Main Objective
Evaluate the effect of powdered Gum Arabic on normal concrete workability, strength and chemical composition.
COMPLETED RESEARCH
The Effect of Powdered Gum Arabic as an Additive on Concrete
Evaluating powdered Gum Arabic as a natural, locally available additive for improving the workability and chemical behaviour of normal concrete.
Kampala, Uganda Construction Materials 2026
Project Overview
This study investigated powdered Gum Arabic as a natural additive in C25 normal concrete. Four mixes containing 0%, 0.5%, 1.0% and 1.5% Gum Arabic by cement weight were tested for slump, compressive strength at 7, 14 and 28 days, and chemical interactions using FTIR analysis.
RESEARCH PROBLEM
Concrete needs accessible, lower-impact admixtures.
Conventional chemical admixtures can be costly and less sustainable. Gum Arabic is a biodegradable natural biopolymer, widely available across the African Gum Belt, but its powdered use in normal concrete is not fully understood. This research tests its impact on fresh, hardened and chemical concrete properties.
OBJECTIVES
Research Objectives
Workability
Determine slump for concrete mixes containing different Gum Arabic dosages.
Compressive Strength
Assess strength development at 7, 14 and 28 days.
FTIR Analysis
Identify chemical interactions between Gum Arabic and cement hydration products.
MATERIALS
Materials Used
Portland Cement
The main binder used in C25 concrete production.
Powdered Gum Arabic
A natural Acacia-tree biopolymer used from 0.5% to 1.5% by cement weight.
Natural Aggregates
Fine and coarse aggregate used in a 1:2:4 control mix.
Clean Water
Water mixed with Gum Arabic before being added to dry ingredients.
METHODOLOGY
Research Methodology
Controlled C25 concrete specimens were batched, cast, cured and tested to compare Gum Arabic dosages.
Mix Proportions
Control, 0.5%, 1.0% and 1.5% Gum Arabic mixes were prepared.
Material Mixing
Gum Arabic was mixed with water before combining with dry concrete ingredients.
Specimen Casting
Concrete cube specimens were cast under standard laboratory conditions.
Curing
Samples were cured for 7, 14 and 28 days.
Performance Tests
Slump and compressive strength were measured for each concrete mix.
FTIR Review
Infrared spectroscopy assessed functional groups and cement–Gum Arabic interactions.
LABORATORY TESTS
Experimental Tests
Slump Test
Compressive Strength
FTIR Analysis
KEY FINDINGS
Research Results
Gum Arabic steadily improved workability but did not exceed the control mix in measured compressive strength.
12 → 16 cm
Slump increased from control to 1.5% Gum Arabic
1.0%
Best 28-day strength among Gum Arabic mixes
12 MPa
28-day strength for the 1.0% Gum Arabic mix
15 MPa
28-day strength of the control mix
980–1000 cm⁻¹
FTIR Si–O peak linked to C–S–H formation
1.5%
Highest workability but lowest 28-day strength
CONCLUSIONS
Major Findings
Improves Workability
Increasing Gum Arabic dosage increased slump and ease of handling in fresh concrete.
Dosage Matters
Higher dosages reduced measured compressive strength; 1.0% gave the best strength of the modified mixes.
Natural-Admixture Potential
FTIR confirmed Gum Arabic coexisted with cement hydration products, supporting its controlled use as an eco-friendly additive.
RECOMMENDATIONS
Next Steps
Use low to moderate Gum Arabic dosages where workability is the main need.
Optimise dosage to balance fresh workability and compressive strength.
Study long-term durability, permeability and abrasion resistance.
Use SEM, XRF or related techniques for deeper chemical characterisation.