Papers by HERSH H A M A A M I N F Mahmood
Emerging Technologies and Engineering Journal, 2024
Textile-reinforced mortar (TRM) or fabric-reinforced concrete has a wide range of applications, i... more Textile-reinforced mortar (TRM) or fabric-reinforced concrete has a wide range of applications, including repair work, structural strengthening, ditch lining, erosion control, pipe protection, trackways, flood defenses, roofing, and emergency helicopter landing pads. This paper focuses specifically on structural strengthening, particularly shear strengthening and jacketing. According to the findings, among the materials considered, benzobisoxazole (PBO) proves to be the most effective, enhancing the shear capacity of the members by 43.3%, followed by carbon, basalt, and glass fibers. When using fixed materials for strengthening, a U-shaped configuration is more effective than an S-shaped one, increasing shear capacity by 131% compared to 71% for the S-shape. The results also show that increasing the number of textile layers during the strengthening process boosts the shear capacity of the element. Applying the textile layers directly in a straight pattern provides higher capacity than a spiral application. Furthermore, using epoxy resin as a mortar for TRM results in a greater load capacity for column strengthening. A column strengthened with two layers of textiles had more capacity than one with just a single layer. Additionally, when the mortar contains a cementitious material modified with polymer, the flexural capacity is 5.3% higher than that of textiles using cement alone as the mortar.
Smart Green M aterials, 2024
Textile-reinforced mortar (TRM) or fabric-reinforced concrete has a wide range of applications, i... more Textile-reinforced mortar (TRM) or fabric-reinforced concrete has a wide range of applications, including repair work, structural strengthening, ditch lining, erosion control, pipe protection, trackways, flood defenses, roofing, and emergency helicopter landing pads. This paper focuses specifically on structural strengthening, particularly shear strengthening and jacketing. According to the findings, among the materials considered, benzobisoxazole (PBO) proves to be the most effective, enhancing the shear capacity of the members by 43.3%, followed by carbon, basalt, and glass fibers. When using fixed materials for strengthening, a U-shaped configuration is more effective than an S-shaped one, increasing shear capacity by 131% compared to 71% for the S-shape. The results also show that increasing the number of textile layers during the strengthening process boosts the shear capacity of the element. Applying the textile layers directly in a straight pattern provides higher capacity than a spiral application. Furthermore, using epoxy resin as a mortar for TRM results in a greater load capacity for column strengthening. A column strengthened with two layers of textiles had more capacity than one with just a single layer. Additionally, when the mortar contains a cementitious material modified with polymer, the flexural capacity is 5.3% higher than that of textiles using cement alone as the mortar.
Construction & building materials, Mar 1, 2024
مجلة جامعة دهوك, Dec 20, 2023
In today's world, all kind of materials are used to improve the materials used in project. Our re... more In today's world, all kind of materials are used to improve the materials used in project. Our research is about different mineral admixture on a type of concrete called roller compacted concrete (RCC), which has various uses in paving and dam construction. In this article, the effect of some mineral admixture on the mechanical properties and durability of roller compacted concrete has been investigated. Several mineral admixtures, such as metakaolin, fly ash, silica fume, ground granulated blast furnace slag, rice husk ash, palm oil fuel ash, and, either completely or partially replace cement. In this work, an attempts has been made to find out how adding these mineral admixtures can improve the performance of roller compacted concrete. The strength obtained varies based on the mineral admixtures produced by adding them to roller compacted concrete. The reviewed results of the work done have shown that 5-10% of silica fume, 15-20% of metakaolin, 10-15% of fly Ash, 10% of limestone, 5% of RHA and Coal waste powder, 15% of steel filing, 10% of (Bagasse Ash , natural pozzolan and Basalt rock flour), 15% of GGBS, 10% of POFA and Sugarcane ash, 2% of nano silica cement substitute has the best results on mechanical properties and durability of RCC.
Comprehensive Materials Processing, 2014
h i g h l i g h t s Isostatic graphite (IG) waste powder from the milling of molds for EDM, can b... more h i g h l i g h t s Isostatic graphite (IG) waste powder from the milling of molds for EDM, can be use as filler in advanced cement composites. Mechanical properties and thermal conductivity are increased with IG in cementitious composites. Carbonation of cementitious composites is increased with IG. IG-Cement Composite showed a sealed microstructure and close interphase by SEM analysis. IG used as addition can be new source for low-cost multifunctional cement-based materials.
