Cracking behaviour of coal ash concrete based on acoustic emission technique

The continual rise of the power sector has resulted in massive production of coal waste by-products known as coal bottom ash (CBA) and fly ash (FA), which are formed when raw coal is burned to generate electricity. The disposal of CBA and FA contributes significantly to major environmental hazards and thereby extensive efforts are required to utilize these wastes. Recently, CBA in concrete has been successfully investigated in terms of microstructure, durability, and other common properties. However, it is non-trivial to remark that a topic that received less exploration is serviceability of structural performance, and the main concern being whether CBA aggregate affects the cracking of structural concrete due to the cyclic load. The crack identification is critically important because it gives the first sign of serious trouble indicating the load-carrying capacity and deficiencies in strength of structural elements. Therefore, this research aims to investigate the mechanical properties of plain concrete and cracking behaviour of reinforced concrete (RC) beam with inclusion of CBA. Thus, specimens were designed into four distinct combination replacements between half (50%) and full (100%) of coarse aggregate and fine aggregate using CBA with addition of 20% FA to the cement amount. The fresh concrete was tested by workability test while plain concrete specimens were made for compressive test, splitting tensile test and flexural tests to investigate the mechanical properties of concrete. Then RC beam specimens were cast for a 4-point bending test subjected to a cyclic load method to evaluate cracking behaviour. The assessment of the RC beam also used the acoustic emission (AE) technique that worked purposely for non-destructive testing (NDT). The experimental result shows that compressive strength of concrete for all replacements achieves targeted strength of 30 MPa at 28 days. However, splitting tensile and flexural strength decreased slightly when increasing the volume of CBA in the design mixture. Furthermore, the cyclic load criteria with respect to deviation from linearity (DFL) is promising to correlate to RC beam failure according to deflection in each specific load cycle. Nonetheless, the cracking behaviour of RC beams was mainly influenced by porous and high crushing index of coarse CBA and all tested RC beams failed to the flexural and shear crack failure. In AE parameter-based analysis, the correlation between average frequency and RA (rise time/amplitude) value shows that nucleation of cracks in early cycles are always recorded as a tensile mode with a high average frequency. Then, the crack switches to shear mode containing a high RA value at a subsequent cycle until ultimate load. The AE findings are well matched and consistent with the real visual inspection of crack damage that appeared on the RC beam surface during the experimental work in a laboratory. Thus, the obtained finding in this study indicates that the crack identification from AE technique is effective for structural monitoring, so it could benefit understanding the properties of CBA on the performance of concrete structures. Finally, the excessive usage of CBA in concrete contribute to large numbers of crack while producing wide crack width, but the utilization of CBA as a 50% gravel replacement has good structural performance under cyclic load test as they are comparable to the control RC beam

Experimental Validation of Reinforced Concrete Beam Incorporating Coal Fly Ash and Coal Bottom Ash Using Numerical Analysis

The environmental deterioration affected by the disposal of Coal Bottom Ash (CBA) from power stations has worsened as the energy demand has increased. In addition, the increased demand for concrete leads to an increase in aggregate consumption, which contributing to the depletion of natural resources. To prevent the immense amount of CBA waste and the destruction of natural resources, an initiative has been implemented to replace aggregate with CBA in concrete. The Reinforced Concrete (RC) beams underwent a four-point bending test. The test was done after 28 days of curing age. Therefore, this study was conducted to study the performance of RC beam incorporating CBA as fine and coarse aggregate replacement.  The deflection, maximum load and cracking pattern of RC beam were determined. Beam with 100% coarse coal bottom ash 100% fine coal bottom ash resulted to the maximum load at 88 kN with maximum deflection at 18.87 mm. The RC beams were redesigned using the three-dimensional nonlinear simulation software ABAQUS in enable to identify and compare the simulation and experimental findings. The FEA result shows that ultimate load of FEA was within 5% range with the experimental results. The simulation results demonstrated that the proposed finite element model accurately predicted the RC beam’s damage behaviour

Experimental Validation of Reinforced Concrete Beam Incorporating Coal Fly Ash and Coal Bottom Ash Using Numerical Analysis

