Adil al-Tamimi - Academia.edu (original) (raw)

Papers by Adil al-Tamimi

Concrete, despite being one of the most produced materials in the world, still has weaknesses and... more Concrete, despite being one of the most produced materials in the world, still has weaknesses and drawbacks. Significant concern of the cementitious materials in structural applications is their quasi-brittle behavior, which causes the material to crack and lose its durability. One of the very recently proposed mitigations for this problem is the implementation of nanotechnology in the concrete mix by adding carbon nanotubes (CNTs) to it. CNTs can enhance the critical mechanical properties of concrete as a structural material. Thus, this paper demonstrates a state-of-the-art review of reinforcing concrete with CNTs, emphasizing on the structural performance. It also goes over the properties of CNTs alone, the present methods and costs associated with producing them, the possible special applications of concretes reinforced with CNTs, the key challenges and drawbacks that this new technology still encounters, and the most reliable practices and methodologies to produce CNT-reinforced...

World Academy of Science, Engineering and Technology, International Journal of Architectural and Environmental Engineering, 2015

Most of the welding of cast iron is repair welding. Carbon pickup and resulting cracks are the ma... more Most of the welding of cast iron is repair welding. Carbon pickup and resulting cracks are the main concerns when welding CI. The casting process is never perfect, especially when dealing with large components. Instead of scrapping defective castings, they can often be repaired by welding. Naturally, the very high carbon concentration of typical CIs causes difficulties by introducing brittle martensite in the heat-affected zone of weld. It is therefore necessary to preheat to a temperature of 650 °C, followed by slow cooling after welding, to avoid cracking. The welding was carried out with manual shielded metal arc welding using ENiFe-CI filler metal. Shielded metal arc welding process using a nickel electrode was used to join a grey cast iron. The effect of pre heating on the microstructure, hardness, tensile and toughness was studied than the effect of post weld heat treatment (PWHT) on the microstructure, hardness, tensile and toughness was studied after that the same was tested on the preheated and post weld heat treated specimens. After that we concluded that which heat treatment process is suitable for cast iron weld.

Environmental Technology & Innovation, 2021

Abstract The environment impact of de-oiling and re-activation process of spent clay from oil ind... more Abstract The environment impact of de-oiling and re-activation process of spent clay from oil industry was evaluated. The process includes many technical steps; de-oiling the entrained spent clay using solvent extraction techniques; solvent recovery process; re-activation process wherein the oil-free spent clay is treated with acid; and thermal polishing step at high temperature to increase the activity. Many solvents were used for de-oiling steps. The performance of solvent for oil recovery can be categorize as follow: Tri-chloromethane > di-chloromethane > MEK > stabilized condensate > 1-butanol > ethyl acetate > LPG condensate > toluene > hexane > 2-propanol The reactivated spent clay was applied for one step reclamation process of waste lubricating oil. It is adsorption–extraction process with solvent and additive. The activity of reactivated spent clay was compared with virgin clay during reclamation process. The reclaimed lubricating oil was analyzed for different physical properties. It was found that the reactivation process of spent clay from acid treatment followed by thermal treatment gave the best results.

ACI Materials Journal, 2003

This study was part of a large-scale experimental program on the Brite-Euram research project: R... more This study was part of a large-scale experimental program on the Brite-Euram research project: Rational Production and Improved Working Environment through Using Self-Consolidating Concrete (SCC). The University of Paisley was responsible for a major part of Task 4 on ...

3D concrete printing is one of the most innovative and modern techniques in the field of construc... more 3D concrete printing is one of the most innovative and modern techniques in the field of construction that achieved several milestones in that field for the following advantages: saving project's time, ability to execute complicated shapes, reduce waste and low cost. However, the concept of 3D printing in UAE is relatively new where construction teams, including clients, consultants, and contractors, do not have the required knowledge and experience in the field. This is the most significant obstacle for the construction parties, which make them refrained from using 3D concrete printing compared to conventional concreting methods. This study shows the historical development of the 3D concrete printing, its advantages, and the challenges facing this innovation. Concrete mixes and materials have been proposed and evaluated to select the best combination for successful 3D concrete printing. The main characteristics of the 3D concrete printing in the fresh and hardened states are co...

