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The theme of this initiative is "Waste to Wealth." Construction materials, particularly concrete, need to have better qualities, including strength, rigidity, durability, and ductility, because Oman's construction industry is expanding. Self-compacting concrete (SCC) has more benefits than regular concrete, including better workability. The major focus of this study is the C30-grade SCC for the control mix, spent catalyst (zeolite catalyst)-based SCC, and the development of the RC beam's flexural behavior employing control and spent catalyst-based SCC. The preliminary study and the main study are the two study outcomes included in this project. Preliminary research involves creating four mixtures with various dosages of 3%, 6%, 9%, and 12% in order to optimize spent catalyst in C30 grade concrete. All of the cubes undergo a 28-day curing test. The cubes' compressive strength is tested in order to establish the ideal dosage, which is 9%. Develop a C30 grade control modified design mix in accordance with SCC and optimize chemical admixtures such as superplasticizer (SP) at different dosages, like 2, 2.5, 3, and 3.5%, using various trials and tests (slump flow, L-box, J-ring, V-funnel, and U-box tests), as well as the optimized dosage of spent catalyst (SC). The main study includes six singly reinforced RC beams with dimensions of 750 (L)×100 (B)×150 mm (D) that were cast and tested in the laboratory. After a 28-day curing period, two specimens were placed under a two-point loading setup, with the remaining two samples receiving the optimum dosages of spent catalyst and superplasticizer. All of the beams were tested using a Universal Testing Machine (UTM) with a 1000 kN capability. From the preliminary study, partial substitution of cement in control concrete of grade C30 using spent catalyst (SC), it was found that the 9% optimum dosage produces greater compressive strength compared to other doses, which are almost 10% rises at 28 days of curing period. Based on a different test, it was discovered that the optimum dose of 3% SP gave closer agreement and satisfied the need for SCC as per the BS standard. The load-carrying capability of the SCC beams is almost 21.7% higher than that of the control beams. Comparing the SCC beams to the control beams, their deflection was reduced by about 26% at the same load level, and their ductility rose by almost 33%. Comparatively to the control beam, the stiffness of 21.6% of SCC also rises. According to test results, the SCC beam performs better in every way when superplasticizer and spent catalyst are used at the recommended dosage. Doi: 10.28991/CEJ-2023-09-05-08 Full Text: PDF

Green concrete is a type of concrete that uses waste materials as one of its ingredients. Hazardous wastes like fly ash and silica fume can be used to partially replace cement in concrete, which varies in physical and chemical properties. On the other hand, the increase in automobiles in urban and rural areas has led to an increase in the number of waste tires, which promotes environmental pollution due to disposal issues throughout the world. This study aims to use waste materials which can partially replace cement and conventional aggregates in the concrete mix. Fly Ash (FA), Silica Fume (SF), and Plaster of Paris (PP) replaced cement, whereas Reclaimed Rubber (RR) partially replaced coarse aggregates by weight. This work is focused on experimentation and simulation of M 40 grade mix using the above four materials. 306 cubes were cast by replacing cement with FA, SF, and PP in 3% increments up to 24%. Similarly, coarse aggregates were replaced with RR using the same proportion. Compression tests were carried out using a Universal Testing Machine. 12% silica fume replacement exhibited maximum strength during individual replacement of materials in concrete, which is selected as the optimum percentage replacement. FA and PP developed ultimate strength at 9% replacement of cement in the concrete mix, which is considered the optimum replacement percentage. A Genetic Algorithm (GA) model was developed using a C++ program to simulate various combinations of FA, SF, PP, and RR based on individual optimum replacement percentage. Hence, 1600 combinations were identified with the above four materials. Hence, GA was used as a tool to simulate the compressive strength of concrete to reduce time and cost. During simulation of combined replacement using GA, very high and very low compressive strength values were neglected, and 32 combinations were selected based on optimum compressive strength values. Finally, five combinations (C1-C5) were recognized, which resulted in higher compressive strength than individual optimum values after simulation. The GA-based numerical results were validated by casting 15 cubes for all the five combinations. 15 beam samples of size 100 150 1500 mm were cast with the above five combinations, cured and tested using a loading frame. A load-deflection curve was plotted, which showed that material replacement increased the flexural strength of the concrete mix. Doi: 10.28991/CEJ-2022-08-05-012 Full Text: PDF

Now days, self-compacting concrete is commonly used in construction industries. The main advantage of using selfcompaction concrete is, achieving the required strength without using the vibrators. In the present study, marble powderwas added with self-compaction concrete and their properties were studied. In Oman, marble factories produced marblepowders around 20-25% of total quantity of marbles by polishing and processing of marble blocks. These factories arefacing problem to dump those powders as landfill. These waste can be used as partially or completely replacement ofcement in concrete. In the present study, marble powders were mixed with C60 grade concrete as partial replacement ofcement (0%, 5%, 01% and 15%). Also flow test and compression test were conducted to study the effect of mixing marblepowder in self-compacting concrete.

