The construction industry has seen a growing emphasis on the use of sustainable materials in rece... more The construction industry has seen a growing emphasis on the use of sustainable materials in recent years. This is driven by various factors, including a desire to reduce environmental impact, improve indoor air quality, and promote the health and well-being of building occupants. One sustainable material that is being increasingly utilized in construction is natural fibers. Phragmites australis fibers, in particular, are renewable, biodegradable, and have a low carbon footprint. The present study aims to evaluate the impact of Phragmites australis fibers on the behavior of reinforced concrete beams. Five concrete mixes were utilized in the experiment, with the control mix having a 1:1.5:3 ratio of cement to sand to coarse aggregate by weight. The other four mixes incorporated Phragmites australis fibers at 0%, 0.5%, 1%, and 1.5% of the volume of the mix, with cement replaced by 10% glass by weight. The water-to-cement ratio was set at 0.4 for all mixes. Concrete cubes, cylinders, a...
Corrosion of reinforcing steel is the one of the main causes of deterioration in reinforced concr... more Corrosion of reinforcing steel is the one of the main causes of deterioration in reinforced concrete structure. During the initial stage of corrosion, the steel volume increases. This creates tensile stresses in the concrete, which can eventually lead to cracking, delamination, and spalling. This potential risk of corrosion in a structure is quite unpredictable. Therefore, this paper examines the influence of accelerated corrosion on the bond between concrete and the coated and uncoated steel bars. The bar coating consisted of epoxy rich in zinc. Six concrete mixes were prepared. Three mixes had cement contents of 300, 400 and 500 Kg/m3 and a water cement ratio of 0.4. In the rest of the mixes, cement was replaced with 10% silica fume and the water to binder ratio was 0.5. The reinforcing bars were placed inside concrete cylinders. After curing for 3 days, the specimens were immersed in a 5% NaCl solution for 7 days while a DC current of 5V flowed through them using a portable power...
The improper curing of concrete can seriously affect its hardened properties. However, a large qu... more The improper curing of concrete can seriously affect its hardened properties. However, a large quantity of water is required to cure concrete after casting. Water is a valuable resource and its availability is posing a particular challenge in the Middle East including the Kurdistan region of Iraq. Self-curing concrete may be considered a novel curing method in that the water inside the concrete mix is retained so that hydration can continue without the supply of additional water after casting. Therefore, the aim of this study was to include a self-curing agent, named Polyethylene glycol-400 (PEG-400), as one of the concrete mix constituents in order to save water that is normally required after casting. Six concrete mixes were cast with a constant W/C ratio of 0.5; two of them were ordinary concrete mixes whereas the other mixes contained 0.5%, 1%, 1.5%, and 2% of PEG-400 by weight of cement. All concrete ingredients, except the PEG-400, were provided locally. Three different curing...
Nowadays, the increasing demand for concrete is causing serious environmental impact including po... more Nowadays, the increasing demand for concrete is causing serious environmental impact including pollution and waste generation, rapid depletion of natural resources, and increased CO2 emission. Incorporating natural fibers in concrete can contribute toward environmental sustainability. This paper is concerned with the use of natural fibers obtained from the plant species Phragmites australis (PA). The plant is invasive, and rapidly grows abundantly along rivers and waterways, causing major ecological problems. This research is part of a wide range investigation on the use of natural fibers produced from the stem of PA plants in concrete. Using a machine, plant stems were crushed into fibers measuring 40 mm in length and 2 mm in width, and treated with 4% NaOH solution for 24 h. A total of four concrete mixes were prepared with varying additions of treated fibers, ranging from 0% to 1.5% (by volume) with water to cement ratio of 0.5% (by volume). Concrete specimens were tested at 3, 7...
