Materials Science Forum Vol. 1172

Abstract: Marine soils containing shell fragments are typically found in coastal areas and pose a significant problem as they are highly compressible, have low shear strength and settle heavily, hindering infrastructure development. Conventional stabilization methods are often costly and pose a problem for the environment. Alternative solutions are therefore needed to improve the strength of marine soils by sustainable means. Hence, the main aim of this study is to investigate the effectiveness of cockle shell powder (CS) and nanosilica powder (NS) as sustainable stabilization materials to improve the strength properties of soft marine soils. To achieve this, multi-stage consolidated undrained (CU) triaxial tests were conducted on both untreated and treated soil samples, with 0.7% NS, 10% CS and a combined mixture of 10% CS and 0.7% NS. The tests were conducted under different pressure ratios to determine key strength parameters, including cohesion (c) and internal friction angle (φ). The results showed that the treated soils exhibited a significant increase in strength compared to the untreated samples, with improvements of up to more than 50%. The ANOVA results revealed that the inclusion of cockle shell powder and nanosilica powder had a statistically insignificant influence on the cohesions and friction angles of the treated soils due to the limited number of samples tested under each treatment condition. Furthermore, the multi-stage CU method proved to be efficient in estimating strength parameters while minimizing material consumption and testing time, promoting an environmentally friendly approach to soil improvement in marine environments.

Abstract: This paper presents the relationship between crack width and acoustic emission (AE) energy in reinforced concrete (RC) beams subjected to cyclic loading. Two types of RC beams were tested, each reinforced with different tensile bar diameters: 12 mm (Y12) and 16 mm (Y16). The average ultimate loads (P_ult) for beams with Y12 and Y16 were 31 kN and 51 kN respectively. Beams tested under cyclic loading using Y12 and Y16 were labelled FT12 and FT16. Cyclic loading was applied at 80% of the P_ult and tests were continued until failure. A three-point bending test was performed under a sinusoidal load frequency of 1 Hz. AE monitoring was performed with six sensors installed at selected locations on the beams. The results showed that the crack width increased with the number of cycles, with correlation coefficients (R²) of 0.95 for FT12 and 0.93 for FT16, indicating a stronger linear relationship for both beams. Based on the trends in AE energy and crack width, three crack propagation stages were identified, with high AE energy found in both the initial microcrack formation and the final unstable failure stage. The results confirm that AE is an effective tool for early damage detection and fatigue monitoring in RC structures.

Abstract: Concrete is the most widely used construction material, but its environmental impact and reliance on finite resources have driven the need for more sustainable solutions. This research paper presents the optimization of bamboo fiber and wood ash as supplementary materials in concrete to enhance its mechanical performance and sustainability. A powerful statistical technique known as Response Surface Methodology was employed to systematically investigate the effects of varying bamboo fiber and wood ash content on the compressive and flexural strengths of concrete. The optimal combination of 0.36% bamboo fiber and 13.43% wood ash resulted in a flexural strength of 3.227 MPa and a compressive strength of 18.444 MPa, demonstrating the significant potential of these sustainable materials to improve concrete's mechanical properties. The findings of this study provide valuable insights for the construction industry, highlighting the feasibility of utilizing bamboo fiber and wood ash to develop more durable and environmentally friendly concrete mixtures that can contribute to a more sustainable built environment.

Abstract: This study presents a comprehensive investigation into the optimization of burnt clay brick durability using recycled ceramic tile powder as a partial replacement for clay. The research employed a central composite design approach to systematically evaluate the influence of the ceramic powder addition on the water absorption and abrasion resistance characteristics of the bricks. The experimental results demonstrated that the incorporation of 10% recycled ceramic tile powder significantly enhanced the durability of the burnt clay bricks, reducing the water absorption from 15.2% to 8.9% and the abrasion loss from 3.38 mm to 1.59 mm, compared to the control sample. The statistical analysis of the central composite design model revealed a strong correlation between the ceramic powder content and the durability properties, with R-squared values exceeding 93%. The findings of this study highlight the potential of using recycled ceramic tile powder as a sustainable and effective additive to improve the overall performance and durability of burnt clay bricks, contributing to the development of more eco-friendly and durable construction materials.