Abstract
Transparency, excellent toughness, thermal stability and a very good dimensional stability make Polycarbonate (PC) one of the most widely used engineering thermoplastics. Polycarbonate market include electronics, automotive, construction, optical media and packaging. One alternative for reducing the environmental pollution caused by polycarbonate from electronic waste (e-waste), is to use it in cement concretes. In this work, physical and chemical characterization of recycled polycarbonate from electronic waste was made, through the analysis by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM). Then cement concrete was made with Portland cement, sand, gravel, water, and this recycled polycarbonate. Specimens without polycarbonate were produced for comparison purposes. The effect of the particle sizes and concentrations of recycled polycarbonate within the concrete, on the compressive strength and density was studied. Results show that compressive strength values and equilibrium density of concrete depend on the polycarbonate particle sizes and its concentrations; particularly the highest compressive strength values were 20% higher than that for concrete without polycarbonate particles. Moreover, morphological, structural and crystallinity characteristics of recycled polycarbonate, are suitable for to be mixed into concrete.
Key Words
polycarbonate; recycling; electronic waste; cement concrete; compressive strength
Address
Ana L. De la Colina-Martinez: Posgrado en Ciencia de Materiales, Facultad de Quimica, Universidad Autónoma del Estado de Mexico, Paseo Colon esquina Paseo Tollocan S/N, 50180 Toluca, MEX, Mexico
Gonzalo Martinez-Barrera: Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA), Facultad de Quimica. Universidad Autonoma del Estado de Mexico, Km. 12 de la Carretera Toluca-Atlacomulco, 50200 San Cayetano, MEX, Mexico
Carlos E. Barrera-Diaz: Centro Conjunto de Investigacion en Química Sustentable UAEM-UNAM, Universidad Autonoma del Estado de Mexico Campus El Rosedal, Autopista Ixtlahuaca-Atlacomulco, Km 14.5, 50200 San Cayetano, MEX, Mexico
Liliana I. Ávila-Cordoba: Facultad de Ingenieria, Universidad Autónoma del Estado de Mexico, Avenida Universidad S/N, Cerro de Coatepec, Ciudad Universitaria, 50110 Toluca, MEX, Mexico
Fernando Urena-Nunez: Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, 52750 La Marquesa Ocoyoacac, MEX, Mexico
Abstract
The disposal of polythene waste and fly ash is causing serious threat to the environment. Aim of this study is to decrease environmental pollution by using polythene waste and fly ash in concrete. In this study, cement was partially replaced with 0%, 5%, 10%, 15% and 20% fly ash (by weight) and plastic waste was added in shredded form at 0.6% by weight of concrete. The specimens were prepared for the concrete mix of M25 grade and water to cementitious material ratio (w/c) was maintained as 0.45. Fresh concrete property like workability was examined during casting the specimens. Hardened properties were found out by carrying out the experimental work on cubes, cylinders and beams which were cast in laboratory and their behavior under test were observed at 7 & 28 days for compressive strength and at 28 days for density, flexural strength, dynamic modulus of elasticity, abrasion resistance, water permeability and impact resistance.
Overall results of this study show that addition of 0.6% (by weight of the concrete) plastic waste with 10% (by weight of cement) replacement of cement by fly ash result an improvement in properties of the concrete than conventional mix.
Key Words
fly ash; plastic waste; workability; density; compressive strength; flexural strength; dynamic modulus of elasticity; abrasion resistance; water permeability; impact resistance
Address
Gopal Paliwal and Savita Maru: Department of Civil Engineering, Ujjain Engineering College, Ujjain (M.P.), India
Abstract
This study focused on the influences regarding the use of polyepoxide-based polymer and silica fume (SF) on the fresh and hardened state properties of self-compacting lightweight concrete (SCLC) along with their impacts on electrical resistance and ultrasonic pulse velocity (UPV). To do so, two series of compositions each of which consists of twelve mixes, with water to binder (W/B) ratios of 0.35 and 0.4 were cast. Three different silica fume/binder ratios of 0, 5%, and 10% were considered along with four different polymer/binder ratios of 0, 5%, 10%, and 15%. Afterwards, the rupture modulus, tensile strength, 14-day, 28-day, and 90-day compressive strength, the UPV and the electrical resistance of the mixes were tested. The results indicated that although the use of polymer could enhance the passing and filling abilities, it could lead to a decrease of segregation resistance. In addition, the interaction of the SF and the polymeric contents enhanced the workability. However, the impacts regarding the use of polymeric contents on fresh state properties of SCLC were more prevalent than those regarding the use of SF. Besides the fresh state properties, the durability and mechanical properties of the mixes were affected due to the use of polymeric and SF contents. In other words, the use of the SF and the polymer enhanced the durability and mechanical properties of SCLC specimens.
Address
Moosa Mazloom, Ali Allahabadi and Mohammad Karamloo: Department of Civil Engineering, Shahid Rajaee Teacher Training University, Lavizan, Tehran, Iran
Abstract
In this paper, an experimental investigation was carried out to study the effect of volume fraction of fiber and maximum aggregate size on mode-I fracture parameters of high strength concrete. Total of 108 beams were tested on loading frame with three point loading, the variables in the high strength concrete beams are aggregate size (20 mm, 16 mm and 10 mm) and volume fraction of fibers (0%, 0.5%, 1% and 1.5%). The fracture parameters like fracture energy, brittleness number and fracture process zone were analyzed by the size effect method (SEM). It was found that fracture energy (Gf) increases with increasing the Maximum aggregate size and also increasing the volume of fibers, brittleness number (B) decreases and fracture process zone (CF) increases.