Buildings, 2019

The construction industry consumes enormous quantities of concrete, which subsequently produces l... more The construction industry consumes enormous quantities of concrete, which subsequently produces large amount of material waste during production and demolishing. As a result, the colossal quantity of concrete rubble is disposed in landfills. This paper, therefore, evaluated the feasibility of reusing waste concrete as recycled aggregate (RA) to produce concrete. The replacement levels were 20, 50, and 80% RA of normal coarse aggregate. Micro silica (MS) and fly ash (FA) were used as cementitious replacement material, however, the water-to-binder ratio (w/b) was kept constant at 0.31. A total of 44 specimens were used to evaluate the fresh and hardened properties. Concrete with 80% RA showed good workability and mechanical properties. The compressive strength of the concrete with 80% RA was 60 MPa at 28 days and 77 MPa at 56 days. Rapid chloride penetration test (RCPT) was also conducted, where the concrete with 80% RA had the lowest permeability.

Environmental Technology & Innovation, 2018

Soil remediation was investigated from waste oil contamination. Contamination of different soil p... more Soil remediation was investigated from waste oil contamination. Contamination of different soil particle diameters was prepared with different dosage of waste oil contamination. Solvent extraction technique was employed for remediation using batch process. The contaminated soil was treated with many solvents and different solvents to oil ratios. The solvent was recovered and reused. The soil and waste oil were analyzed before and after remediation process to study the performance of soil remediation process. A mathematical model for remediation process was constructed. The performance of different solvents for soil remediation is as follow: LPG Condensate > Dichloromethane > Trichloromethane > MEK > Stabilized Condensate > Hexane > Heptane >1-butanol > toluene > ethyl acetate > 2-propanol Physical properties of recovered waste oil showed lower carbon residue, ash content, and asphaltene content due to the adsorption of heavy molecular weight hydrocarbons inside the pores of the soil after extraction process. The treated soil may need further regeneration process to recover it from the entire heavy molecules. Two stages extraction process was performed to remove all the heavy constituents from the pores of the contaminated soil.

Sustainability

In this paper, we present a strength and deformation evaluation of earth blocks reinforced with d... more In this paper, we present a strength and deformation evaluation of earth blocks reinforced with different types of fiber. A natural palm tree fiber and two other types of synthetic polyolefin fibers were used to improve earth blocks’ strength and stiffness. The soil used to cast the earth blocks was composed of dune sand, which is extensively available in the United Arab Emirates and most Gulf Cooperation Council (GCC) deserts, and clayey silt soil acquired from Al-Ain city, UAE. Sixteen different mixes were prepared for this study. Two identical earth blocks were cast in a wooden mold from each mix to form a total of 32 blocks. After compaction, the blocks were consolidated under pre-specified pressure, air dried, and tested to failure in the compression machine. The main parameters investigated in this study were clay content, fiber types and percentages, and cement content. The results indicate that the addition of natural or polymeric fiber to cast earth blocks significantly imp...

Industrial Engineering & Management, 2017

One of the chief goals of the construction industry is to maintain a safe environment at construc... more One of the chief goals of the construction industry is to maintain a safe environment at construction sites, a goal best achieved by implementing Quality Management. Deming's Total Quality Management (TQM) tools serve as an excellent option when it comes to efficiently using available resources to improve construction management at the site. Various accidents in the construction sites, however, may still occur, leading to loss of lives, delays and increasing project cost. Thus, an effective safety management system should be enforced to mitigate these accidents so as to reduce delay, cost and most importantly, prevent harmful accidents. A combination of TQM and Total Safety Management (TSM) ranks as one of the best available practices that establish a safe environment at the construction sites. In this paper, a survey has been designed, conducted and analyzed in order to solicit feedback from 61 engineers working in various construction companies and organizations in the UAE. Two construction processes that necessitate safety management are studied: safety of tower cranes and temporary formwork. The interrelationship between safety, quality, and reliability is also discussed along with the various causes of failure. The results of the survey reveal that the majority of the survey participants had implemented routine safety and health procedures to avoid accidents. The number of accidents, however, was still inordinately high due to top management pressurizing middle managers into completing construction goals within a designated time period.

The movement towards high performance buildings has been strong in the recent years. This can be ... more The movement towards high performance buildings has been strong in the recent years. This can be also noticed in the Middle East, especially United Arab Emirates (UAE). Recently, UAE’s energy council approved the idea to retrofit old buildings toward green buildings. The major component of it is the reduction in energy consumption. Similarly, leading education institutes in the Middle East such American University of Sharjah (AUS) is also taking steps towards sustainable construction. Recently, one of the buildings at AUS was awarded with the green building certification. This study compares the recently awarded building with a non-green building at AUS. Comparison is held in terms of energy consumption and carbon footprint of both the buildings. The results showed that green buildings have significant lower energy consumption than existing building. The carbon footprint savings per m for a green building are shown to be 42 kg CO2e/m. In addition to this, U-value of non-green buildi...