Numerous studies investigated the possibility of incorporating plastic wastes in concrete mixture... more Numerous studies investigated the possibility of incorporating plastic wastes in concrete mixtures, thus contributing to efficient management and sustainable development of the construction industry. This paper investigates the possibility of reducing the water-to-cement ratio and/or incorporating steel fibers or polymeric latexes to mitigate the drop in structural properties of reinforced concrete (RC) beams containing polyethylene terephthalate (PET) additions. The PET was derived from waste plastic bottles that were shredded into small pieces and added during concrete batching at 1.5% to 4.5%, by total volume. Test results showed that the concrete plain and structural properties degrade with PET additions, given their lightweight nature and poor characteristic strength compared to aggregate particles. The reduction of w/c from 0.55 to 0.46 proved efficient to refine the matrix porosity and reinstate the shear and flexural strengths of RC beams. Moreso, the incorporation of 0.8% s...
The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss ... more The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss of water and chemical reactions. Incorporating limestone fines (LF) as a cement replacement can affect the shrinkage of the paste. To examine this effect, five paste mixes were prepared with 0, 5, 10, 15 and 20% LF as a cement replacement and with a water-to-binder ratio (w/b) of 0.45. Four volume stability tests were conducted for each paste: chemical, autogenous and drying shrinkage and expansion. Chemical shrinkage was tested each hour for the first 24 h and thereafter every 2 days for a total period of 90 days. The drying shrinkage, autogenous shrinkage and expansion were monitored every 2 days until 90 days. The results showed that replacing 15% LF enhanced the chemical shrinkage of the paste. However, autogenous shrinkage of the paste was found to increase between 0 and 10% LF and decline sharply at 15 and 20% LF. Drying shrinkage was found to increase with the increase in LF conte...
The effect of palm fibers on the absorption and mechanical properties of hardened concrete is pre... more The effect of palm fibers on the absorption and mechanical properties of hardened concrete is presented in this paper. To achieve this aim, four concrete mixes were prepared with varying amount of fibers. The volume of fiber in the mix is 0%, 0.5%, 1% and 1.5%. The water to cement ratio for all mixes is kept constant. Five tests were performed for each concrete mixtures: ultrasonic pulse velocity, compressive strength, density, sorptivity and total water absorption. Concrete were cured for 3, 7, 28 and 90 days. Results indicated that acceptable concrete quality can be achieved with the addition of palm fibers. On the other side, the inclusion of palm fibers reduces the compressive strength up to 30% on average and the density by 4% as the percentage of fibers increases from 0% to 1.5%. In addition, the capillary water absorption coefficient and total absorption increase with the increase of palm fibers but decreases significantly with curing durations.
The objectives of this research is to investigate the influence of Municipal Solid Waste Incinera... more The objectives of this research is to investigate the influence of Municipal Solid Waste Incinerated Bottom Ashes (MSWI-BA) on engineering properties of specimens when part of fine aggregate is replaced with it. Disposal of municipal wastes is a major key issue which causes a problematic challenge in Lebanon as landfill space for the disposal of ash from Municipal Solid Waste Incineration (MSWI) becomes rare. It becomes smarter to reduce the volume of materials being disposed. Recycling is one approach, waste minimization is the second, and combustion for energy production is the third. Therefore, one of the possibilities that have a beneficial impact on the environment and consequently on the society is to use Municipal Solid Waste Incineration (MSWI) ashes in concrete production, as it is done with coal combustion products. The bottom ash features the most convenient composition for this purpose as it is available in highest amounts among the MSWI ashes. Bottom ash can be used as ...
This work is part of a wide ranging research project on the optimum use of waste from the dry and... more This work is part of a wide ranging research project on the optimum use of waste from the dry and semi dry flue gas desulphurisation (FGD) processes in concrete. It reports the resistance of mortars containing ground granulated blastfurnace slag (S) and a typical simulated desulphurised waste (SDW) to a magnesium sulphate solution. The binder consists of cement (C), S and SDW. The cement content was kept constant (10%) and then the slag was replaced with increasing levels of SDW. The mortar consists of 1 part binder to 3 parts sand and the water to binder ratio was 0.55. Samples were exposed to 2.44% magnesium sulphate solution. The samples containing cement-slag-simulated desulphurised waste (C-SSDW) were compared to a reference sample of 100% cement. All C-S-SDW mortars exhibited superior sulphate resistance compared to reference mortars. This was attributed to reduction in the reactive phases that contribute the sulphate attack. Increasing the SDW content in the C-S-SDW blend als...
