Main Objective
Investigate OPS as a partial replacement for coarse aggregate in concrete.
UNDERGRADUATE STUDENT
INVESTIGATE THE USE OF OIL PALM SHELL AS PARTIAL REPLACEMENT OF COARSE AGGREGATE IN CONCRETE
Investigating oil palm shell as a partial coarse-aggregate replacement to create lighter concrete while recovering an agricultural by-product.
Kampala, Uganda
Construction Materials
2026
Project Overview
This study evaluated concrete in which oil palm shell (OPS) replaced 0%, 5%, 10% and 15% of natural coarse aggregate. It examined material properties, fresh workability, water absorption and compressive strength to identify whether agricultural waste can be used responsibly in lower-weight concrete.
RESEARCH PROBLEM
Agricultural waste and aggregate extraction need a practical solution.
Conventional concrete depends on quarried coarse aggregate, while palm-oil processing generates large volumes of shell waste. Oil palm shell is a lower-density, porous material that can reduce concrete self-weight, but its effect on water demand, workability and strength must be understood before use.
OBJECTIVES
Research Objectives
Material Properties
Determine the physical properties that affect OPS suitability.
Strength
Evaluate the compressive strength of OPS concrete at each replacement level.
Weight & Absorption
Assess self-weight reduction and water absorption in OPS-modified concrete.
MATERIALS
Materials Used
Portland Cement
Cementitious binder for the concrete specimens.
Oil Palm Shell
Cleaned, crushed and graded agricultural by-product used as partial coarse aggregate.
Natural Aggregates
Locally sourced sand and coarse aggregate for the control and comparison mixes.
Clean Water
Water used for concrete mixing and curing.
METHODOLOGY
Research Methodology
Materials were characterised, concrete samples were cast at four replacement levels and performance was compared through standard laboratory testing.
Material Preparation
OPS was prepared and aggregate grading and specific gravity were assessed.
Mix Proportions
Four concrete mixes used 0%, 5%, 10% and 15% OPS replacement.
Specimen Casting
Concrete cubes were cast for workability, absorption and strength assessment.
Curing
Specimens were cured and tested at 7, 14 and 21 days.
Performance Tests
Slump, water absorption and compressive strength were recorded for each mix.
Result Comparison
Performance trends were compared against the conventional control mix.
KEY FINDINGS
Research Results
Increasing oil palm shell content reduced slump and compressive strength, while lower replacement levels retained acceptable strength.
21.13 MPa
21-day compressive strength at 5% OPS replacement
18.54 MPa
21-day compressive strength at 10% OPS replacement
24.49 MPa
21-day compressive strength of the control mix
190 mm
Slump recorded for 10% and 15% OPS mixes
0.93%
Water absorption of OPS aggregate
5–10%
Recommended OPS replacement range
CONCLUSIONS
Major Findings
A Useful Waste Resource
OPS can provide a productive reuse pathway for palm-oil processing waste.
Strength Reduces at Higher Levels
Compressive strength decreased as the proportion of OPS increased.
Lower Levels Are Viable
At 5% and 10% replacement, the mixes maintained acceptable compressive strength.
RECOMMENDATIONS
Next Steps
Use OPS at lower replacement levels of 5% and 10% for concrete production.
Pre-soak the shells before mixing to reduce their water absorption.
Conduct further durability testing to understand long-term performance.
Investigate further mix proportions and curing periods.