817 research outputs found

    Effects of advera® warm mix additive on the rheological properties of unaged and short term aged asphalt binders

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    The performance of asphalt pavement is mainly governed by the properties of the binder. Many asphalt pavement distress are pronounced to be related to the rheological properties of asphalt binder. The oxidation changes the structure and composition of asphalt binder resulting stiffer and brittle of asphalt. This paper described SuperpaveTM binder that was used to characterize the rheological properties of PG64 asphalt binders blended with various Advera® contents subjected to unaged and short term aged. Rotational viscometer (RV) and Dynamic Shear Rheometer (DSR) were conducted to measure binder properties at higher and intermediate temperature respectively. The results indicated that, the addition of Advera® in the asphalt binder exhibited change in binder rheology which influenced rutting parameteryKeywords: Advera®; Aging; Viscosity; Rotational viscometer; Dynamic shear rheometer

    Physical Characterization of Modified Asphalt Binder with Differing Fly Ash Geopolymer Contents

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    Nowadays, the use of waste material product has gained popularity in the production of asphalt mixes and becomes a cost-effective method of pavement construction that can decrease the consumption of natural resources and to reduce environmental pollution. This research aimed to investigate the possibility of using waste and by-product material namely fly ash geopolymer additive to influence the physical properties of asphalt binder. An experimental matrix of laboratory testing was conducted to study the properties of the 60/70 and 80/100 asphalt binder with modified binder containing 3%, 5%, 7%, 9% and 11% of fly ash geopolymer additive. The physical properties of the binders were determined using the penetration, softening, penetration index, ductility, and rotational viscosity respectively. The results indicated that, the fly ash geopolymer modified binder had improved the physical properties over base binder. The thermal susceptibility also improved by referring to the Penetration Index value. Overall research conclusions are that geopolymer application resulted in a potential enhancement of some of the properties of the asphalt binder and increase the performance of asphalt binder in the pavement application

    Dynamic Creep Performance of Hot Mix Asphalt Mixture Incorporating Fibre

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    Permanent deformation is one of the distress that develops gradually as the number of load applications increases and appears as longitudinal depressions in the wheel paths and small upheavals to the sides. For this reason, numerous studies conducted on modification asphalt binder or mixture by various fibre. This paper presents the evaluation of creep modulus and permanent deformation of modified asphalt mixture with fibres. In order to envisage the modified asphalt mixture, Forta-fi, Kenaf and PET was blended to estimate the creep properties and rut depth value at different loading pattern. Superpave mix design method was employed with NMAS 12.5mm to obtain the optimum bitumen content established at 4% air void. In the respect, bitumen 60/70 penetration grade with 0.5% of Forta-Fi, 0.1% Kenaf fibre and 0.5% PET by weight of asphalt mixture were prepared. Dynamic Creep Test was performed in accordance to the EN 12697-25:2005 guidelines using the Universal Testing Machine (UTM). As the result, the minimum value of permanent deformation was found at 0.5% of PET. Based on these studies, adding a minimum percent of PET in the asphalt mixture shows a better resistance to rutting deformation and enable a better understanding of the properties in modified asphalt mixtures

    Physical Characterization of Modified Asphalt Binder with Differing Fly Ash Geopolymer Contents

    Get PDF
    Nowadays, the use of waste material product has gained popularity in the production of asphalt mixes and becomes a cost-effective method of pavement construction that can decrease the consumption of natural resources and to reduce environmental pollution. This research aimed to investigate the possibility of using waste and by-product material namely fly ash geopolymer additive to influence the physical properties of asphalt binder. An experimental matrix of laboratory testing was conducted to study the properties of the 60/70 and 80/100 asphalt binder with modified binder containing 3%, 5%, 7%, 9% and 11% of fly ash geopolymer additive. The physical properties of the binders were determined using the penetration, softening, penetration index, ductility, and rotational viscosity respectively. The results indicated that, the fly ash geopolymer modified binder had improved the physical properties over base binder. The thermal susceptibility also improved by referring to the Penetration Index value. Overall research conclusions are that geopolymer application resulted in a potential enhancement of some of the properties of the asphalt binder and increase the performance of asphalt binder in the pavement application

    Dynamic Creep Performance of Hot Mix Asphalt Mixture Incorporating Fibre

    Get PDF
    Permanent deformation is one of the distress that develops gradually as the number of load applications increases and appears as longitudinal depressions in the wheel paths and small upheavals to the sides. For this reason, numerous studies conducted on modification asphalt binder or mixture by various fibre. This paper presents the evaluation of creep modulus and permanent deformation of modified asphalt mixture with fibres. In order to envisage the modified asphalt mixture, Forta-fi, Kenaf and PET was blended to estimate the creep properties and rut depth value at different loading pattern. Superpave mix design method was employed with NMAS 12.5mm to obtain the optimum bitumen content established at 4% air void. In the respect, bitumen 60/70 penetration grade with 0.5% of Forta-Fi, 0.1% Kenaf fibre and 0.5% PET by weight of asphalt mixture were prepared. Dynamic Creep Test was performed in accordance to the EN 12697-25:2005 guidelines using the Universal Testing Machine (UTM). As the result, the minimum value of permanent deformation was found at 0.5% of PET. Based on these studies, adding a minimum percent of PET in the asphalt mixture shows a better resistance to rutting deformation and enable a better understanding of the properties in modified asphalt mixtures

