scholarly journals Analysis of the Influence of Production Method, Crumb Rubber Content and Stabilizer on the Performance of Asphalt Rubber

2020 ◽  
Vol 10 (16) ◽  
pp. 5447
Author(s):  
Haibin Li ◽  
Wenbo Li ◽  
Ahmed Abdulakeem Temitope ◽  
Dong Zhao ◽  
Guijuan Zhao ◽  
...  

Asphalt rubber (AR) is often described as an environmentally friendly material due to the incorporation of recycled rubber from used tires and its improved service life. Its field application is influenced by many factors. In order to evaluate the impact of different factors such as crumb rubber (CR) content, stabilizer and the production method on the performance of rubber powder modified asphalt, two different matrix asphalts were prepared, the basic experiments, control variable methods and several related tests were thereafter conducted. The results showed that a moderate amount of CR could enhance the pavement performance. The suitable CR content was 20–25% for 90# matrix asphalt and 22–26% for 70# matrix asphalt. The stabilizer had a positive impact on the AR’s high temperature behavior and was beneficial to the storage of AR, but it did not make a significant influence on low temperature behavior. In addition, different methods brought certain performance differences. Though AR produced with the heat fusion method had better high-temperature performance, the rubber particles would easily disperse and melt in the asphalt during the shearing process, which gave AR more balanced physical performance. This study identifies the shearing method as the optimal choice for site construction and provides a wider application range for asphalt rubber in the road construction field. The selection of parameters depends on the construction areas and performance requirements.

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1200 ◽  
Author(s):  
Cheng ◽  
Liu ◽  
Ren ◽  
Huang

Crumb rubber, as a recycled material used in asphalt mixture, has gained more attention in recent years due to environmental benefits and the advantages of its pavement, such as excellent resistance to cracking, improved durability, less road maintenance, lower road noise, etc. However, the high-temperature performance of mixture with crumb rubber does not perform well. In order to improve the performance, this paper examined the effect of additives on the laboratory performance of asphalt rubber Stone Matrix Asphalt (AR-SMA) with additives. Three groups of AR-SMA: no additives, Styrene–Butadiene–Styrene (SBS) and Granular Polymer Durable additive (GPDa) were included, with no additives as a control group. Each group was investigated at three asphalt rubber content (ARC): 6.4%, 6.9%, 7.4% with regard to high-temperature and fatigue properties. The results show that with increasing ARC, the high-temperature performance of mixture without additive decreases, and the high-temperature performance increases first and then decreases for SBS and GPDa. Moreover, the rutting resistance of AR-SMA with GPDa at 6.9% ARC performs best. Under the condition of mixtures with appropriate ARC, AR-SMA with GPDa has higher fatigue life and sensitivity to fatigue cracking than the control group. Simultaneously, the fatigue performance of AR-SMA with GPDa is not as significant as that without additive with increasing ARC. In a word, GPDa is a good choice to improve the performance of AR-SMA. However, it should be noted that optimal asphalt content of AR-SMA mixtures with GPDa is higher than that of traditional mixtures.


2001 ◽  
Vol 14 (3) ◽  
pp. 147-158 ◽  
Author(s):  
Robert Weech-Maldonado ◽  
Jacqueline E. Zinn ◽  
Robert D. Hamilton

This study develops a model and empirically assesses how# organizational context mediates the impact of total quality management (TQM) implementation on perceived performance in the nursing facility industry. Outcomes are analysed for financial, human resources and resident-care performance. Contextual factors related to TQM implementation include managerial control, reward systems, organizational structure and the extent of implementation. Duration of TQM implementation is included as a control variable. Benchmarking has a positive impact on financial outcomes, and the extent of TQM implementation and required reporting of quality improvement activity results have a positive impact on both financial and human resources performance. The presence of a Quality Steering Council has a positive impact on financial performance, but only among larger facilities.


2001 ◽  
Vol 14 (3) ◽  
pp. 147-158 ◽  
Author(s):  
Robert Weech-Maldonado ◽  
Jacqueline E. Zinn ◽  
Robert D. Hamilton

This study develops a model and empirically assesses how# organizational context mediates the impact of total quality management (TQM) implementation on perceived performance in the nursing facility industry. Outcomes are analysed for financial, human resources and resident-care performance. Contextual factors related to TQM implementation include managerial control, reward systems, organizational structure and the extent of implementation. Duration of TQM implementation is included as a control variable. Benchmarking has a positive impact on financial outcomes, and the extent of TQM implementation and required reporting of quality improvement activity results have a positive impact on both financial and human resources performance. The presence of a Quality Steering Council has a positive impact on financial performance, but only among larger facilities.


