scholarly journals Sustainable Use of Waste Polypropylene Fibres to Enhance the Abrasion and Skid Resistance of Two-Stage Concrete

2021 ◽  
Vol 13 (9) ◽  
pp. 5200
Author(s):  
Rayed Alyousef
Keyword(s):  
Abrasion Resistance ◽  
Research Work ◽  
Sustainable Use ◽  
Plain Concrete ◽  
Skid Resistance ◽  
Two Stage ◽  
Polypropylene Fibres ◽  
Conventional Concrete ◽  
Carpet Industry ◽  
Waste Polypropylene

Two-stage concrete (TSC), also known as prepacked aggregate concrete (PAC), differs from traditional concrete in terms of site application and manufacturing process. Although this type of concrete is not a replacement for conventional concrete applications, it is an ideal option for unusual and difficult placing conditions, especially for repairing existing concrete structures. In other words, this type of concrete is a newly developed concrete and made by placing and packing coarse aggregates and fibres in a designed formwork, then injecting a cement grout mixture into the free spaces between the aggregate particles using gravity or a pump device. For the mentioned system and others, concrete components used as floors or pavements must have an adequate degree of roughness during service life when exposed to skid and abrasion. Thus, this research work introduced a new concrete method (prepacked aggregates fibre-reinforced concrete—PAFRC) with high abrasion and skid resistance reinforced with waste polypropylene (PP) fibres from the carpet industry. The effects of PP fibres at 0–1% dosages on the mechanical properties, abrasion resistance, and skid resistance of PAFRC mixes were studied. The results revealed that the addition of PP fibres reduces the compressive strength of concrete mixtures. Nonetheless, the presence of PP fibres results in PAFRC mixes having higher tensile strength, abrasion resistance, and skid resistance than plain concrete. It was detected that in both grouting methods (gravity and pump), with the addition of PP fibre up to a specific dosage, the resistance against abrasion and skid was increased by about 26% compared to plain PAC mix. Additionally, the outcomes indicated that PAFRC is a promising material for applications such as pavements with high abrasion and skid resistance.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals REUSED TYRE POLYMER FIBRE FOR FIRE-SPALLING MITIGATION

2016 ◽  
Author(s):  
Shan-Shan Huang ◽  
Harris Angelakopoulos ◽  
Kypros Pilakoutas ◽  
Ian Burgess
Keyword(s):  
Fresh Concrete ◽  
High Strength ◽  
Plain Concrete ◽  
Superior Performance ◽  
Polymer Fibre ◽  
Explosive Spalling ◽  
Polypropylene Fibres ◽  
Shrinkage Cracking ◽  
Plastic Shrinkage ◽  
The Eu

<p>Polypropylene fibres (PPF) are used in concrete principally to reduce plastic shrinkage cracking, but also to prevent explosive spalling of concrete exposed to fire. In the EU alone, an estimated 75,000 tonnes of virgin PPF are used each year. At the same time an estimated 63,000 tonnes of polymer fibres are recovered from end-of-life tyres, which are agglomerated and too contaminated with rubber to find any alternative use; currently these are mainly disposed of by incineration. The authors have initiated a study on the feasibility of reusing tyre polymer fibres in fresh concrete to mitigate fire-induced spalling. If successful, this will permit replacement of the virgin PPF currently used with a reused product of equal or superior performance. A preliminary experimental investigation is presented in this paper. High-strength concrete cubes/slabs have been tested under thermo-mechanical loading. This study has shown promising results; the specimens with the tyre polymer fibres have shown lower vulnerability to spalling than those of plain concrete.</p>

scholarly journals Assessment of the Quality of Soil and Groundwater of the Agricultural Area of Sidi Yahya Region, Morocco

2020 ◽  
Vol 150 ◽  
pp. 01001
Author(s):  
M. Lahmar ◽  
N. El Khodrani ◽  
S. Omrania ◽  
H. Dakak ◽  
R. Moussadek ◽  
...  
Keyword(s):  
Water Table ◽  
Land Management ◽  
Research Work ◽  
Sustainable Use ◽  
Soil Samples ◽  
Agricultural Area ◽  
Soil Parameters ◽  
The Impact ◽  
Soil And Water