The environmental deterioration affected by the disposal of Coal Bottom Ash (CBA) from power stations has worsened as the energy demand has increased. In addition, the increased demand for concrete leads to an increase in aggregate consumption, which contributing to the depletion of natural resources. To prevent the immense amount of CBA waste and the destruction of natural resources, an initiative has been implemented to replace aggregate with CBA in concrete. The Reinforced Concrete (RC) beams underwent a four-point bending test. The test was done after 28 days of curing age. Therefore, this study was conducted to study the performance of RC beam incorporating CBA as fine and coarse aggregate replacement.  The deflection, maximum load and cracking pattern of RC beam were determined. Beam with 100% coarse coal bottom ash 100% fine coal bottom ash resulted to the maximum load at 88 kN with maximum deflection at 18.87 mm. The RC beams were redesigned using the three-dimensional nonlinear simulation software ABAQUS in enable to identify and compare the simulation and experimental findings. The FEA result shows that ultimate load of FEA was within 5% range with the experimental results. The simulation results demonstrated that the proposed finite element model accurately predicted the RC beam’s damage behaviour

A review: Utilization of waste materials in concrete

Concrete is the most important material in building construction. It had been used widely around the world and is made of cement, fine aggregates, coarse aggregates and water. These materials come from natural resources which had a depletion and environmental pollution issues. On the other hand, tonnes of waste are generated around the world especially in developed country which are having rapid industrialization, increasing population growth, technological developments and urbanization. Most of the waste materials from those causes are not recyclable. The methods managing of the waste materials are usually done by dumping in landfills or burning. Thus, in order to overcome both issues, alternative replacements from waste materials can massively give huge differences to the industry that will reduce the usage of natural resources and gives benefits to the industry itself and also to the environment. Studies on waste materials had been conducted by many researchers before. Hence, in this paper, some materials which are coal bottom ash, slag, ceramic waste and glass powder will be discuss as waste materials that have been used from many backgrounds of industries. This paper attempt to summarize the investigation of the following materials as substitution materials in concrete, with the following discussion. The properties such as workability, compressive strength, ductility etc. of these replacement materials are compared with the normal concrete. A lightweight concrete that is safe and eco-friendly will be produced as a construction material. This shows that some of the materials can improve the performance of concrete itself. Thus, this study is crucial in finding the other waste materials that can act as a replacement

Experimental Validation of Reinforced Concrete Beam Incorporating Coal Fly Ash and Coal Bottom Ash Using Numerical Analysis

The environmental deterioration affected by the disposal of Coal Bottom Ash (CBA) from power stations has worsened as the energy demand has increased. In addition, the increased demand for concrete leads to an increase in aggregate consumption, which contributing to the depletion of natural resources. To prevent the immense amount of CBA waste and the destruction of natural resources, an initiative has been implemented to replace aggregate with CBA in concrete. The Reinforced Concrete (RC) beams underwent a four-pointbending test. The test was done after 28 days of curingage. Therefore, this study was conducted to study the performance of RC beam incorporating CBA as fine and coarse aggregate replacement. The deflection, maximum load and cracking pattern of RC beam were determined. Beam with 100% coarse coal bottom ash 100% fine coal bottom ash resulted to the maximum load at 88 kN with maximum deflection at 18.87 mm. The RC beams were redesigned using the three-dimensional nonlinear simulation software ABAQUS in enable to identify and compare the simulation and experimental findings. The FEA result shows that ultimate load of FEA waswithin 5% range with the experimental results. The simulation results demonstrated that the proposed finite element model accurately predicted the RC beam’s damage behaviour

Structural performance of beam using high volume bottom ash as fine and coarse aggregate replacement

Coal fired power plant produces abundance of by-product in the form of bottom ash and fly ash that can be categorized as a waste which threatens environment as well as health and safety of human life. Every year, large number of coal fire plant wastes is disposed and this put pressure to disposal site as the site could almost reach its design capacity. Hence, innovative and sustainable solutions may require to reduce the amount of waste such as reusing the waste as construction materials for infrastructure development. This paper discuss, the coal bottom ash (CBA) used as fine and coarse aggregate replacement in reinforcement concrete (RC) beams. The RC beams with CBA were tested under four point bending test to investigate the behaviour of the RC beams under bending. The deflection and applied load was recorded while the cracking pattern was observed and marked to evaluate the behaviour and the performance of RC beams. The results show that the performance of RC beam with CBA replacement was comparable with the normal RC beam as the crack pattern and applied load was almost the same