Carbon Fiber Reinforced Polymer (CFRP) has found great applications in the building and construct... more Carbon Fiber Reinforced Polymer (CFRP) has found great applications in the building and construction industry. However; there is a limited theoretical and experimental research in this area. This report investigates the durability of the bonding between external CFRPs and the concrete. Partially loaded CFRP concrete samples at various load intensity were subjected to several sets of environmental exposure conditions. The studied parameters include actual marine environment (provided by AUS and placed in the Construction Materials Lab), loading effects, humidity and moisture, high thermal effects, and ageing tests. The main purpose of this project is to develop a method for estimating the reduction in bond properties due to combinations of the above exposures that are used as a degradation measures. The design team utilized the various relevant courses studied at AUS in structural and material areas to achieve our goals. The obtained results will provide new systematic technical data...

International Journal of Geomate, 2015

Strengthening and rehabilitation have been increasingly applied in many structures to improve the... more Strengthening and rehabilitation have been increasingly applied in many structures to improve their capacity and serviceability. Fiber Reinforced Polymer (FRP) materials are universally known for their ability to improve the load capacity of damaged structural elements because of their high linear-elastic behavior. However, enhancing the capacity of structural elements that are exposed to repeated load coupled with harsh environment is an area that requires further investigation. This research focused on experimental analysis of the behavior and response of confined and unconfined concrete compression members (300mm x 150mm) under repeated load while exposed to 1440 cycles of seawater splash zone in United Arab Emirates (UAE). Confining concrete compression members with Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) sheets have increased the load capacity compared to the control sample at room temperature by 110% and 84%, respectively. Results showed that the average value of compressive strength for the confined concrete exposed to sea water splash zone conditions for CFRP and GFRP specimens has decreased by 33% and 23%, respectively, compared to the confined concrete in the room temperature. However, GFRP specimens showed higher performance in compressive strength under sea water splash zone than those of the CFRP specimens. Different mode of failures such as delamination, debonding and combination of such modes were observed and related to various exposure factors and mechanical properties.

Construction and Building Materials, 2016

Abstract The outstanding mechanical properties of carbon nanotubes (CNTs) highlight them as poten... more Abstract The outstanding mechanical properties of carbon nanotubes (CNTs) highlight them as potential candidates for cementitious material reinforcement. However, their low surface friction and the Van der Waals forces of attraction between them, cause the CNTs to aggregate with each other rather than bind with the cement matrix. A number of methods have been investigated by researchers to reduce the aggregation, improve dispersion and activate the graphite surface to enhance its interfacial interaction. These methods involve surface functionalization and coating, optimal physical blending, use of surfactant and other admixtures. This research investigates the use of silica fumes (an admixture), surface functionalized CNTs and cement paste to overcome those obstacles. CNTs with polar impurities end groups OH and COOH were examined. Mortar samples with non-functionalized CNTs dispersed in water solution, another with non-dispersed, non-functionalized CNTs, and a third batch with no CNTs (as control) was used also studied. Silica fumes volume fraction was varied from 0 to 30% to determine its effect. Compressive and flexural strengths of the different mixes were measured and compared. Qualitative analysis using Scanning Electron Microscope (SEM) and Energy-Dispersive Spectroscopy (EDS) were carried out to study the morphology of each mix. Results reveal a much higher enhancement in strength both compressive and flexural strengths for the functionalized CNTs with 30% silica fumes over the other samples.

Study of Civil Engineering and Architecture, 2014

Waste crumb rubber has been used as one of the modified binding material for asphalt production. ... more Waste crumb rubber has been used as one of the modified binding material for asphalt production. Three percentages of crumb rubber of 5, 10, and 15% by mass of the binder content were considered to produce crumb rubber modified bitumen “CRMB”. It is proposed that different percentages of crumb rubber modified bitumen (CRMB) were mixed with the asphaltic concrete and used in paving roads. The new mix contains relatively small amount of CRMB in addition to aggregate, asphalt binder and air. Marshall Stability and flow, density, void analysis, and other characteristic tests were conducted for all these samples to evaluate the asphalt concrete road according to UAE standards. From these tests it was clearly shown that the addition of waste rubber crumb had a significant effect on the behavior of final asphalt paving road. It was found that; the more percentage added of rubber tire the higher voids in mineral aggregate; 5% rubberized bitumen yielded the maximum amount of strength among other percentages. The less the amount of rubber in the mix the higher flow can be gained; 15% of CR gave the maximum viscosity; furthermore, ductility was determined for all results. Results showed that the higher the amount of rubber crumb in the bitumen, the more chance of the sample to recover after the load is released.

