Civil Engineering and Materials

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Authors: Šárka Keprdová, Jiří Bydžovský
Abstract: Combining air or hydraulic binders with hemp shives, we can gain a set of new building materials. These products achieve excellent performance characteristics for durable, environmentally sustainable buildings. Being together, these products create natural composite building material that can be used to create insulating elements for walls, floors and roofs and also to create excellent thermal and acoustic properties of the buildings. Hemp insulation material is created by connection of technical hemp shives with a binder consisting of cement and calcium hydroxide. The production process may vary depending on whether the hemp is mineralized or not. It can be generally said that dry components should be mixed at first (binder and shives) and then water should be added. During the production, all components of insulating material must be perfectly mixed. The paper deals with the proposal and testing of new hemp insulation composites. Tests of the hemp insulation described in this paper are not typical representatives of the tests of insulation materials. Due to the doubts about the insulating properties of the proposed material, there was testing carried out in such the ways as if it was the filling material based on lightweight concretes.
Authors: Kamal M. Bajoria, Rajan L. Wankhade
Abstract: Piezolaminated smart structures are becoming more popular as they can be used as light weight structures to control structural response in various structural applications. Piezoelectric materials have direct and converse piezoelectric effects which can be adequately employed to control the deflection, shape and vibration of the structure. A finite element methodology based on higher order shear deformation theory is developed for free vibration analysis of smart piezolaminated composite plates subjected to combined action of electrical and mechanical loading. To achieve the accurate prediction of the frequencies, a finite 2D isoparametric element for the mechanical displacement field is combined with an electric potential field. Numerical results are presented for free vibration analysis of simply supported piezolaminated composite plate considering different electric condition with varying thickness to span ratio.
Authors: Rashid Tanzadeh, Mahyar Arabani
Abstract: Modification of the asphalt binder is one approach taken to improve aged pavement performance. To make the most of maintenance budgets, many agencies have resorted to the use of asphalt rejuvenators as an alternative to revive aging and brittle asphalt pavements. The purpose of this study is laboratory research on the effect of asphalt emulsion in restoring the original properties of aged asphalt pavement. For this purpose, the repeated load axial test is carried out on conventional asphalt samples and aged asphalt samples containing rejuvenator agents in different stress and rejuvenator percentage. Bitumen aged with RTFO according to ASTM-D2872 and the optimum bitumen of 5.5% were considered. The softening point and penetration tests, to examine the effect of rejuvenator in asphalt mixtures modification, On the basic, aged and modified aged bitumen were performed. The results represent that asphalt emulsion as a rejuvenator material in aged asphalt samples because of suitable performance improve aged asphalt permanent deformation resistance and aged bitumen Rheological property.
Authors: Amir Kavussi, Rashid Tanzadeh
Abstract: Recycling of bituminous mixes is extending worldwide with the aim of conserving natural resources and the environment. Rejuvenating agents are generally used in recycling processesin order to soften the aged binders in mixes. Cutback bitumens have been used in Iran mainly in preparing conventional cold mixes. However, the long term good performance of these cold mixes in various parts of the country has shown less hardening of these mixes, compared with conventional HMA mixes. In this research the application of a cutbackbitumen has been investigatedas a rejuvenating agent in mixes containing laboratory aged binders. A 60-70 penetration grade bitumen from Refinery of Tehran was aged under Thin Film Oven Testing (TFOT) conditions. Asphalt Concrete samples were prepared using TFOT aged and virgin binders. Additional samples were prepared using the aged binders together with various amounts of a slow curing SC-250 cutback bitumen from the above refinery. The compacted four inchdiameter samples were tested under static creep testing. The results showed promising effects of the cutback binder in rejuvenating the aged mixes. Based on the results of this study, a mix design criteria wasset for recycled mixes containing cutback bitumen as the rejuvenating agent.
Authors: Jabbar Abbas Jabir Al Khafaji, Najah Mahdi Lateef Al Maimuri, Abdul Hadi Meteab Hassan Al Sa'adi
Abstract: A study of a mechanical performance(Compressive strength, flexural strength, and splitting tensile strength)of self-compacting (SCC) and conventional (NCC)concretemixes and some physical properties of the mixes made of Portland cement under the effect of acidic solution attackare made. Trichloroacetic and Salicycilic acids are selected and used in this study. It is found that the reduction percentage in compressive strength is about 6% and 3% under the effect of Trichloroacetic acidic solution whereas itisabout 8% under the effect the salicycilic acidic solution attackfor both SCC and NCC mixes after 62 days of treatment for bothSCC and NCC mixes respectively. The reduction percentage in flexural strengthisabout 27% and 37% under the effect of the Trichloroacetic acidic solution attack whereas itis about 59% and 79% under the effect the salicycilic acidic solution attackfor both SCC and NCC mixes respectivelyafter 62 days of treatment. The reduction percentage in splitting tensile strength is about 60% and 63% under the effect the Trichloroacetic acidic solution attack whereas it is 70% and 88% under the effect of the salicycilic acidic solution attack% for both SCC and NCC mixes after 62 days of treatment. At the age 90 days, the SCC and NCC mixes have a reductionpercentage in the cubes weight of 3% and 4% whereas there is an increasing in volume of 0.3% and 0.4% respectively under the effect of salicyclic acid solution attack.It is observed that SCC mixes offer more resistant and less deterioration against acidic solutions attack.
