Construction Technologies and Architecture Vol. 8

Abstract: Soft clay soil is well known to deform and fail beneath a light surcharge load and being described via high compressibility, low shear strength, and high content of water. The objective of the present study is to determine the optimum okra tips that can be added to stabilize soft clayey soil. Several tests were conducted to determine how varying percentages of okra two ends plants (3, 6 and 9%) for all additives to the dry weight of soil affect the results. The experimental work is used to get the percent of consistency limits, compaction, consolidation, and unconfined compressive strength of the two okra ends increased significantly over time until the improvise continuously decayed. As per the research results, adding, 9%, okra tips stabilizer increased the shear strength and efficiently bonded soil particles together, of resulting in the best engineering qualities. Raising the end content of okra leads to a 57 percent increase in the unconfined compressive strength in content 9 % okra tips.

Abstract: There is a need for railway systems and upgrade their infrastructure to meet the future growing demand. This would expand the railway network by planning new track routes to increase the efficiency of railway transportation by running behavior of high train speeds between urban cities. The track/ballast; sleepers; and subgrade foundation system are important superstructure parts that need to be upgraded and improved to withstand high train speeds. A numerical finite element technique significantly benefits in simulating the impact of the dynamic response and predicting the deformation and stress distribution in the railway ballasted system. A three-dimensional finite element program PLAXIS ver. (20) have been utilized in this research to analyze the track of complex behavior under train loading. The vertical displacement of 3.8 mm was obtained at the rail/wheel contact point and greater than at the ballast embankment by about (19%) and (37%) for the subgrade foundation. Also, the maximum value of vertical displacement corresponds with the movement path of the train load is reduced laterally as the distance from the track centerline increases. The maximum vertical acceleration of 15.2 m/s² was obtained at surface points under track loading and decreased gradually with increased depth below the ballast embankment layer to reach a minimum value of 1.2 m/s². The vertical deformation was 1.3 mm, 2 mm, and 3.9 mm for 40 km/hr, 50 km/hr, and 60 km/hr respectively, and increased rapidly to 15 mm for train velocity greater than 70 km/hr due to the significant increase in train vibration level at higher speed. A critical train speed of 70 km/hr was observed that promoted the level of vibration and magnified the area of influence.

Abstract: In recent decades, fiber-reinforced polymer (FRP) is being used more and more to make concrete structures stronger. In this study, nonlinear finite element (FE) analysis was used to model and compare the influence of curvature performance on the behavior of the simply-supported RC curved soffit reinforced girders strengthened with fiber-reinforced polymer plates (CFRP) with a curve height of 5 to 130 mm. In this study, two models with different heights of curve (5 and 130 mm) and references for each model were used. Each model had dimensions that were similar to those of the models used in the program in terms of cross-sectional area and effective span. Simulations were done on the girders to find out how the load moved in relation to the mean range, the failure load, and the failure mode. This was done so that the effect of curvature on the performance of this type of structural element could be understood. The results show that the girder of height of curve is 5 mm more than 130 mm of the analytical ultimate load compared with that experimentally with a difference of only 4.5%, and 4.2% respectively. The load-displacement curves of the experimental tests were accurately simulated with the help of a nonlinear finite element model.

Abstract: Due to the importance of the joists slab system as an excellent solution for increasing span demands in different building types, investigating its properties becomes essential for different researchers. The effects of numerous parameters on the structural behaviour of the joists slab system, whether it was a waffle, ripped, or composite sections were reviewed in this paper from past studies. This study aims to determine the most effective parameters for the joist's system loading capacity. The main conclusions were that the slab thickness and joist height were the critical parameters for increasing the load capacity and stiffness of the slab. Furthermore, a small opening in the slab was more efficient in reducing the punching shear effect than larger openings. While providing stiffening rips around the opening was more effective in rose load bearing and reducing deflection than strengthening by carbon fibre sheets.

Abstract: Geopolymer is an innovative cement substitute constructed of alkali-activated cementitious materials (AACMs). Researchers interested in improving concrete's structural resistance, toughness, and flexure tensile strength have turned their focus to geo-polymer concrete binders. To completely understand how geopolymer binders act under these circumstances, it is necessary to investigate their behavior when exposed to multiaxial stress states. The purpose of this review is to examine geopolymer cement in depth and to get a better understanding of its mechanical characteristics. In this analysis, we see that Geopolymer concrete, in particular its compressive and tensile strengths, provides higher resilience. GPC is an eco-friendly material since it reduces emissions and requires less water for curing. Incorporating hybrid polypropylene and steel fibers to ternary mixed geopolymer concrete improves its mechanical qualities.

Abstract: Cementing around the casing in oil and gas wells provides proper zonal isolation, holds the casing in place, and prevents fluid migration is an important part of the completing process and well plugging for abandonment. A reliable cement rheology prediction is central to the success of oil well-cementing operations. Properties of the rheological are plastic viscosity and yield stress by using advanced shear-stress/shear-strain controlled Viscometer with using Ground Granulated Blast Furnaces Slug, and Superplasticizer investigated. The effect replacement of Class G cement according to API [1]. (American petroleum institute) classification is performed at different rates. (15%-75%) Blast Furnaces Slag (GGBFS) at intervals of 15%. Further, by using different curing conditions (moist curing and @38°C, @60°C water path curing chamber). The results show that blended cement with 45% of GGBFS has significantly increased in compressive strength more than unblended cement type G. This happened because the fine micro GGBS influences the heat of hydration through the pozzolanic reaction and the effect of superplasticizer. The double effect of GGBS and Superplasticizer on the plastic viscosity and yield point, the linear relationship between shear stress and shear rate, by using Bingham plastic Fluid Model, the slurries act as Newtonian behavior at high shear.

Abstract: The issue of waste accumulation exists around the world, particularly in the densely populated regions. These waste materials not biodegradable in nature, so it is left as stocks or dumped illegally. The burning millions of tons of waste tires creates great risk. To prevent the hazardous effect of produced chemical gases (CO₂) through combustion processes, many research attempts to use huge amounts of rubber waste in concrete mixes. In this paper, properties that are both fresh and hardened of self-consolidating concrete with different sizes of waste tires rubber and micro steel fibers were investigated. The various sizes of waste tires rubber were utilized in place of coarse and fine aggregates, limestone (Al-Gubra) and silica fume after obtaining a rubber size close to the size of each material that has been replaced. Coarse and fine aggregates were replaced with chip and crumb rubbers (20% and 10% by weight). Al-Gubra and silica fume were replaced with ground and finely ground rubbers (50%, 25%, and 12% by weight). The experimental results showed that the fresh properties of self-consolidating concrete had been adversely affected by incorporating micro steel fibers and scrap tires rubber, but remained within the European Federation of National Trade Association Representing Concrete (EFNARC). The results of tests also showed that the mechanical properties decrease when used rubbers as aggregates. However, the results demonstrated that the compressive as well as splitting tensile strength of specimens increased by replacing lime stone dust and silica fume with rubbers. The increases were (12.2-28.0) % and (11.6-41.9) % for compressive strength and splitting tensile strength, respectively.