Browsing by Author "Kulasuriya, C"

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Investigating the mechanical and durability properties of locally sourced fly ash-based ternary cement paste to increase OPC replacement
(Emerald Publishing, 2026-07-07) Gamage, O; Kulasuriya, C; Perera, S V T J
The mechanical and durability performance of fly ash (FA)-based ternary blended cement pastes was investigated in an attempt to increase ordinary Portland cement (OPC) replacement while maintaining comparable strength and improved durability. This paper provides region-specific experimental data using locally sourced FA from Sri Lanka and imported ground granulated blast-furnace slag (GGBFS). A control mix (100% OPC), two binary blends and six ternary blends were tested for compressive strength at 3, 7 and 28 days, along with water absorption and resistance to sulfuric acid after 28 days. The results showed that OPC specimens achieved the highest early strength, while ternary blends with 25% and 40% OPC replacement achieved comparable 28-day strengths of 82.7 ± 4.8 MPa and 76.2 ± 3.2 MPa, respectively. GGBFS contributed to early strength gain, whereas FA enhanced long-term strength. Durability was improved significantly in the ternary blends. The F15S10 blend, with a higher GGBFS content, showed the greatest sulfuric acid resistance (4.8 ± 0.15% weight loss), while the F40S10 blend, with higher FA content, exhibited the lowest water absorption (6.0 ± 0.18%). Overall, ternary blends with 40% OPC replacement and low FA content are recommended for achieving balanced strength and superior durability in cement paste applications.
Open Access
Mechanical Properties of OPC-Fly Ash Blended Cement Mortar Samples Utilizing Fly Ash from Sri Lankan Power Plants
(Faculty of Engineering, 2025-09-09) Maduwantha, N; Kulasuriya, C
This paper presents findings of an investigation of the compressive strength and water absorption of fly ash blended cement mortar samples made using fly ash (FA) generated in power plants in Sri Lanka. Ordinary Portland Cement (OPC) was substituted partially by 10%, 20%, 30% and, 40% of FA by weight. The control mixture was made up entirely of 100% OPC. The ratio of Cement is to sand was 1:2.75 by volume. Three water to binder ratios were used in preparing mortar samples as 0.375, 0.4, and 0.425. A total of 180 mortar cubes of 50mm x 50 mm x 50mm were prepared and the mortar cubes were water cured. The mortar samples were tested for water absorption at age of 28 days and compressive strength at the ages of 3, 7, and 28 days. The test results show that water absorption increased with FA content, while compressive strength decreased slightly at early ages but remained within an acceptable range. At 28 days, FA replacement had no significant negative impact on strength, and the water absorption was inversely related to compressive strength and density. These findings indicate that OPC can be partially replaced by up to 40% FA without compromising mechanical performance, offering benefits in reducing CO2 emissions, conserving energy, and promoting sustainable construction materials.