Behavior on the mechanical performance and scanning electron microscopy of coal waste brick

Waste is a common ingredient in Malaysia that has to do with man-made waste. Waste materials can be abundant in landfills without any profit. Waste materials can be harmful to the environment as well as to human health. One of the most abundant wastes is coal combustion ash from coal-fired power plants. In addition, the most common material used in the construction industry is brick. Bricks have been used for non-polluting structures and must be made of durable materials. The common material used for bricks is clay, sand and cement. All these ingredients are derived from natural resources. The depletion of natural resources has been a cause of concern for many. Therefore, this paper focuses on the development of bricks from coal terms of mechanical properties. The density, compressive strength and water absorption capacity of bricks made from coal ash were investigated after curing for 7, 14 and 28 days. The results show that the density of bricks made from coal ash is low, while the compressive strength meets the requirements and is 10.25 MPa and 8.67 MPa higher than control concrete, respectively. For the crushing value, the coal ash was compared with the coarse aggregate to meet the requirements of the test. The result shows that the coal is 34.6% higher than the natural aggregate. In conclusion, the use of coal ash in the production of bricks is a promising long-term option for the production of bricks

Review of mechanical performance of oil palm fiber and coconut fiber as an additional material in concrete

Waste can be categorized as organic waste and chemical waste. Organic waste generated from agriculture industry had been proofed to be use in concrete production to enhance the concrete performance. The main purpose of adding the fiber in concrete structure is to control cracking due to plastic shrinkage and to drying shrinkage. Besides, it can also reduce the permeability of concrete, thus, reduce the bleeding of water. Some types of fibers produce greater impact, abrasion, and shatter resistance in concrete. Therefore, this paper reviewed the mechanical properties of concrete containing oil palm and coconut fiber as an additional material in concrete. Coconut fiber length is longer than oil palm fiber. Therefore, in comparison, by adding coconut fiber in concrete up to 5% may reduce the flexural and tensile strength of the concrete due to agglomerate effect of the fiber. In contrast, for oil palm fiber, beyond 5% of addition in concrete will improve the flexural and tensile strength of the concrete due to the length effect of the fiber. By discussing both organic fiber as an additional material to strengthen the concrete, it can contribute to the body of knowledge in term of reducing cracks in concrete. Besides, it will give a better understanding to readers regarding the function of the materials in concrete

Coal bottom ash concrete: Mechanical properties and cracking mechanism of concrete subjected to cyclic load test

Coal waste has gained interest as an alternative aggregate for concrete production. Still, a topic that has been less researched is the serviceability of concrete containing coal waste, and the main concern is whether the namely coal bottom ash (CBA) aggregate affects the cracking of concrete beams. This research aims to elucidate the mechanical properties of concrete with the inclusion of CBA and its cracking mechanism on beams. Thus, concrete specimens were designed into four distinct combination replacements between half (50 %) and full (100 %) of coarse and fine CBA aggregate with the addition of 20 % fly ash to the cement amount. The beams were subjected to a cyclic load test to evaluate the cracking mechanism. The experimental results revealed that the compressive strength of all replacements achieved the targeted strength of 30 MPa at 28 days. However, the splitting tensile and flexural strengths decreased with the increment in volume of CBA in the design mixture. The cyclic load criteria with respect to deviation from linearity (DFL) was found promising to correlate to beam failure according to the deflection in each specific load cycle. Nonetheless, the cracking mechanism of the concrete beams was mainly influenced by the porous structure and high crushing index of coarse CBA, where all tested beams failed by flexural and shear cracks. Therefore, excessively increasing the coarse CBA replacement amount in a concrete mix produces a lower structural performance in beams under cyclic load

Coal bottom ash lightweight brick

100% and 50% replacement with coal ash. Reduce 40% of production cost. 20% less dense compare conventional brick