Journal of University of Duhok, 2023
In today's world, all kind of materials are used to improve the materials used in project. Our re... more In today's world, all kind of materials are used to improve the materials used in project. Our research is about different mineral admixture on a type of concrete called roller compacted concrete (RCC), which has various uses in paving and dam construction. In this article, the effect of some mineral admixture on the mechanical properties and durability of roller compacted concrete has been investigated. Several mineral admixtures, such as metakaolin, fly ash, silica fume, ground granulated blast furnace slag, rice husk ash, palm oil fuel ash, and, either completely or partially replace cement. In this work, an attempts has been made to find out how adding these mineral admixtures can improve the performance of roller compacted concrete. The strength obtained varies based on the mineral admixtures produced by adding them to roller compacted concrete. The reviewed results of the work done have shown that 5-10% of silica fume, 15-20% of metakaolin, 10-15% of fly Ash, 10% of limestone, 5% of RHA and Coal waste powder, 15% of steel filing, 10% of (Bagasse Ash , natural pozzolan and Basalt rock flour), 15% of GGBS, 10% of POFA and Sugarcane ash, 2% of nano silica cement substitute has the best results on mechanical properties and durability of RCC.
Journal of studies in science and engineering, Dec 30, 2022
The thermal performance of a concrete roof between the main slab (concrete slab) and secondary sl... more The thermal performance of a concrete roof between the main slab (concrete slab) and secondary slab (gypsum board) has been investigated in this work with and without a ventilator. The hourly averaged climatic data (combined optical and thermal condition) of the external roof surface was used as the resource for the boundary conditions of Erbil city (Kurdistan Region, Iraq). The results of measuring the effects of using a ventilator between the concrete slabs and gypsum boards indicated that the moving air in the layer between slabs by using the ventilation process has more effect in cooling roofs and the room temperature had less than that of slabs that do not use ventilation, and so using baffle shape gypsum board as the secondary slabs for air turbulence to increase air velocity, the number of mass flow rates have more efficient in the cooling process and fast the cooling process, the surface temperature was reduced by (4.5oC and 3.6 oC) with the mass flow rates of (3.5kg/s) and (2kg/s) respectively, this is due to moving air makes roof slab cool and loss the heat that transfers through the slabs, so using this technique for an exciting roof is a good choice.
The Journal of University of Duhok
Journal of Studies in Science and Engineering, 2022
The thermal performance of a concrete roof between the main slab (concrete slab) and secondary sl... more The thermal performance of a concrete roof between the main slab (concrete slab) and secondary slab (gypsum board) has been investigated in this work with and without a ventilator. The hourly averaged climatic data (combined optical and thermal condition) of the external roof surface was used as the resource for the boundary conditions of Erbil city (Kurdistan Region, Iraq). The results of measuring the effects of using a ventilator between the concrete slabs and gypsum boards indicated that the moving air in the layer between slabs by using the ventilation process has more effect in cooling roofs and the room temperature had less than that of slabs that do not use ventilation, and so using baffle shape gypsum board as the secondary slabs for air turbulence to increase air velocity, the number of mass flow rates have more efficient in the cooling process and fast the cooling process, the surface temperature was reduced by (4.5oC and 3.6 oC) with the mass flow rates of (3.5kg/s) and (2kg/s) respectively, this is due to moving air makes roof slab cool and loss the heat that transfers through the slabs, so using this technique for an exciting roof is a good choice.
Journal of Studies in Science and Engineering, 2022
From the layout of a metallic structure`s beam-column connection w, while the seismic design is i... more From the layout of a metallic structure`s beam-column connection w, while the seismic design is inside the dissipative method, precise contributors and zones ought to admit the growth of plastic deformation, and many metallic second resisting frames fail on the beam-column joints. This examines designed a unique structural machine with diverse slit dampers to triumph over this challenge, which can be easier to deliver overall seismic performance in the structural device that has been proposed. Plastic deformation is confined to the slit dampers at the end flange, which is the machine's key characteristic. The recommended connection's seismic overall performance changed into confirmed the use of the Abaqus software program utility to software systems with diverse slit damper forms. The proposed hyperlink exhibited first-rate hysteretic conduct in accordance to check results. Furthermore, on this machine, strength dissipation and plastic deformation focus on the diverse shapes...