The Gharb plain is the largest agricultural area in Morocco. It is characterized by fertile soils and the availability of water either from surface or groundwater which allowed intensive agriculture. The aim of this research work is to study the impact of this land management on the quality of water and soil. The study was done for the irrigated perimeter of Sidi Yahya belonging to the province of Sidi Slimane, Gharb (Morocco). Depth of water table and water pH were measured in situ while water and soil samples were collected and brought to the laboratory for their physico-chemical analyses. Sampling of 33water wells and soil samples, from six different zones, was done between May and October 2018. Analysis of variance (ANOVA) was used to check if mean water and soil parameters differed between zones. The results showed that the minimal and maximal water table depth were 6 and 96 m, respectively. Also, slightly more than half of the wells (51.5%) were inadequate for irrigation since they were either highly or extremely saline. Furthermore, soils were poor to moderately poor in organic matter but very rich in potassium and the phosphorus content was highly variable. Based on the statistical analysis, it is clear that the six zones had significantly different means for CaCO3, pH, OM, and exchangeable sodium percentage. Soil degradation like pollution and salinization may occur in this region if poor quality water is used for irrigation and if land is mismanaged. This research work can be considered as a first step towards a program for monitoring the quality of soil and water for adapting the land management with the final objective of securing high productivity and sustainable use of soil and water resources.

FLEXURAL BEHAVIOR OF HIGH STRENGTH GEO-POLYMER CONCRETE BEAMS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Vankudothu Bhikshma ◽  
Kandiraju Promodkumar ◽  
Putta Panduranghiah
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Research Work ◽  
High Strength ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Polymer Concrete ◽  
Conventional Concrete ◽  
Granulated Blast Furnace Slag ◽  
Load Carrying

The demand for concrete is increasing day by day. As the consumption of cement is increased, environmental issues arise due to the release of CO2 during the manufacturing of cement. The objective of this research work is to produce a pollution free concrete with a combination of fly ash and GGBS (Ground granulated blast furnace slag) and without the use of cement. In this paper an attempt was made to study the mechanical properties of high strength geo-polymer concrete of grade M60 using GGBS, fly ash and micro silica. The testing program was planned for the mechanical properties of geo-polymer concrete and flexural behavior of corresponding beams. The experimental results indicated that the geo-polymer concrete M60 grade has a compressive strength of 70.45 MPa at the age of 28 days cured at ambient condition. Further, flexural strength and split tensile strengths for M60 grade high strength geo-polymer concrete at 28 days were observed to be 5.45 MPa and 3.63 MPa respectively. The modulus of elasticity was higher than the theoretical value proposed by IS 456-2000. It was also observed that the load carrying capacity of M60 grade high strength geo-polymer concrete found to be more than corresponding grade conventional concrete. The load-deflection, moment-curvature relationships were studied. The experimental results were encouraging to continue for further research in the area high strength geo-polymer concrete.

scholarly journals Voluntary appointment of independent directors: evidence from Taiwan

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mao-Feng Kao ◽  
Lynn Hodgkinson ◽  
Aziz Jaafar
Keyword(s):  
Corporate Governance ◽  
Least Squares ◽  
Research Work ◽  
Ordinary Least Squares ◽  
Independent Directors ◽  
Parameter Estimates ◽  
Two Stage ◽  
Data Set ◽  
Content Type ◽  
Two Stage Least Squares

Purpose Using a data set of Taiwanese listed firms from 2002 to 2015, this paper aims to examine the determinants to voluntarily appoint independent directors. Design/methodology/approach This study uses panel estimation to exploit both the cross-section and time-series nature of the data. Further, this paper uses Tobit regression, generalized linear model (GLM) in the additional analysis and the two-stage least squares to mitigate for a possible endogeneity issue. Findings The main findings show that Taiwanese firms with large board sizes tend to voluntarily appoint independent directors and firms that already have independent supervisors more willingly to accept additional independent directors onto the board. Furthermore, ownership concentration and institutional ownership are positively associated with the voluntary appointment of independent directors. On the contrary, firms controlled by family members are generally reluctant to voluntarily appoint independent directors. Research limitations/implications The findings are important for managers, shareholders, creditors and policymakers. In particular, when considering the determinants of the voluntary appointment of independent directors, the results indicate that independent supervisors, outside shareholders and institutional investors are significant factors in influencing effective internal and external corporate governance mechanisms. This research work focuses on the voluntary appointment of independent directors. It would be interesting to compare the effectiveness of voluntary appointments with a mandatory appointment within Taiwan and with other jurisdictions. Originality/value This study incrementally contributes to the corporate governance literature in several ways. First, this study extends the earlier research by using a more comprehensive data set of non-financial Taiwanese firms and using alternative methodologies to investigate the determinants of voluntary appointment of independent directors. Second, prior studies tend to neglect the possible issue of using a censored and fractional dependent variable, the proportion of independent directors, which might yield biased and inconsistent parameter estimates when using ordinary least squares regression estimation. Finally, this study addresses the relevant econometric issues by using the Tobit, GLM and the two-stage least squares for a possible endogeneity concern.