Authors: Aminaton Marto, Bakhtiar Affandy Othman, Fauziah Kasim, Ismail Bakar
Abstract: Trial embankment approximately 3 meters height, 10 meters of length, 16 meters width, and a slope of 1V: 2H was completed on soft clay site at RECESS, UTHM, Batu Pahat, Johor, Malaysia. Two embankments were respectively reinforced by a high strength geotextile (HSG) and the combination of bamboo and low strength geotextile or bamboo-geotextile composite (BGC) at the interface between embankment fill and foundation soil. Each embankment was installed with the same geotechnical instrumentation scheme for monitoring purposes. The purpose of this paper is to analyse the field performance for both embankments in terms of improving settlement embankment under the embankment. For this purpose, the settlement under the embankment, settlement at the surface of the embankment and the excess pore water pressure response were measured through geotechnical instrumentation for over 418 days. The results showed that the BGC system is more practical than HSG in terms of settlement and also in terms of cost, without compromising the quality of the embankment performance.
Authors: Zaid Shaker Aljoumaily, Norizal Noordin, Hanizam Awang, Mohammed Zuhear Almulali
Abstract: This study is a part of an on-going research studying the effect of blast furnace slag as a binder and filler replacement on the properties of fresh and hardened foam concrete. A mix having the density of 1300kg/m3 with a proportion of (1 cement:2 sand), W/C ratio of 0.45, a commercially available additive (SP-1), class F fly ash and a unprocessed blast furnace slag was used. The results show that the mix containing the slag achieved a higher compressive strength (6.31MPa at 28 days) than that of the control mix at the same age (5.81MPa). In addition, combining both slag and fly ash as a cement replacement further enhanced the compressive strength achieving higher compressive strengths. Also, a more stable mix was achieved by the slag replacement when compared to the control mix. This result concludes that the unprocessed slag is a good pozzolanic material that can be used with foam concrete.
Authors: Sara Kazemi Yazdi, Salman Masoudi Soltani, Soraya Hosseini
Abstract: Cellulosic materials and cellulose derivatives have been long used in the synthesis of numerous materials. These include various products such as papers, cigarette filters and sanitary pads. Cigarette filters, containing 95% cellulose acetate fibers, are responsible for one of the largest solid wastes generation today. In this work, a simple one-step carbonization of cigarette filters under various operational parameters is used in order to produce porous carbon. The effects of various pyrolysis parameters including carbonization temperature, heating rate and hold time on the final porous carbon product have been investigated. Adsorption-desorption isotherms, scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) as well as thermal gravimetric analysis (TGA) have been employed to characterize the pyrolyzed product. The optimum conditions for the production of porous carbon from cigarette filters in relation to its maximum specific surface area (637 m2/g BET surface area) is understood to be at a heating rate of 5 °C/min at 900 °C for 1 hour.
Authors: Bazid Khan, Abdus Siraj, Riaz A. Khattak
Abstract: The subgrade soil of western by Pass Road Mardan, Pakistan consists of silty clay belonging to A-6(14) group of the AASHTO soil classification system. The average natural moisture content of the soil is more than 18% which makes it susceptible to water logging and problematic for pavement construction. The aim of this research is to improve the supporting power of the existing subgrade material to carry the proposed traffic safely. For this purpose, lime was incorporated into the soil. Soil samples were prepared containing 0, 4, 6, 8, 10 and 12% lime by weight of the soil. Laboratory tests were conducted for determining particle size distribution, Atterberg limits, optimum moisture contents and maximum dry density and California Bearing Ratio (CBR). From this study it was found that the CBR initially increased with increase in lime content, reaching to a maximum value (35.50 %) at 6% lime content and then decreased with further increase in lime content. The optimum lime content for CBR was found as 6.50% (w/w), which enhanced CBR value by 337% compared to control. A consistent decrease from 1.92 at 0 to 1.763 (g/cm3) at 12% lime was observed suggesting compaction in the material. Results suggested that liming subgrade material is a viable option for improving pavement.
Authors: Bozena Vacenovska, Rostislav Drochytka, Vit Černý
Abstract: This paper deals with the chosen hazardous waste solidification/stabilisation (S/S) under the catalogue code 190811 using cement matrix with addition of classic fly ash and fluid fly ash as secondary raw binders. The main task of the research works was a microstructural study of the most successful S/S formula that will be used for development of new reclamation material. The S/S process product was subject to X-Ray analysis and to the electron microscopy analysis two years after its production to evaluate the possibility of degradation of the cement composite and releasing the contaminants into environment.

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