The purpose of this research was to evaluate a kaolin clay obtained from local Lebanese source af... more The purpose of this research was to evaluate a kaolin clay obtained from local Lebanese source after being subjected to thermal treatment. A sample of kaolin clay was collected from local resources and subjected to a treatment process for enhancing its pozzolanic properties. The treated sample was characterized through testing procedure as per ASTM C311. It was found that the physical and chemical properties were in compliance with the relevant ASTM C618 standard. This indicates that the proposed treatment succeeded in developing and exhibiting the pozzolanic activity of the end product. The activity index test of the treated samples was investigated to verify the quality and performance of the end product which was found to be satisfactory. Therefore, the treated product is accepted to be classified as natural Pozzolan as per ASTM C618. The potential of producing Metakolin in Lebanon is of high importance due to its availability in large quantities. Moreover, it might be used to re...
Journal of Engineering, Design and Technology, 2021
Purpose The purpose of this paper is to concern with using municipal solid waste incineration bot... more Purpose The purpose of this paper is to concern with using municipal solid waste incineration bottom ash (MSWI-BA) in concrete application. Design/methodology/approach In this paper, the performance of reinforced concrete (RC) beams containing MSWI-BA was investigated. Four concrete mixes were used in this study. The control mix had a proportion of 1 (cement): 2 (fine aggregates): 4 (coarse aggregates) by weight. In the other three mixes, the fine aggregates were partially replaced with 20%, 40% and 60% MSWI-BA (by weight). The water to cement ratio was kept constant at 0.5 in all mixes. Concrete cubes and cylinders were prepared to determine some physical and mechanical properties of concrete, whereas RC beams were used for determining the structural performance. Findings There was an increase in compressive strength, tensile strength and the modulus of elasticity when 20% of fine aggregates were replaced with MSWI-BA. However, beyond 20% these properties were reduced. The load bea...
The construction industry has seen a growing emphasis on the use of sustainable materials in rece... more The construction industry has seen a growing emphasis on the use of sustainable materials in recent years. This is driven by various factors, including a desire to reduce environmental impact, improve indoor air quality, and promote the health and well-being of building occupants. One sustainable material that is being increasingly utilized in construction is natural fibers. Phragmites australis fibers, in particular, are renewable, biodegradable, and have a low carbon footprint. The present study aims to evaluate the impact of Phragmites australis fibers on the behavior of reinforced concrete beams. Five concrete mixes were utilized in the experiment, with the control mix having a 1:1.5:3 ratio of cement to sand to coarse aggregate by weight. The other four mixes incorporated Phragmites australis fibers at 0%, 0.5%, 1%, and 1.5% of the volume of the mix, with cement replaced by 10% glass by weight. The water-to-cement ratio was set at 0.4 for all mixes. Concrete cubes, cylinders, a...
Corrosion of reinforcing steel is the one of the main causes of deterioration in reinforced concr... more Corrosion of reinforcing steel is the one of the main causes of deterioration in reinforced concrete structure. During the initial stage of corrosion, the steel volume increases. This creates tensile stresses in the concrete, which can eventually lead to cracking, delamination, and spalling. This potential risk of corrosion in a structure is quite unpredictable. Therefore, this paper examines the influence of accelerated corrosion on the bond between concrete and the coated and uncoated steel bars. The bar coating consisted of epoxy rich in zinc. Six concrete mixes were prepared. Three mixes had cement contents of 300, 400 and 500 Kg/m3 and a water cement ratio of 0.4. In the rest of the mixes, cement was replaced with 10% silica fume and the water to binder ratio was 0.5. The reinforcing bars were placed inside concrete cylinders. After curing for 3 days, the specimens were immersed in a 5% NaCl solution for 7 days while a DC current of 5V flowed through them using a portable power...