Key Words
high strength concrete; mode I fracture energy; fracture process zone; brittleness number; steel fiber
Address
Ch.Naga Satish Kumar, P.V.V.S.S.R. Krishna and D.Rohini Kumar: Department of Civil Engineering, Bapatla Engineering College, Bapatla-522101, India
Abstract
The flexural behavior of Fiber reinforced polymer (FRP) sheets has gained much research interest in the flexural strengthening of reinforced concrete beams. The study on flexure includes various parameters like increase in strength of the member due to the externally bonded (EB) Fiber reinforced polymer, crack patterns, debonding of the fiber from the structure, scaling, convenience of using the fibers, cost effectiveness, etc. The present work aims to study experimentally about the reasons behind the failure due to flexure of an externally bonded FRP concrete beam. In the design of FRP-reinforced concrete structures, deflection control is as critical as much as flexural strength. A numerical model is created using Finite element (FEM) software and the results are compared with that of the experiment.
Key Words
GFRP; CFRP; flexural study; external bonding; numerical analysis
Address
Sumathi A. and Arun Vignesh S.: School of Civil Engineering, SASTRA University, Thanjavur 613401, India
Abstract
Very limited studies have been accomplished concerning the historical structures around Harran area. Collected mortar samples from the historic structures in the area were tested to explore their mechanical, chemical and mineralogical properties. Mortar samples from three different points of each historical structure were taken and specified in accordance with the related standards taking into consideration their mechanical, chemical and mineralogical properties. By means of SEM-EDX the presence of organic fibres and calcite, quartz, plagioclase and muscovite minerals has been examined. Additionally, by means of XRF analysis, oxide (SiO2, Al2O3, and Fe2O3) percentages of mortar ingredients have been specified, also. According to the test results obtained, it was confirmed that the mortars had densities ranging between 1.51-2.10 g/cm3, porosity values ranging between 8.89-35.38% and compressive strengths ranging between 5.02-5.90 MPa.
Specimen HU, which has the highest durability and lowest water absorption and porosity, was the mortar taken from the most intact building in the mosque complex. This result is most likely due to the very little fine aggregate content of HU. In contrast, HUC mortars with a small amount of fine particles and brick contents yielded slightly lower compressive strengths. The interesting point of this study is the mineralogical analysis results and especially the presence of ettringite in these historic mortars linked to the use of pozzolanic materials. Survival of these historic structures in Harran Area through centuries of use and, also, having been subjected to many earthquakes can probably be explained by these properties of the mortars.
Key Words
harran; mortars; physico-chemical
Address
Hanifi Binici: Ceyhan Construction Company, Baskonus Street, Beyza Apt.9, Kahramanmaras, Turkey
Mehmet Akcan: Department of Civil Engineering, Kahramnaras Sutcu Imam University, Kahramanmras 46100, Turkey
Orhan Aksogan: Toros University, Department of Civil Engineering, Mersin 33140, Turkey
Rifat Resatoglu: Near East University, Nicosia, North Cyprus
Abstract
Grouts compared to other material sources, could be highly sensitive to cold weather conditions, especially when the compressive strength is the matter of concern. Grout as one the substantial residential building material used in retaining walls, rebar fixation, sidewalks is in need of deeper investigation, especially in extreme weather condition. In this article, compressive strength development of four different commercial grouts at three temperatures and two humidity rates are evaluated. This experiment is aimed to assess the grout strength development over time and overall compressive strength when the material is cast at low temperatures. Results represent that reducing the curing temperature about 15 degrees could result in 20% reduction in ultimate strength; however, decreasing the humidity percentage by 50% could lead to 10% reduction in ultimate strength. The maturity test results represented the effect of various temperatures and humidity rates on maturity of the grouts. Additionally, the freeze-thaw cycle\'s effect on the grouts is conducted to investigate the durability factor. The results show that the lower temperatures could be significantly influential on the behavior of grouts compared to lower humidity rates. It is indicated that the maturity test could not be valid and precise in harsh temperature conditions.
Abstract
Commonly used concrete in general, consists of cement, fine aggregate, coarse aggregate and water. Natural river sand is the most commonly used material as fine aggregate in concrete. One of the important requirements of concrete is that it should be durable under certain conditions of exposure. The durability of concrete is defined as its ability to resist weathering action, chemical attack or any other process of deterioration. Durable concrete will retain its original form, quality and serviceability when exposed to its environment. Deterioration can occur in various forms such as alkali aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts, shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground water, sea water attack and corrosion caused by salts. Addition of admixtures may control these effects. In this paper, an attempt has been made to replace part of fine aggregate by tailing material and part of cement by fly ash to improve the durability of concrete. The various durability tests performed were chemical attack tests such as sulphate attack, chloride attack and acid attack test and water absorption test. The concrete blend with 35% Tailing Material (TM) in place of river sand and 20% Fly Ash (FA) in place of OPC, has exhibited higher durability characteristics.
Key Words
iron ore tailing; fly ash; compressive strength; chemical attack; durability
Address
B.M.Sunil, Manjunatha L.S. and Subhash C. Yaragal: Department of Civil Engineering, National Institute of Technology, Surathkal, Karnataka, India
