Research Papers - Department of Civil Engineering
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Publication Embargo Durability and mechanical performance of glass and natural fiber-reinforced concrete in acidic environments(Elsevier Ltd, 2025-02-28) Justin, S; Thushanthan, K; Tharmarajah, GThis study investigates the mechanical and durability characteristics of fiber-reinforced concrete when exposed to acidic environments. The research focuses on the effects of adding 1 % of treated coir fibers (TCF), treated rice husk fibers (TRH), and glass fibers (GF), along with 5 % silica fume (SF), to concrete. Experimental results show that the inclusion of these fibers and SF enhances both compressive and tensile strengths, with the most significant improvements observed in GF-reinforced concrete. The durability of the concrete was tested by immersing samples in acidic solutions with pH values of 3 and 5 for 28 days. Ultrasonic Pulse Velocity (UPV) tests indicated that the concrete’s quality remained stable, while compressive strength tests revealed an increase in strength, particularly in samples exposed to pH 5. Sorptivity tests, which measure water absorption, indicated higher initial absorption rates due to the porous nature of fiber-reinforced concrete. However, as hydration progressed, the rate decreased. SEM images show that incorporating silica fume improves the microstructure of the specimens benefitting the strength of the structure. The study concludes that concrete reinforced with GF and SF exhibits superior mechanical properties and durability in acidic environments, making it a promising material for use in harsh conditionsPublication Embargo Mechanical and durability analysis of eco-friendly light weight cement blocks using raw rice husk as a partial replacement for manufactured sand(Elsevier Ltd, 2025-03-08) Thavarajah, L; Sundaralingam, K; Tharmarajah, GThe study investigates the mechanical and durability properties of cement blocks made by partially replacing manufactured sand (M-sand) with raw rice husk (RRH). The rising demand for sand in construction, coupled with the environmental impact of its extraction, has prompted the exploration of alternative materials. RRH, a byproduct of rice milling, offers an eco-friendly substitute for sand. The research examines blocks containing varying proportions of RRH (20 %, 40 %, and 60 %) and compares treated and untreated husks. Key parameters, including compressive strength, tensile strength, density, performance when exposed to heat, and water absorption, were analyzed. The results show that up to 40 % of RRH can be used to replace sand without compromising the blocks' structural integrity. Treated RRH blocks demonstrated better bonding with cement, leading to higher compressive and tensile strengths compared to untreated ones. A 40 % RRH replacement achieved an average compressive strength of 3.57 MPa, surpassing the minimum requirements for non-load-bearing masonry units as per Sri Lankan and Australian standards. However, increasing RRH content to 60 % significantly reduced strength and durability. Additionally, RRH blocks exhibited a decrease in density, offering advantages in terms of transportation and handling. Water absorption increased with higher RRH content due to its porous nature yet remained within acceptable limits for treated blocks. These findings suggest that RRH can be a sustainable alternative to sand in masonry applications, especially in rural and eco-conscious construction.Publication Embargo Durability and mechanical performance of glass and natural fiber-reinforced concrete in acidic environments(Elsevier, 2025-02-28) Justin, S.; Thushanthan, K; Tharmarajah, GThis study investigates the mechanical and durability characteristics of fiber-reinforced concrete when exposed to acidic environments. The research focuses on the effects of adding 1 % of treated coir fibers (TCF), treated rice husk fibers (TRH), and glass fibers (GF), along with 5 % silica fume (SF), to concrete. Experimental results show that the inclusion of these fibers and SF enhances both compressive and tensile strengths, with the most significant improvements observed in GF-reinforced concrete. The durability of the concrete was tested by immersing samples in acidic solutions with pH values of 3 and 5 for 28 days. Ultrasonic Pulse Velocity (UPV) tests indicated that the concrete's quality remained stable, while compressive strength tests revealed an increase in strength, particularly in samples exposed to pH 5. Sorptivity tests, which measure water absorption, indicated higher initial absorption rates due to the porous nature of fiber-reinforced concrete. However, as hydration progressed, the rate decreased. SEM images show that incorporating silica fume improves the microstructure of the specimens benefitting the strength of the structure. The study concludes that concrete reinforced with GF and SF exhibits superior mechanical properties and durability in acidic environments, making it a promising material for use in harsh conditions.