The improper curing of concrete can seriously affect its hardened properties. However, a large qu... more The improper curing of concrete can seriously affect its hardened properties. However, a large quantity of water is required to cure concrete after casting. Water is a valuable resource and its availability is posing a particular challenge in the Middle East including the Kurdistan region of Iraq. Self-curing concrete may be considered a novel curing method in that the water inside the concrete mix is retained so that hydration can continue without the supply of additional water after casting. Therefore, the aim of this study was to include a self-curing agent, named Polyethylene glycol-400 (PEG-400), as one of the concrete mix constituents in order to save water that is normally required after casting. Six concrete mixes were cast with a constant W/C ratio of 0.5; two of them were ordinary concrete mixes whereas the other mixes contained 0.5%, 1%, 1.5%, and 2% of PEG-400 by weight of cement. All concrete ingredients, except the PEG-400, were provided locally. Three different curing...
Nowadays, the increasing demand for concrete is causing serious environmental impact including po... more Nowadays, the increasing demand for concrete is causing serious environmental impact including pollution and waste generation, rapid depletion of natural resources, and increased CO2 emission. Incorporating natural fibers in concrete can contribute toward environmental sustainability. This paper is concerned with the use of natural fibers obtained from the plant species Phragmites australis (PA). The plant is invasive, and rapidly grows abundantly along rivers and waterways, causing major ecological problems. This research is part of a wide range investigation on the use of natural fibers produced from the stem of PA plants in concrete. Using a machine, plant stems were crushed into fibers measuring 40 mm in length and 2 mm in width, and treated with 4% NaOH solution for 24 h. A total of four concrete mixes were prepared with varying additions of treated fibers, ranging from 0% to 1.5% (by volume) with water to cement ratio of 0.5% (by volume). Concrete specimens were tested at 3, 7...
Numerous studies investigated the possibility of incorporating plastic wastes in concrete mixture... more Numerous studies investigated the possibility of incorporating plastic wastes in concrete mixtures, thus contributing to efficient management and sustainable development of the construction industry. This paper investigates the possibility of reducing the water-to-cement ratio and/or incorporating steel fibers or polymeric latexes to mitigate the drop in structural properties of reinforced concrete (RC) beams containing polyethylene terephthalate (PET) additions. The PET was derived from waste plastic bottles that were shredded into small pieces and added during concrete batching at 1.5% to 4.5%, by total volume. Test results showed that the concrete plain and structural properties degrade with PET additions, given their lightweight nature and poor characteristic strength compared to aggregate particles. The reduction of w/c from 0.55 to 0.46 proved efficient to refine the matrix porosity and reinstate the shear and flexural strengths of RC beams. Moreso, the incorporation of 0.8% s...
The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss ... more The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss of water and chemical reactions. Incorporating limestone fines (LF) as a cement replacement can affect the shrinkage of the paste. To examine this effect, five paste mixes were prepared with 0, 5, 10, 15 and 20% LF as a cement replacement and with a water-to-binder ratio (w/b) of 0.45. Four volume stability tests were conducted for each paste: chemical, autogenous and drying shrinkage and expansion. Chemical shrinkage was tested each hour for the first 24 h and thereafter every 2 days for a total period of 90 days. The drying shrinkage, autogenous shrinkage and expansion were monitored every 2 days until 90 days. The results showed that replacing 15% LF enhanced the chemical shrinkage of the paste. However, autogenous shrinkage of the paste was found to increase between 0 and 10% LF and decline sharply at 15 and 20% LF. Drying shrinkage was found to increase with the increase in LF conte...
The effect of palm fibers on the absorption and mechanical properties of hardened concrete is pre... more The effect of palm fibers on the absorption and mechanical properties of hardened concrete is presented in this paper. To achieve this aim, four concrete mixes were prepared with varying amount of fibers. The volume of fiber in the mix is 0%, 0.5%, 1% and 1.5%. The water to cement ratio for all mixes is kept constant. Five tests were performed for each concrete mixtures: ultrasonic pulse velocity, compressive strength, density, sorptivity and total water absorption. Concrete were cured for 3, 7, 28 and 90 days. Results indicated that acceptable concrete quality can be achieved with the addition of palm fibers. On the other side, the inclusion of palm fibers reduces the compressive strength up to 30% on average and the density by 4% as the percentage of fibers increases from 0% to 1.5%. In addition, the capillary water absorption coefficient and total absorption increase with the increase of palm fibers but decreases significantly with curing durations.