    Perancangan dan Pembuatan Sistem Penebar Pakan Ikan Jenis Pasta Otomatis Berbasis Mikrokontroler At89s51

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    Indonesia is an agricultural country with abundant natural resources, including fishery. Fishermen are found almost throughout parts of Indonesia with different size pool or pond. Manually feeding is ineffective because of the number of fish's food used was not always fixed even if it takes a long time feeding evenly throughout the pool. Spreader tool forage fish species AT89S51 microcontroller-based pasta has been made to provide the feed of pasta with fixed volumes levelled DC motor based machine

    Rutting assessment of crumb rubber modifier modified warm mix asphalt incorporating warm asphalt additive

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    Warm Mix Asphalt (WMA) as a green technology, permits production of asphalt mixtures at lower temperatures compared to conventional HMA; emissions and energy consumption reduction, were among the key success of this technology, thus, enhancing social, economic, and environmental sustainability. But due to the reduced production temperature, WMA are more prone to rutting, to improve the rutting resistance of WMA mixtures and minimize pollution resulting from waste rubber tire. Therefore, the effect of wet processed Crumb Rubber Modifier (CRM) on rutting depth of WMA mixtures incorporating 2.5% Sasobit by weight of base binders were assessed in the laboratory. In this study, the asphalt mixtures were fabricated in accordance with Superpave, using; crush granite aggregate of 9.5mm NMAS and the four binders that were produced by blending the PG 64 binder with different contents of 40 mesh size CRM (0%, 5%, 10%, and 15%, by weight of the base binder). Rutting depths of the mixtures were assessed on 150mm diameter and 70mm thick cylindrical samples using wheel tracker, the wheel tracking test were carried out at 45oC and 60oC, in accordance with BS 598 Part 110 (1998). Based on the results of wheel tracking tests, CRM could improve the resistance of the WMA mixtures to rutting. It was also found from statistical Analysis of Variance (ANOVA), that the two influence factors; CRM, and the test temperature both having p-values less than the assumed significance at 95% confidence level, therefore they have significant effect on rutting in WMA

    Evaluation of Nigerian public housing performance using occupants’ experience and satisfaction

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    There is misconception of occupants’ satisfaction and experience in building performance evaluation due to inadequacy of in-depth studies on each, which resulted to insufficiency of facts about their structure, determinant variables, effects of socioeconomic attributes and conditions under which they are connected. Objective of the study were to identify the building performance levels and differences between occupants’ satisfaction and experience, effects of socioeconomic attributes on them and propose a framework to evaluate public housing performance using occupants’ satisfaction and experience. Building Use Studies (BUS) Methodology, UK questionnaire was adapted and used on a license agreement. Systematic random sampling was used to collect data from 300 occupants of four (4) public housing estates in Gombe metropolis Nigeria. Two independent factors of tangible and intangible building features were conceptualised. Exploratory factor analysis (EFA) was used in the pilot survey to identify the factorability of the variables. The Confirmatory factor analysis (CFA) in AMOS software was used to validate the constructs and develop two structural equation models (SEM) based on occupants satisfaction and experience. The models were subjected to multi CFA moderation method to determine the effects of socioeconomic attributes of the occupants. The results indicated differences in performance of features based on occupants’ satisfaction and experience. The SEM moderation results showed that education and income moderates occupants’ satisfaction, while they does not moderates occupants’ experience. Therefore, the study concluded with emphasis on the importance of occupants experience as an objective measure of building performance against occupants’ satisfaction’s subjectivity. Based on that, a framework to evaluate public housing performance using occupants’ satisfaction and experience was proposed

    Diagnosis of Infection After Splenectomy for Trauma Should be Based on Lack of Platelets Rather Than White Blood Cell Count

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    Background: There is a lack of evidence-based criteria to assist the diagnosis of infection following trauma splenectomy (TS). However, the literature suggests that white blood cell count (WBC) is associated with infection in patients who undergo TS. We sought to find whether there exist key differences in laboratory and clinical parameters that can assist the diagnosis of infection after TS. Methods: We evaluated all consecutive trauma patients who had undergone TS at a Level 1 trauma center from 2005 to 2011 for the development of infection. To do this, we compared the values of demographic, laboratory, and clinical variables of infected and non-infected patients on odd post-operative days (POD) in the period from 1–15 days after TS. Results: Of 127 patients who underwent TS, 25 died within 48 h after the procedure and were excluded from our analysis, leaving, 102 patients for investigation. In the 41 (40%) patients who developed an infection, the mean day for the first infectious episode was POD 7 (range, POD 4–14). The three most common infections were pneumonia (51%), urinary tract infection (24%), and bacteremia (20%). An evaluation of laboratory and clinical parameters showed no differences in the WBC of the patients who did and did not develop infections at any time in the 15 d after TS. However, the platelet count was statistically significantly higher in non-infected patients on POD 3–9 and on POD 13, and maximal body temperature was statistically significantly higher in the infected group of patients during the first week after TS. Differences in laboratory and clinical values of the infected and non-infected patients were greatest on POD 5. Conclusions: Patients who undergo TS have high rates of infectious complications. The WBC is not a reliable predictor of infection in these patients in the 2 wks following TS. However, patients who do not develop infection after TS have statistically significantly higher absolute platelet counts and rates of change in their daily platelet counts than those who develop infection
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