Cementitious and recycled materials that have the potential to improve various properties of concrete have attracted the attention of many researchers recently. Different types of cementitious and recycled materials seem to possess certain unique properties to change cement concrete. This experimental study aims to investigate the impact of ground granulated blast furnace slag (GGBFS) and corn cob ash (CCA) as a partial replacement material for Portland cement (PC) and fine aggregate (FA), respectively, on fresh and hardened concrete properties, as well as the embodied carbon of concrete. The concrete mix was blended with 5-20% of GGBFS and 10-40% of corn cob ash, both individually and combined. A total of 300 concrete specimens were made to achieve the targeted strength of 25 MPa at a 0.50 water/cement ratio and cured at 28 days. It is observed that the workability of fresh concrete is lowered as the dosages of GGBFS and CCA increase in the mixture. Moreover, the compressive and split tensile strengths are augmented by 10.94% and 9.15%, respectively, at 10% of GGBFS by the weight of PC at 28 days. Similarly, the compressive and split tensile strengths are augmented by 11.62% and 10.56%, respectively, at 30% of CCA by the weight of FA at 28 days. Moreover, the combined use of 10% of GGBFS as a cementitious ingredient along with 30% of fine aggregate replaced with CCA in concrete provides the highest compressive and splitting tensile strength, with 16.98% and 13.38% at 28 days, respectively. Furthermore, the density and water absorption of concrete were reduced with increasing dosages of GGBFS and FA in concrete at 28 days. In addition, the embodied carbon and energy were also reduced as the replacement content of GGBFS along with CCA increased in concrete. It is concluded that 10% of GGBFS and 30% of CCA are the optimum percentages for structural applications to reduce the use of cement as well as the cost of the project.
In recent years, there has been great concern about introducing new supplementary cementitious materials (SCM) in place of Portland cement (PC) in concrete. This study aims to investigate the behavior of sugarcane bagasse ash (SCBA), metakaolin (MK) and millet husk ash (MHA) as SCM with various proportions in concrete. The SCBA, MK and MHA are available in abundant quantities and considered as waste products. On the other hand, cement production emits a lot of toxic gases in the atmosphere which causes environmental pollution and greenhouse gases. Thus, SCBA, MK and MHA might be utilized as cementitious material in concrete for sustainable development. The effect of SCBA, MK and MHA as SCM on the fresh, mechanical properties and embodied carbon of concrete was evaluated experimentally. A total of 228 concrete specimens were prepared with targeted strength of 25MPa at 0.52 water-cement ratio and cured at 28 days. It is found that the compressive strength and split tensile strength were enhanced by 17% and 14.28% respectively at SCBA4MK4MHA4 (88% PC, 4% SCBA, 4% MK and 4% MHA) as ternary cementitious material (TCM) in concrete after 28 days. Moreover, the permeability and density of concrete are being reduced while utilizing of SCBA, MK and MHA separately as SCM and combined as TCM increases in concrete at 28 days respectively. Moreover, the workability of fresh concrete was decreased with the increase of the percentage of SCBA, MK and MHA separately as SCM and together as TCM in concrete. In addition to that, the use of SCBA, MK and MHA individually as SCM and combined as TCM in concrete can reduce the total carbon footprint while reducing the overall cost of concrete manufacturing.
The Jacket platform needs gas and diesel to run its turbines, and in the end, they produce catastrophic emissions annually. The environmental concerns regarding these platforms have forced us to utilize an alternative source of energy that is sustainable and clean. In this study 51 locations, are of interest where oil and gas activities are in progress at present in the shape of a jacket platform or pipelines. The significant wave height and wave period scatter diagram data are collected from the platforms in the South China Sea. The linear wave theory is used to find the wave power. The given time period is converted into equivalent time period first before wave energy is determined. The study shows that location no. 20 is the ideal location to deploy the wave energy converter Pelamis P2 with a potential mean wave power of 6.61 kW/m A single unit of Pelamis P2 can produce on an average electricity output of 91.37 kW/m including, the losses and machine efficiencies, whereas a wave farm can generate an average output of 62 GWh/ yr. The electricity supply of 70.3 % of the minimum and 14.1 % of the maximum energy demand, while using only wave energy converter. If hybrid wind and wave energy system is used, then energy production will increase. The results show that the wave farm could also reduce the use of natural gas up to 17.6E06 m 3 / year, avoiding the emission of 12000 tonnes of CO and 54000 tonnes of NOx annually, and can save up to RM 20 billion annually with the reduction of natural gas emissions.
Composites are usually brittle materials and have low impact properties. Structural dimensions, stacking sequence, ply materials, ply thicknesses and ply angles are standard variables that influence composite‘s performance against impact loads. Stacking sequence in hybrid laminates affects the failure and impact resistance. Failure mechanisms at the low‐velocity impact of a rigid object in hybrid laminates are complex, and the subsurface damage in a composite laminate cannot be detected directly. However, various simulation platforms make it easy to see the impact damage between the plies of laminate. This paper numerically investigated the effect of stack sequence and hybridization of two fiber types against low‐velocity impact. The current study adopted four‐layer composite laminates of carbon and glass fiber layers with a stacking plan [C/C/C/C], [C/G/C/G] and [G/C/G/C], having lay‐up angles as [0°/45°/−45°/90°]. Keeping the impactor mass and the incident velocity constant, the laminates were subjected to low‐velocity impact. The damage contours for a failure mode were recorded and compared at the ply level. The numerical study resulted in impact imitations showing comparisons of the damage contours using Hashin failure criteria. Hybrid laminates display better performance in absorbing impact energies; however, hybrid laminates experienced more subsurface damage due to more impact energy absorption.
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