The objectives of this research is to investigate the influence of Municipal Solid Waste Incinera... more The objectives of this research is to investigate the influence of Municipal Solid Waste Incinerated Bottom Ashes (MSWI-BA) on engineering properties of specimens when part of fine aggregate is replaced with it. Disposal of municipal wastes is a major key issue which causes a problematic challenge in Lebanon as landfill space for the disposal of ash from Municipal Solid Waste Incineration (MSWI) becomes rare. It becomes smarter to reduce the volume of materials being disposed. Recycling is one approach, waste minimization is the second, and combustion for energy production is the third. Therefore, one of the possibilities that have a beneficial impact on the environment and consequently on the society is to use Municipal Solid Waste Incineration (MSWI) ashes in concrete production, as it is done with coal combustion products. The bottom ash features the most convenient composition for this purpose as it is available in highest amounts among the MSWI ashes. Bottom ash can be used as ...
This work is part of a wide ranging research project on the optimum use of waste from the dry and... more This work is part of a wide ranging research project on the optimum use of waste from the dry and semi dry flue gas desulphurisation (FGD) processes in concrete. It reports the resistance of mortars containing ground granulated blastfurnace slag (S) and a typical simulated desulphurised waste (SDW) to a magnesium sulphate solution. The binder consists of cement (C), S and SDW. The cement content was kept constant (10%) and then the slag was replaced with increasing levels of SDW. The mortar consists of 1 part binder to 3 parts sand and the water to binder ratio was 0.55. Samples were exposed to 2.44% magnesium sulphate solution. The samples containing cement-slag-simulated desulphurised waste (C-SSDW) were compared to a reference sample of 100% cement. All C-S-SDW mortars exhibited superior sulphate resistance compared to reference mortars. This was attributed to reduction in the reactive phases that contribute the sulphate attack. Increasing the SDW content in the C-S-SDW blend als...
The purpose of this research was to evaluate a kaolin clay obtained from local Lebanese source af... more The purpose of this research was to evaluate a kaolin clay obtained from local Lebanese source after being subjected to thermal treatment. A sample of kaolin clay was collected from local resources and subjected to a treatment process for enhancing its pozzolanic properties. The treated sample was characterized through testing procedure as per ASTM C311. It was found that the physical and chemical properties were in compliance with the relevant ASTM C618 standard. This indicates that the proposed treatment succeeded in developing and exhibiting the pozzolanic activity of the end product. The activity index test of the treated samples was investigated to verify the quality and performance of the end product which was found to be satisfactory. Therefore, the treated product is accepted to be classified as natural Pozzolan as per ASTM C618. The potential of producing Metakolin in Lebanon is of high importance due to its availability in large quantities. Moreover, it might be used to re...
Journal of Engineering, Design and Technology, 2021
Purpose The purpose of this paper is to concern with using municipal solid waste incineration bot... more Purpose The purpose of this paper is to concern with using municipal solid waste incineration bottom ash (MSWI-BA) in concrete application. Design/methodology/approach In this paper, the performance of reinforced concrete (RC) beams containing MSWI-BA was investigated. Four concrete mixes were used in this study. The control mix had a proportion of 1 (cement): 2 (fine aggregates): 4 (coarse aggregates) by weight. In the other three mixes, the fine aggregates were partially replaced with 20%, 40% and 60% MSWI-BA (by weight). The water to cement ratio was kept constant at 0.5 in all mixes. Concrete cubes and cylinders were prepared to determine some physical and mechanical properties of concrete, whereas RC beams were used for determining the structural performance. Findings There was an increase in compressive strength, tensile strength and the modulus of elasticity when 20% of fine aggregates were replaced with MSWI-BA. However, beyond 20% these properties were reduced. The load bea...
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Papers by Jamal Khatib