Composite Structures, 2016

Carbon fibre reinforced polymer (CFRP) sheet has gained its popularity to retrofit civil structur... more Carbon fibre reinforced polymer (CFRP) sheet has gained its popularity to retrofit civil structures which is bonded externally, typically on the soffit of a beam. In this study, the bond between carbon fibre reinforced polymer (CFRP) and concrete is improved by modifying the property of commercial epoxy and compared against normal epoxy. The deterioration in bond strength was produced by placing the beam into salt water under wet dry cycles. Also, a model is proposed to determine the bond strength from flexural test and compared against the available bond strength models which are typically obtained from pull out test. This proposed model shows promising results in terms of predicting the bond strength from flexural test. In addition, a strength reduction factor is introduced to incorporate the effect of wet dry cycles to predict the long term behaviour. It is found that the modified epoxy enhance the ductile property and bond strength.

New Horizons and Better Practices, 2007

... a variety of different projects. Also, concrete is the most widely used construction material... more ... a variety of different projects. Also, concrete is the most widely used construction material here in the UAE and is used in virtually all projects regardless of the nature of size of the project. However, there are different ways of ...

Journal of Materials in Civil Engineering, 2015

AbstractStrengthening and retrofitting structural members using carbon fiber reinforced polymer (... more AbstractStrengthening and retrofitting structural members using carbon fiber reinforced polymer (CFRP) materials has gained wide acceptance in the civil engineering community because of their superior mechanical properties, light weight, corrosion resistance, and ease of use. Numerous structural reinforced concrete (RC) members have been strengthened with externally-bonded CFRP plates using epoxy adhesives that produce an increase in their load-carrying capacities. However, there are some uncertainties regarding the durability of the bond between the concrete and FRP interfaces when subjected to severe environmental exposure. Most strengthening applications are exposed to outdoor conditions and hence durability under aggressive environments must be considered. This is the subject of this investigation. Several CFRP-concrete prisms have been subjected to several sets of environmental exposure conditions and preloaded with 3 and 5 kN of sustained loading, amounting to approximately 15 and 25% of ultimate lo...

2011 Fourth International Conference on Modeling, Simulation and Applied Optimization, 2011

A rock failure criterion is very important for prediction of the ultimate strength in rock mechan... more A rock failure criterion is very important for prediction of the ultimate strength in rock mechanics and geotechnics; it is determined for rock mechanics studies in mining, civil, and oil wellborn drilling operations. Also shales are among the most difficult to treat formations. Therefore, in this research work, using the artificial neural network (ANN), a model was built to predict the ultimate strength of shale, and comparison was made with support vector machine (SVM), multiple linear regression models, and the widely used conventional polyaxial failure criteria in the stability analysis of rock structures, Drucker-Prager, and Mogi-Coulomb. For building the model, the corresponding results of triaxial and polyaxial tests have been performed on shales by various researchers. They were collected from reliable published articles. The results obtained showed that a feed forward back propagation multi-layer perceptron (MLP) was used and trained using the Levenberg-Marquardt algorithm, and the 2-4-1 architecture with root-mean-square-error (RMSE) of 24.41 exhibits a better performance in predicting the ultimate strength of shale in comparison with the investigated models. Also for further validation, triaxial tests were performed on the deep shale specimens. They were prepared from the Ramshire oilfield in SW Iran. The results obtained were compared with ANN, SVM, multiple linear regression models, and the conventional failure criterion prediction. They showed that the ANN model predicted ultimate strength with a minimum error and RMSE being equal to 43.81. Then the model was used for prediction of the threshold broken pressure shale layer in the Gachsaran oilfield in Iran. For this, a vertical and horizontal stress was calculated based on a depth of shale layer. The threshold broken pressure was calculated for the beginning and ending of a shale layer to be 154.21 and 167.98 Mpa, respectively.

Corrosion and Materials in the Oil and Gas Industries, 2013