Journal of Studies in Science and Engineering
Nowadays, the performance criteria for concrete construction are moving toward eco-efficiency, wh... more Nowadays, the performance criteria for concrete construction are moving toward eco-efficiency, which is a method of producing highly durable and environmentally friendly concrete while minimizing both manufacturing costs and environmental load. Admixtures are commonly used in all concrete construction; however, some of them are harmful to human health and cause leaching, which is responsible for environmental pollution. On this principle, one of the eco-efficiency method's techniques is to use natural materials as additives in concrete. The paper continues to discuss the experi-mental data generated at the author's laboratory as part of exploratory work on the use of natural materials and their impact on the properties of cement, mortars, and concretes in terms of improving fresh, mechanical, and durability properties of concrete , The paper concludes that the observed impacts of using these natural material additions on the properties of mortar and concrete will motivate gr...
Journal of Studies in Science and Engineering, 2022
Nowadays, the performance criteria for concrete construction are moving toward eco-efficiency, a ... more Nowadays, the performance criteria for concrete construction are moving toward eco-efficiency, a method of producing highly durable and environmentally friendly concrete while minimizing both manufacturing costs and environmental load. Admixtures are commonly used in all concrete construction; however, some harm human health and cause leaching, which is responsible for environmental pollution. On this principle, one of the eco-efficiency method's techniques is to use natural materials as additives in concrete. The paper continues to discuss the experimental data generated at the author's laboratory as part of exploratory work on the use of natural materials and their impact on the properties of cement, mortars and concretes in terms of improving fresh, mechanical, and durability properties of concrete, The paper concludes that the observed impacts of using these natural material additions on the properties of mortar and concrete will motivate greater research in these areas, thereby improving the sustainability of concrete constructions.
case study in construction materials, 2022
In this experimental study, physical, strength and durability properties of roller compacted conc... more In this experimental study, physical, strength and durability properties of roller compacted concrete (RCC) containing metakaolin with or without steel fiber are investigated. For this purpose, seven different mixes were designed and tested in the lab. To assess properties of compressive strength, splitting tensile strength, water permeability and freezing and thawing resistance in terms of weight and compressive strength losses. There is an increasing compressive strength of RCC containing MK with or without steel fiber with increasing ages. 15% MK 45 kg/ m 3 steel fiber was found the best dosage for RCC at the age of 90 days. Also, there is a splitting tensile strength enhancement being increased with increasing MK and steel fiber in the mix. There is a continuous permeability reduction with increasing combined MK and steel fiber addition reaching 77.9% as maximum value for the mix of 20% metakaolin and 60 kg of steel fiber. Also, there is a reduction of weight and compressive strength losses of RCC subjected to freezing and thawing cycles up to 300 due to MK and steel fiber addition. It is concluded that using a combination of MK and steel fiber has a promised future to be used in more durable RCC for road construction.
Journal of Studies in Science and Engineering
In reinforced concrete structures, the beam-column connection area has a considerable influence o... more In reinforced concrete structures, the beam-column connection area has a considerable influence on the behavior of the structure. The use of fiber-reinforced polymer FRP to strengthen the connections in the Reinforced structure can be one of the solutions to transform this area, thus improving the behavior of the structure, which is achieved through the use of fiber-reinforced polymer of carbon to achieve high-strength concrete beam-column connections Investigations have been conducted using finite element modeling. The concrete damage plasticity model has been used to analyze the model. The results show that the bearing capacity has developed considerably, but the ductility is also significantly reduced. The study also evaluated the qualities of various reinforcement models and proposed the most effective reinforcement model. The use of fiber-reinforced polymer in the flex zone with fibers oriented at forty-five degrees in the shear zone of the joint showed the most significant cha...
The Journal of the University of Duhok, 2020
The use of chemical admixtures in concrete is a common practice in modern construction. Although ... more The use of chemical admixtures in concrete is a common practice in modern construction. Although chemical admixtures improve the properties of concrete but also create leaching problem and they are responsible for environmental pollution. The Impact of chemical admixture on environmental can occur when chemical admixtures are exposed to the environment or when dumping concrete granulate containing admixtures after the demolition of a structure or when concrete granulate is used as gravel replacement in construction and as the concrete admixtures are very readily soluble in water, hence create an environmental problem due to leaching. This paper presents a critical review of several natural materials used in concrete as an admixture that influences the mechanical and durability properties of concrete. This kind of admixtures can be considered as an eco-friendly one with regard the impact on the environment and of low cost compared with the chemical admixture.
