Properties of Hardened Concrete Containing CBA Ash and FCS as Partial Sand Replacement

A large amount of coal bottom ash (CBA) is being discharged from thermal power plants and has been making serious environmental pollution. Meanwhile, fine coconut shell (FCS) is an agricultural waste and is available in plentiful quantities throughout tropical countries worldwide. In many countries, coconut shell is subjected to open burning which contributes significantly to CO2 and methane emissions. Both of these materials are essential to utilize the CBA and FCS to reduce environmental pollution. Therefore, this study aims to determine the properties of combination of these materials as partial sand replacement. CBA is slow in pozzolanic activity of coal bottom ash which is suitable for partial replacement sand. Meanwhile, FCS is lightweight material with high density in porous filler.  Concrete designed for 30 MPa strength at 28 days curing age and 0.50 of water-cement ratio in this study. The percentage of CBA used is 5%, 10%, 15% and 20%, while the percentage of FCS is 2%, 4%, 6% and 8% where it has been replaced by volume replacement. The specimens were cured in water for 7, 28, 56 and 90 days curing ages before compressive and splitting tensile strength test are conducted. It can be concluded that the density of the concrete decreased, compressive and splitting tensile strength show the improvement with the utilization of CBA and FCS in concrete. In addition, the percentage of water absorption increased as both of CBA and FCS absorb the water. This study shows that an optimum percentage of CBA found is 10% and FCS is 6% for this study

Effect of water to cement ratio and replacement percentage of recycled concrete aggregate on the concrete strength

Fine Recycled Concrete Aggregate (FRCA) is one of the construction waste can be recycled. It can be the aggregate to replace the natural aggregate in concrete since we know the physical properties of materials are hard and strong. Demand for sand in the concrete production has been increased which become the problems in the concrete industry. This work deals with the effect of concrete incorporating with FRCA as partial replacement of sand. The percentage of natural sand replaced by the FRCA was 0%, 15%, 20%, 25%, 30%, 45% and 60%. Other than that, water cement ratio was manipulated variable started form 0.40, 0.45, 0.50, 0.55 and 0.60. In short, 20% replacement was the most suitable interaction of FRCA in the concrete occur that contribute to increasing in compressive strength. The porosity properties of FRCA been neutralized on that replacement percentage by the present of optimum filler effect generated form the very fine FRCA particle during the mixing process. Meanwhile, 0.50 water cement ratio was optimum condition for cement hydration process using FRCA as partial sand replacement

Behavior of fire exposed concrete-filled double skin steel tubular (CFDST) columns under concentric axial loads

This paper presents the result of an experimental investigation of axial behavior of concrete-filled double skin steel tubular (CFDST) columns exposed to high temperature under the action of monotonically applied concentric axial loads. The columns were exposed to ASTM E-119 standard fire curve until 600°C and kept constant for two different exposure time (i.e., 60 and 90 minutes). Failure patterns and reduction in strength, ductility and stiffness of CFDST columns are reported. Factors influencing the strength, ductility and stiffness of CFDST columns during fire exposure, i.e., exposure time, temperature of concrete core and temperature of inner steel tube, are also discusse

Splitting tensile and pullout behavior of synthetic wastes as fiber-reinforced concrete

Plastic bottles and waste wires are the most commonly discarded synthetic wastes that contribute to environmental pollution. Polyethylene terephthalate (PET) bottles act as one of the contributors to environmental pollution. One solution to environmental pollution includes recycling plastic bottle wastes as synthetic fibers and incorporating them into concrete. Therefore, pullout strengths of synthetic fibers in a concrete matrix should be investigated by conducting splitting tensile and pullout tests. Experiments of the present study used fibers from ring-shaped PET bottles with widths of 5 and 10 mm. Irregularly shaped PET bottles with 10–15 mm size, waste wires measuring 55 mm in length, and manufactured synthetic macro-fibers were also used in comparative analysis. Results indicate that an increase in fiber volume improves tensile strength of concrete. Incorporation of high-volume fiber with concrete results in a substantial amount of fibers bridging and crossing fractured sections, thereby activating failure resistance mechanisms. In comparison with irregularly shaped PET and waste wire fibers, ring-shaped fibers performed better as they are mainly designed to activate fiber yielding instead of fiber pullout. The load energy required to debond fibers and the concrete matrix was high when the surface contact area was large in comparison with that when a small surface contact area was considered. Fibers with small surface contact area easily slip under tensile stress. Thus, the surface contact area of fibers with concrete matrix allows good frictional resistance against pullout or tensile loa

Strength and physical properties of concrete brick at elevated temperature

This paper discusses the strength and physical properties of lightweight concrete brick before and after being exposed to fire. For this study, lightweight concrete brick was made up of cement, sand, expanded polystyrene (EPS) and palm oil fuel ash (POFA). EPS and POFA are replacement materials used as sand and cement replacement respectively. The percentage of replacement materials was varied, which 0%, 20%, 30%, 40% and 50% for EPS and 0%, 10% and 25% for POFA. The strength and physical properties of bricks were observed and tested before and after being exposed to elevated temperature. Fire performance test of bricks was tested using electronic furnace where the temperature of fire was 300oC, 500oC and 700oC with heating rate 10oC/min. The duration of fire test was conducted for 2 hours. Among the physical properties that have been observed are deformation of shape, discolouration and surface cracking of brick samples. Generally, the brick strength were decreased as the percentage of materials replacement increase. The reduction of strength was continued when bricks were exposed to high temperature. However, the strength of the bricks was fluctuated when been exposed to different temperature