The Center for Sustainable Utilization of Resources: Quantifying Climate Change Impacts of Managing Wastes

2009 ◽  
Author(s):  
Maria Zannes ◽  
Morton Barlaz ◽  
Marco Castaldi ◽  
Nickolas J. Themelis
Keyword(s):  
North Carolina ◽  
Best Practices ◽  
Waste Management ◽  
Management Practices ◽  
Research Work ◽  
Sustainable Use ◽  
Climate Change Impacts ◽  
Past Research ◽  
Waste To Energy ◽  
Use Of Resources

The environmental impact and potential for utilization of the billions of tons of used products and materials discarded each year by humanity is immense. The sheer magnitude of the materials and complexity of waste management and reuse make the issue of quantifying impacts and best practices all the more difficult. In recognition of this task, the Earth Engineering Center (EEC) of Columbia University and the Environmental Engineering Group of North Carolina State University combined resources in 2008 to form a research organization that is focused on defining and promoting best practices for sustainable waste management. This is the Center for Sustainable Use of Resources (SUR; wwwSURcenter.org) and its mission is to quantify the greenhouse gas emissions and other life cycle impacts of various “waste” management practices; and use this information for advancing the best practical means for managing used materials, in the U.S. and globally. The SUR Center builds on the strengths of past research at Columbia and North Carolina State on recycling, composting, waste-to-energy, and landfilling. This paper describes some of the research work completed and underway at the Center.

An Approach to Sustainable Watershed Management

2017 ◽  
pp. 252-271
Author(s):  
Sneha Kumari ◽  
Yogesh Patil ◽  
Prakash Rao
Keyword(s):  
Water Management ◽  
Case Studies ◽  
Watershed Management ◽  
Water Distribution ◽  
Research Work ◽  
Sustainable Use ◽  
Secondary Data ◽  
Agricultural Crops ◽  
Water Requirements ◽  
The Village

Western Maharashtra consists of drought prone villages, which around seventy years ago were facing drastic challenges regarding water requirements. People living in such areas started to migrate from these villages in need of food and water. The chapter focuses on few case studies of drought prone areas of Western Maharashtra which made a move towards sustainability and has created an excellent model of watershed projects. Several practices like ban on cutting trees, terrace farming, contour bunding, drip irrigation, sprinkle irrigation, introduction of cooking stoves, rotational grazing, efficient water distribution and change in cultivation of agricultural crops according to the climate were followed which led the village to become a model for Aadarsh Gaon (An Ideal Village). The author has used secondary data from previous research work and critically analyses the case studies on water management in drought prone areas of Western Maharashtra which managed to become a model for sustainable use of water.

Achieving Climate Smart Agriculture with a Sustainable Use of Water

2017 ◽  
pp. 122-143 ◽  
Author(s):  
Sneha Kumari ◽  
Yogesh Patil
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Conceptual Framework ◽  
Management Strategies ◽  
Research Work ◽  
Sustainable Use ◽  
Agricultural Practices ◽  
Secondary Data ◽  
Zone Model ◽  
Smart Agriculture

With time there has been an unpredictable climate change affecting the requirement of water for agriculture. Survival of agriculture has become a matter of concern with an efficient management of water. The aim of the chapter is to design a conceptual framework in sustaining water for agriculture in the era of climate change. The authors in the present chapter have used secondary data from previous research work and critically analysed the cases on water management for agriculture. The chapter discusses on practices like drip irrigation, new adaptations, mitigation technologies, vapour pressure, agro-ecological zone model and other water management strategies and the agricultural practices which though increases the yield but is leaving an adverse impact on climate. The chapter designs a conceptual framework to sustain water for agricultural use in the era of climate change and discusses it. This must be dealt through in order to attain sustainability.

An Approach to Sustainable Watershed Management

2020 ◽  
pp. 286-305 ◽  
Author(s):  
Sneha Kumari ◽  
Yogesh Patil ◽  
Prakash Rao
Keyword(s):  
Water Management ◽  
Case Studies ◽  
Watershed Management ◽  
Water Distribution ◽  
Research Work ◽  
Sustainable Use ◽  
Secondary Data ◽  
Agricultural Crops ◽  
Water Requirements ◽  
The Village

Western Maharashtra consists of drought prone villages, which around seventy years ago were facing drastic challenges regarding water requirements. People living in such areas started to migrate from these villages in need of food and water. The chapter focuses on few case studies of drought prone areas of Western Maharashtra which made a move towards sustainability and has created an excellent model of watershed projects. Several practices like ban on cutting trees, terrace farming, contour bunding, drip irrigation, sprinkle irrigation, introduction of cooking stoves, rotational grazing, efficient water distribution and change in cultivation of agricultural crops according to the climate were followed which led the village to become a model for Aadarsh Gaon (An Ideal Village). The author has used secondary data from previous research work and critically analyses the case studies on water management in drought prone areas of Western Maharashtra which managed to become a model for sustainable use of water.

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