This paper presents the study carried out on the utilization of Waste Glass Powder (WGP) as supplementary cementitious material in concrete. The evaluation of the influence of WGP on the mechanical properties of concrete was carried out by casting and testing of concrete samples as per ASTM standards (cylinders and beam elements). The control samples were designed to represent field conditions with a target compressive strength of 20,000 kPa. The Portland cement in concrete was substituted with WGP in proportions of 0%-35% by weight, in increments of 5%. Two curing domains were adopted in the preparation of the test samples to evaluate the effect of pozzolanic material wherein the tested samples were cured for 28, 56, and 84 days. The study results indicated a reduction in compressive strength of concrete up to 10% with partial replacement of cement with 25% of WGP when standard curing of 28 days was adopted. Furthermore, with the same replacement proportion and prolonged curing for 84 days, the gap in strength reduction was reduced by 5%. However, a significant decrease in workability was noted between the control concrete samples and glass powder infused concrete. Furthermore, the Waste Glass Powder Concrete (WGPC) exhibited an improved flexural strength with the modulus of rupture for WGPC being 2% higher than control concrete at the age of 84 days. Based on the results of this study it was concluded that 25% replacement of cement with WGP provides an optimum replacement ratio. Doi: 10.28991/cej-2020-03091620 Full Text: PDF

This paper presents the findings of a study carried out for evaluation of the mechanical behavior of lightweight concrete by the use of lightweight aggregate. Pumice, a rock resulting from cooling of lava, having entrapped air bubbles, has been used as a lightweight coarse aggregate. Evaluation...

Lime column (LC) is an effective method for ground improvement which causes reduction in settlement and enhancement in bearing capacity of soft soils, subsequently resulting in economical foundations. This study investigates the effects of LC on soft soil with the help of laboratory tests. Firstly, basic laboratory tests are performed on natural soil followed by load deformation tests on untreated and LC treated soils. LC effects on natural soil are studied by changing various parameters like shear strength of soil (54 kPa, 32 kPa, 14 kPa), slenderness ratio (4, 5.5, and 7) and spacing to diameter ratio (2, 3). Experimental results show that LC significantly increases load carrying capacity and stiffness for soils having higher shear strength. For soil samples of 54 kPa and 32 kPa, the load carrying capacity increases by 48 and 21% respectively whereas 75% increase in average stiffness (β = 1.75) is observed. However, LC are found to be ineffective at very low shear strength of 14 kPa. In case of group LC, increasing column spacing from 2 to 3D (D: diameter of LC) significantly decreases load carrying capacity of treated soil. It is also observed that increase in LC slenderness ratio causes a decrease in ultimate load carrying capacity.

The inherent vulnerability of beam-column joints to seismic loading and steel congestion are two major research problems connected with beam-column joints of moment-resisting frames. The experimental study presented herein addresses these research questions and seeks to solve them by using Polyvinyl Alcohol based Engineered Cementitious Composite (PVA-ECC) in beam-column joints without transverse shear reinforcement. The study included the manufacture and shake table testing of two 1:3 reduced scale one bay two-story moment-resisting frame models using simulated earthquake motions. To evaluate the performance of ECC beam-column joints without shear reinforcement, two frame models, one with and the other without shear reinforcement in the beam-column joints, were prepared and tested. The acceleration time history record of the 1994 Northridge Earthquake USA was used for the excitation of specimens at different levels to produce progressive damage up to the near collapse state. The observed damage mechanism of tested models was recorded, and the response parameters, including floor displacement and acceleration, were measured. The measured data was processed to develop a lateral force-displacement envelope curve for the supposed prototype frames and calculate their seismic design factors (ductility, overstrength, and response modification). Comparison of the seismic performance parameters of the two prototype frames reveal that the ECC beam/column joint without shear ties performed marginally inferior to the ECC beam-column joints having shear ties but it still achieved a 75% larger R-factor compared with the code specified value.