MPEG-4 video transmission using distributed TDMA MAC protocol over IEEE 802.15.4 wireless technology

The issues of green technology nowadays give an inspiration to the researcher to make all the future design to be energy efficient. Medium Access Control (MAC) layer is the most effective layer to provide energy efficient due to its ability to control the physical radio directly. One of the important applications in the future is a video transmission that can be transmitted with low-cost and low power consumption. MPEG-4 is one of the international standards for moving video. MPEG-4 provide better compression and primarily design at low bit rate communication. In order to achieve good quality for video application, the design at MAC layer must be strong. Therefore, to increase the performance of the MPEG-4 in IEEE 802.15.4, in this paper we propose a cross layer design between MAC layer and Application layer. A priority queue will be implemented at MAC scheduling depends on the level of frame important in MPEG-4 format frame. A distributed Time division Multiple Access (TDMA) will be used for MAC protocol to provide reliable data transmission for high priority frame

Effect of Water to Cement Ratio and Replacement Percentage of Recycled Concrete Aggregate on the Concrete Strength

Fine Recycled Concrete Aggregate (FRCA) is one of the construction waste can be recycled. It can be the aggregate to replace the natural aggregate in concrete since we know the physical properties of materials are hard and strong. Demand for sand in the concrete production has been increased which become the problems in the concrete industry. This work deals with the effect of concrete incorporating with FRCA as partial replacement of sand. The percentage of natural sand replaced by the FRCA was 0%, 15%, 20%, 25%, 30%, 45% and 60%. Other than that, water cement ratio was manipulated variable started form 0.40, 0.45, 0.50, 0.55 and 0.60. In short, 20% replacement was the most suitable interaction of FRCA in the concrete occur that contribute to increasing in compressive strength. The porosity properties of FRCA been neutralized on that replacement percentage by the present of optimum filler effect generated form the very fine FRCA particle during the mixing process. Meanwhile, 0.50 water cement ratio was optimum condition for cement hydration process using FRCA as partial sand replacement

The adhesion GPCR Adgrg6 (Gpr126): Insights from the zebrafish model

Adhesion GPCRs are important regulators of conserved developmental processes and represent an untapped pool of potential targets for drug discovery. The adhesion GPCR Adgrg6 (Gpr126) has critical developmental roles in Schwann cell maturation and inner ear morphogenesis in the zebrafish embryo. Mutations in the human ADGRG6 gene can result in severe deficits in peripheral myelination, and variants have been associated with many other disease conditions. Here, we review work on the zebrafish Adgrg6 signaling pathway and its potential as a disease model. Recent advances have been made in the analysis of the structure of the Adgrg6 receptor, demonstrating alternative structural conformations and the presence of a conserved calcium‐binding site within the CUB domain of the extracellular region that is critical for receptor function. Homozygous zebrafish adgrg6 hypomorphic mutants have been used successfully as a whole‐animal screening platform, identifying candidate molecules that can influence signaling activity and rescue mutant phenotypes. These compounds offer promise for further development as small molecule modulators of Adgrg6 pathway activity

Mechanical properties of concrete containing untreated palm oil fuel ash and egg shell powder

This study aims to use two (2) waste products, namely Palm Oil Fuel Ash (POFA) and Egg Shell Powder (ESP) as cement replacement in concrete. This is because the properties of POFA and ESP are similar to the properties of cement. The objective of this study is to determine the mechanical properties (compressive strength and tensile strength) of concrete containing POFA and ESP as cement replacement. With both properties known, the optimum percentage of POFA and ESP as cement replacement can then be determined. The percentage of replacement of POFA was fixed at 20%, however the percentages of ESP varied from 0 to 20%. Six 100 � 100 � 100 mm cubes and six 100 � 200 mm cylinders were prepared for each variation of percentages. The cubes and cylinders were tested for compressive and tensile strength after 7 and 28 days of water curing. Generally, as the percentages of ESP increased, the workability, compressive strength and tensile strength of the concrete sample decreased. In conclusion, the combination of POFA and ESP as cement replacement in concrete is only able to achieved 76% of targeted strength

Review of coal bottom ash and coconut shell in the production of concrete

Concrete is the main construction material in the worldwide construction industry. High demand of sand in the concrete production have been increased which become the problems in industry. Natural sand is the most common material used in the construction industry as natural fine aggregate and it caused the availability of good quality of natural sand keep decreasing. The need for a sustainable and green construction building material is required in the construction industry. Hence, this paper presents utilization of coal bottom ash and coconut shell as partial sand replacement in production of concrete. It is able to save cost and energy other than protecting the environment. In summary, 30% usage of coal bottom ash and 25% replacement of coconut shell as aggregate replacement show the acceptable and satisfactory strength of concrete