The present study depicts on mechanical properties of concrete withSunflower Seed Husk Ash (SSHA) as partialreplacement of cement. Concrete made with Ordinary Portland Cement is the most widely used material in all thecountries. Hence the production of Ordinary Portland Cement is expensive and ecologically harmful. Cement industriesreleasing huge quantity of CO2which pollute the environment. Structural concrete can be produced using sunflower seedhusk ash to meet strength and other requirements. In this project work, various percentages of SSHA added with concreteandthe mechanical properties where studied. The effects of SSHA as partial replacement of cement on concrete propertieswas investigated. Concrete was produced by adding various amount of SSHA (2.5%, 5%, and 7.5%). From the literaturereview it has been noticed that the replacement of sunflower seed husk ash in concrete was very successful in reducing ofunit weight, compressive strength, splitting tensile strength and freezing-thawing resistance. But water absorption rate isincreased after 28 and 90 days. Based on experimental results its physical and mechanical properties show that concreteproduced with sunflower seed husk ash has great potential as a low cost lightweight building material.

Steel scrap is a waste product of steel plate manufacturing industry. Every year huge quantity of steel scrap is produced from drilling the steel plates and other related works. Disposing of those steel scrap is a major issues in Oman and all over the world. Landfill is one of the method for disposing the scraps however it produces soil pollution. Also in Oman, there is no waste separation system, therefore all the waste materials are dumped in soil especially in the desert and it is harmful to the environment. In the present study, steel scrap is added with concrete and the mechanical and physical properties were studied. Three tests were conducted such as slump test to measure the workability of fresh concrete, compressive strength test and corrosion test. In total, four various mixes were prepared with and without steel scrap. The first mix was normal mix without any steel scrap and the remaining three mixes were concrete with adding steel scrap with 1%, 2% and 3%. Based on the compressive strength test results, samples of 1%, 2%, 3% of adding steel scrap shows that the strength was increased for samples with 1% and 2% steel scrap and decreased for 3% steel scrap.

Ferrocement is a composite construction material which consists of highperformance mortar and meshes. Ferrocementis a good technique in the field of strengthening of existing structural members. However, there is a chance for corrosionof steel meshes used for ferrocement, since the cover thickness is very less. In the present study, SBR latex modifiedferrocement technique was introduced for the laminate preparation and the results were compared with normalferrocement. In this work, Styrene-Butadiene Rubber (SBR) polymer was added to the mortar to increase thestrengthening performance and to avoid the corrosion. Six numbers of ferrocement laminate were cast and tested in thelaboratory, out of which three ferrocement laminates with SBR latex and remaining three are ferro-cement laminatewithout SBR latex (normal ferrocement laminate). The sizes of laminates are 550 mm length, 150 mm width and 20 mmthickness. All the laminates were tested under a two point loading system. The ferro-cement laminate with SBR latexshows better strength and improved flexural capacity comparedto the normal ferrocement. The experimental resultsproved that the development of strength, deformability and fracture properties of laminate with SBR latex were morewhen compared to conventional ferro-cement.

The low cycle fatigue behaviour of precipitation strengthened nickel-base superalloy 720Li containing a low concentration of interstitial carbon and boron was studied at 25, 400 and 650 degrees C. Cyclic stress response at all temperatures was stable under fully reversed constant total strain amplitude (Delta epsilon/2) when Delta epsilon/2 0.6%, cyclic hardening was followed by softening, until fracture at 25 and 650 degrees C. At 400 degrees C, however, cyclic stress plateaued after initial hardening. Dislocation-dislocation interactions and precipitate shearing were the micromechanisms responsible for the cyclic hardening and softening, respectively. The number of reversals to failure vs. plastic strain amplitude plot exhibits a bilinear Coffin-Manson relation. Transmission electron microscopy substructures revealed that planar slip was the major deformation mode under the conditions examined. However, differences in its distribution were observed to be the cause for the bilinearity in fatigue lives. The presence of fine deformation twins at low Delta epsilon/2 at 650 degrees C suggests the role of twinning in homogenization of cyclic deformation.