Journal of Structural Engineering

Effect of steel fibers and construction demolition waste on fracture behavior of slag-based geopolymer mortar

Poleboyana Rohit, T.D. Gunneswara Rao, M. Chandrasekhar — Tue, 04 Mar 2025 00:00:00 +0000

This study investigates the effects of Steel Fibers (SF) and Recycled fine Aggregate (RA) from Construction and Demolition waste (CDW) on the mechanical and fracture properties of Steel Fiber-Reinforced Geopolymer Mortar (SFRGM). SF was incorporated at varying volume fractions (0%-1.25%), while natural sand was replaced with RA at levels of 0%, 10%, 20%, and 30%. The study examines compressive strength, splitting tensile strength, and flexural strength, as well as fracture characteristics such as load-deflection behavior, peak load, and fracture energy using three-point bending tests on notched beams. Results show that up to 20% RA replacement caused moderate reductions in compressive, tensile, and flexural strengths, with more pronounced decreases at 30% RA. The inclusion of SF notably improved strength parameters by 20%, 45%, and 80%, respectively, while enhancing ductility and energy absorption. Although RA slightly lowered fracture energy, SF significantly increased it, with a 1% SF content yielding approximately 59 times the fracture energy of the control sample across all mixes. These findings suggest that integrating RA and SF in SFRGM offers a potential alternative to conventional cement-based materials.

Experimental investigations on mechanical properties of lightweight pervious concrete using pumice and microstructure aspects

R. Harshani, C. Chella Gifta, M. Esai Nandhini — Tue, 04 Mar 2025 00:00:00 +0000

This study introduces a novel construction material, pumice-based Lightweight Pervious Concrete (LPC), which combines the benefits of lightweight aggregates, high porosity, and sustainability. Pumice, a naturally occurring volcanic rock, offers low density, high porosity, and pozzolanic properties that enhance the performance of pervious concrete. The study explores the mechanical, hydraulic, and durability characteristics of LPC by analyzing its density, void ratio, permeability, and microstructure. Various mix designs for pervious concrete were tested, categorizing them into two groups: conventional coarse aggregate and pumice. Wet density values for lightweight mixes (LW) ranged from 1440–1480 kg/m³, with dry densities from 1410–1465 kg/m³, significantly lower than Conventional Concrete (CC) mixes, which had wet densities of 2110–2190 kg/m³ and dry densities of 2090–2170 kg/m³. The void content in LW mixes was 22.2–23.87%, higher than the 19.21–19.87% of CC mixes, promoting permeability and groundwater recharge. Permeability tests demonstrated superior infiltration rates in LW mixes, with values up to 20.12 × 103 mm/hr, highlighting their efficacy in stormwater management. Despite lower compressive strength (2.47– 5.99 MPa), LPC exhibited satisfactory performance in lightweight applications. Microstructural analysis revealed pumice’s rough, porous texture, enhancing the C-S-H gel bond while contributing to higher porosity.

Thermal performance of sandwich wall panels with bamboo core

N. Sooriyalakshmi, H. Jane Helena — Tue, 04 Mar 2025 00:00:00 +0000

This study investigates the thermal performance of Sandwich Wall Panels (SWP) incorporating bamboo as the core insulating material. The SWP specimens were made from solid sintered fly ash aggregate concrete with bamboo arranged in various configurations, including full culm, half culm, and checkered culm patterns, alongside a control specimen. Eight specimens were tested to evaluate heat transfer and the rate of heat flow through the different bamboo arrangements, assessing their insulating effectiveness. A custom-designed hot box and heat control system, calibrated with materials of known thermal conductivity (expanded polystyrene, plywood, and newspaper), were used for thermal analysis. Temperature data were monitored in real-time using a Programmable Logic Controller (PLC) and Supervisory Control and Data Acquisition (SCADA) system. The thermal resistance of each pattern was calculated and compared with finite element analysis results from ANSYS, showing a high correlation with an error margin of just 0.5%.

Seismic performance evaluation of reinforced concrete building frame with vertical and plan irregularity

J. Prakashvel, C. Umarani, K. Sathish Kumar, G.V. Rama Rao — Tue, 04 Mar 2025 00:00:00 +0000

Buildings with single or multiple irregularities are highly vulnerable to seismic events. However, there are large number of existing buildings and new constructions with multiple irregularities both in the urban as well as rural areas of developing countries. Earlier earthquake events have demonstrated the failure patterns of the irregular reinforced concrete buildings. In the literature, only few experimental investigations have been reported on the reinforced concrete buildings with multiple irregularities. Hence an experimental investigation is carried out to study the seismic behaviour of reinforced concrete buildings with vertical and plan irregularity by conducting shake table test. The dynamic characteristics of the model building are evaluated. Based on the experimental results, the seismic behaviour of the building with multiple irregularities is studied and the code provisions as per IS1893 on the above irregularities are reviewed. The half-scale model reinforced concrete building is subjected to increasing magnitude of seismic input IS 1893 soft soil earthquake spectrum and the dynamic responses of strain, acceleration, and displacements are analysed and discussed along with the failure modes of the building frame with plan and vertical irregularity in this paper.

Evacuation plan for working personnel while roof concreting formwork failure detected by using smart sensor

D. Kamal Nataraj, L.K. Rex, S. Gururaj, K. Thendral Nangai — Tue, 04 Mar 2025 00:00:00 +0000