2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
Zechen Yao ◽  
Renfeng Yang ◽  
Jian Kang ◽  
Zhigang Zhang

In this paper, the applicability of the elastic recovery (resilience) experiment for asphalt-rubber (AR) binders has been quantitatively assessed. The mechanical model, based on the viscoelastic constitutive relation and particle inclusion theory, was developed. The interfacial detachment between crumb rubber (CR) particles and asphalt caused by stress concentration was analyzed with Weibull statistical equations. Based on the road roughness excitation, the vehicle-road coupling vibration model was established to analyze the impact of vehicle loading on road surface deformation. AR binders with different CR particle sizes were assessed using scanning electron microscope (SEM) imaging and prepared for testing the elastic recovery (resilience). The results showed that the greater internal stress caused by the longer stretch length of AR binders in the elastic recovery experiment was ten times higher than that obtained from the resilience experiment, leading to the interfacial detachment between asphalt and the CR particles. Hence, the elastic property of some of the CR particles with high modulus was not reflected, resulting in the test values being lower than actual values. With the reduction of CR particle size, the interfacial detachment was improved in the elastic recovery experiment due to intense material interchange and the enhancement of interfacial bond strength. The millimeter-scale compression deformation of the AR binder in the resilience experiment was closer to the actual deformation of the road surface. The experimental time of resilience (120 min) has been reported less than that for elastic recovery (200 min–230 min). This study shows that the resilience experiment has a significant advantage in assessing the elastic property of the AR binder.


VASA ◽  
2019 ◽  
Vol 48 (3) ◽  
pp. 262-269 ◽  
Author(s):  
Christian-Alexander Behrendt ◽  
Tilo Kölbel ◽  
Thea Schwaneberg ◽  
Holger Diener ◽  
Ralf Hohnhold ◽  
...  

Abstract. Background: Worldwide prevalence of peripheral artery disease (PAD) is increasing and peripheral vascular intervention (PVI) has become the primary invasive treatment. There is evidence that multidisciplinary team decision-making (MTD) has an impact on in-hospital outcomes. This study aims to depict practice patterns and time changes regarding MTD of different medical specialties. Methods: This is a retrospective cross-sectional study design. 20,748 invasive, percutaneous PVI of PAD conducted in the metropolitan area of Hamburg (Germany) were consecutively collected between January 2004 and December 2014. Results: MTD prior to PVI was associated with lower odds of early unsuccessful termination of the procedures (Odds Ratio 0.662, p < 0.001). The proportion of MTD decreased over the study period (30.9 % until 2009 vs. 16.6 % from 2010, p < 0.001) while rates of critical limb-threatening ischemia (34.5 % vs. 42.1 %), patients´ age (70 vs. 72 years), PVI below-the-knee (BTK) (13.2 % vs. 22.4 %), and rates of severe TASC C/D lesions BTK (43.2 % vs. 54.2 %) increased (all p < 0.001). Utilization of MTD was different between medical specialties with lowest frequency in procedures performed by internists when compared to other medical specialties (7.1 % vs. 25.7 %, p < 0.001). Conclusions: MTD prior to PVI is associated with technical success of the procedure. Nonetheless, rates of MTD prior to PVI are decreasing during the study period. Future studies should address the impact of multidisciplinary vascular teams on long-term outcomes.


2020 ◽  
pp. 23-40
Author(s):  
I. V. Prilepskiy

Based on cross-country panel regressions, the paper analyzes the impact of external currency exposures on monetary policy, exchange rate regime and capital controls. It is determined that positive net external position (which, e.g., is the case for Russia) is associated with a higher degree of monetary policy autonomy, i.e. the national key interest rate is less responsive to Fed/ECB policy and exchange rate fluctuations. Therefore, the risks of cross-country synchronization of financial cycles are reduced, while central banks are able to place a larger emphasis on their price stability mandates. Significant positive impact of net external currency exposure on exchange rate flexibility and financial account liberalization is only found in the context of static models. This is probably due to the two-way links between incentives for external assets/liabilities accumulation and these macroeconomic policy tools.


2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.


2018 ◽  
Vol 15 (1) ◽  
pp. 55-72
Author(s):  
Herlin Hamimi ◽  
Abdul Ghafar Ismail ◽  
Muhammad Hasbi Zaenal

Zakat is one of the five pillars of Islam which has a function of faith, social and economic functions. Muslims who can pay zakat are required to give at least 2.5 per cent of their wealth. The problem of poverty prevalent in disadvantaged regions because of the difficulty of access to information and communication led to a gap that is so high in wealth and resources. The instrument of zakat provides a paradigm in the achievement of equitable wealth distribution and healthy circulation. Zakat potentially offers a better life and improves the quality of human being. There is a human quality improvement not only in economic terms but also in spiritual terms such as improving religiousity. This study aims to examine the role of zakat to alleviate humanitarian issues in disadvantaged regions such as Sijunjung, one of zakat beneficiaries and impoverished areas in Indonesia. The researcher attempted a Cibest method to capture the impact of zakat beneficiaries before and after becoming a member of Zakat Community Development (ZCD) Program in material and spiritual value. The overall analysis shows that zakat has a positive impact on disadvantaged regions development and enhance the quality of life of the community. There is an improvement in the average of mustahik household incomes after becoming a member of ZCD Program. Cibest model demonstrates that material, spiritual, and absolute poverty index decreased by 10, 5, and 6 per cent. Meanwhile, the welfare index is increased by 21 per cent. These findings have significant implications for developing the quality of life in disadvantaged regions in Sijunjung. Therefore, zakat is one of the instruments to change the status of disadvantaged areas to be equivalent to other areas.


2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.


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