Case Studies in Construction Materials, 2021
There is a general belief that admixture can improve some important properties of concrete, and d... more There is a general belief that admixture can improve some important properties of concrete, and different kinds of admixtures are in use worldwide. In the current investigation, a comparative experimental study has been performed on using grape and mulberry extracts as a natural admixture and chemical admixture for concrete. Increasing of workability and reduction in water absorption were observed due to the addition of natural admixtures to concrete. There was an enhancement of concrete compressive strength tested at 3, 7, and 28 days and the 28 days modulus of elasticity as a result of using different admixtures, but reduction of splitting tensile strength was observed. In general, using the two natural admixtures has a beneficial effect to improve both fresh and hardened properties of concrete and they have a superiority on the chemical admixture with regard the cost and producing environmental-friendly construction material.
Journal of Studies in Science and Engineering, 2022
In reinforced concrete structures, the beam-column connection area has a considerable influence o... more In reinforced concrete structures, the beam-column connection area has a considerable influence on the behavior of the structure. The use of fiber-reinforced polymer FRP to strengthen the connections in the Reinforced structure can be one of the solutions to transform this area, thus improving the behavior of the structure, which is achieved through the use of fiber-reinforced polymer of carbon to achieve high-strength concrete beam-column connections Investigations have been conducted using finite element modeling. The concrete damage plasticity model has been used to analyze the model. The results show that the bearing capacity has developed considerably, but the ductility is also significantly reduced. The study also evaluated the qualities of various reinforcement models and proposed the most effective reinforcement model. The use of fiber-reinforced polymer in the flex zone with fibers oriented at forty-five degrees in the shear zone of the joint showed the most significant changes in behavior. The demolition of reinforced concrete beam-column joints is a sudden failure without prior notice, since the collapse of the column and the connection before the break of the beam are undesirable, their occurrence can cause irreparable damage.
Case Studies in Construction Materials, 2021
There is a general belief that admixture can improve some important properties of concrete, and d... more There is a general belief that admixture can improve some important properties of concrete, and different kinds of admixtures are in use worldwide. In the current investigation, a comparative experimental study has been performed on using grape and mulberry extracts as a natural admixture and chemical admixture for concrete. Increasing of workability and reduction in water absorption were observed due to the addition of natural admixtures to concrete. There was an enhancement of concrete compressive strength tested at 3, 7, and 28 days and the 28 days modulus of elasticity as a result of using different admixtures, but reduction of splitting tensile strength was observed. In general, using the two natural admixtures has a beneficial effect to improve both fresh and hardened properties of concrete and they have a superiority on the chemical admixture with regard the cost and producing environmental-friendly construction material.
IOP Conference Series: Materials Science and Engineering, 2020
The reaction of ground granulated blast furnace slag (GGBFS) with water is slower compared to the... more The reaction of ground granulated blast furnace slag (GGBFS) with water is slower compared to the hydration of ordinary Portland cement. This led researchers to concentrate on increasing the hydration rate of the GGBFS. Previous studies were done by (SCA) showed that GGBFS can be used with activators or a certain amount of Portland cement. Also, they found that alkali hydroxides and GGBFS can be reacted alone without any calcium hydroxide obtained from Portland cement hydration to obtain a strong cement paste in applications. This experimental study conducted by the TS EN 196-1 standard, with the ratio (79:21)% slag to cement and 0%, 1%, 2%, 3% and 4% levels of activators (CaCO3, Ca (OH) 2, Na2SO4, K2SO4 and CaSO4.2H2O); results indicates that with above ratio slag can be used with activator of (Na2SO4, K2SO4 and CaSO4.2H2O) ,greater compressive strength of 5-6 MPa was obtained at 2 and 7-day curing ages when K2SO4 was used as an activator at the dosages of 3% and 4%, while the activator (CaSO4.2H2O) can improve all ages, and there was not a clear difference among control mixture without activator and slag-mortars activated by CaCO3 and Ca (OH).
Journal of University of Duhok, 2020
The use of chemical admixtures in concrete is a common practice in modern construction. Although ... more The use of chemical admixtures in concrete is a common practice in modern construction. Although chemical admixtures improve the properties of concrete but also create leaching problem and they are responsible for environmental pollution. The Impact of chemical admixture on environmental can occur when chemical admixtures are exposed to the environment or when dumping concrete granulate containing admixtures after the demolition of a structure or when concrete granulate is used as gravel replacement in construction and as the concrete admixtures are very readily soluble in water, hence create an environmental problem due to leaching. This paper presents a critical review of several natural materials used in concrete as an admixture that influences the mechanical and durability properties of concrete. This kind of admixtures can be considered as an eco-friendly one with regard the impact on the environment and of low cost compared with the chemical admixture.
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Papers by HERSH H A M A A M I N F Mahmood