuracy (R^2≈0.99). The study concludes that optimized CIWA–PPW concrete offers a structurally adequate, cost-effective, and environmentally sustainable solution for highway culvert construction. Policy support, standardization, and further long-term durability and field-scale investigations are recommended to facilitate large-scale adoption.

Keywords: Cinchona industrial waste ash; Pulverized plastic waste; Sustainable concrete; Highway culvert construction; Environmental impact assessment; Cost–benefit analysis; Artificial neural networks.

Title: Cost, Benefit, and Environmental Impact Assessment of Using Cinchona Industrial Waste Ash and Pulverized Plastic Waste as Partial Replacements for Cement and Sand in Highway Culvert Construction

Author: Omach Antony Owuonda, Fundi Isaac Sanewu, Nyongesa Daniel Wekesa

International Journal of Novel Research in Civil Structural and Earth Sciences

ISSN 2394-7357

Vol. 13, Issue 1, January 2026 - April 2026

Page No: 1-13

Novelty Journals

Website: www.noveltyjournals.com

Published Date: 07-April-2026