scholarly journals Resistance of Geosynthetics against the Isolated and Combined Effect of Mechanical Damage under Repeated Loading and Abrasion

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3558
Author(s):  
Filipe Almeida ◽  
David Miranda Carlos ◽  
José Ricardo Carneiro ◽  
Maria de Lurdes Lopes
Keyword(s):  
Hydraulic Properties ◽  
Construction Materials ◽  
Mechanical Damage ◽  
Tensile Tests ◽  
Repeated Loading ◽  
Short Term ◽  
Engineering Structures ◽  
Wide Range ◽  
Materials Used ◽  
Reduction Factors

The behaviour of materials used for developing engineering structures should be properly foreseen during the design phase. Regarding geosynthetics, which are construction materials used in a wide range of engineering structures, the installation on site and the action of many degradation agents during service life may promote changes in their properties, endangering the structures in which they are applied. The evaluation of the damage suffered by geosynthetics, like installation damage or abrasion, is often carried out through laboratory tests. This work studied the behaviour of five geosynthetics (three geotextiles and two geogrids) after being individually and successively exposed to two degradation tests: mechanical damage under repeated loading and abrasion. The short-term mechanical and hydraulic behaviours of the geosynthetics were analysed by performing tensile tests and water permeability normal to the plane tests. Reduction factors were determined based on the changes occurred in the tensile strength of the geosynthetics. Findings showed that mechanical damage under repeated loading and abrasion tended to affect the mechanical and hydraulic properties of the geosynthetics and that the reduction factors calculated according to the traditional method may not be able to represent accurately the damage suffered by the materials when exposed successively to the degradation mechanisms.

scholarly journals Effect of Different Aggregates on the Mechanical Damage Suffered by Geotextiles

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4229 ◽  
Author(s):  
David Miranda Carlos ◽  
José Ricardo Carneiro ◽  
Maria de Lurdes Lopes
Keyword(s):  
Water Permeability ◽  
Hydraulic Properties ◽  
Unit Area ◽  
Construction Materials ◽  
Mechanical Damage ◽  
Repeated Loading ◽  
Short Term ◽  
Loading Tests ◽  
Natural Aggregates ◽  
Useful Lifetime

The installation process of geosynthetics can be, in some applications, one of the most relevant degradation mechanisms of these construction materials, affecting their performance and useful lifetime. In this work, three nonwoven geotextiles with different masses per unit area were submitted to mechanical damage under repeated loading tests with corundum and with different natural aggregates. The damage occurred in the geotextiles was evaluated by visual inspection and by monitoring changes in their short-term tensile and puncture behaviors (mechanical properties) and in their water permeability behavior normal to the plane (hydraulic property). The mechanical damage under repeated loading tests provoked relevant changes in the mechanical and hydraulic properties of the geotextiles. These changes depended on the mass per unit area of the geotextiles and on the characteristics of the aggregates. The results enabled the establishment of a correlation between the loss of mechanical strength and the variation of the water permeability normal to the plane of the geotextiles.

scholarly journals Influence of Mechanical Damage under Repeated Loading on the Resistance of Geogrids against Abrasion

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3544
Author(s):  
David Miranda Carlos ◽  
Filipe Almeida ◽  
José Ricardo Carneiro ◽  
Maria de Lurdes Lopes
Keyword(s):  
Visual Inspection ◽  
Building Materials ◽  
Mechanical Damage ◽  
Tensile Tests ◽  
Strength Reduction ◽  
Soil Reinforcement ◽  
Repeated Loading ◽  
Negative Effect ◽  
Potential Negative Effect ◽  
Reduction Factors

Geogrids are building materials widely used for soil reinforcement that can be affected by the action of many degradation agents throughout their service life. The potential negative effect of the degradation agents should be properly estimated and accounted for during the design phase. The main aim of this work was to study the influence of mechanical damage under repeated loading on the resistance of geogrids against abrasion. Three geogrids (one extruded and two woven) were exposed in isolation to mechanical damage under repeated loading and abrasion tests, followed by the successive exposure to both degradation tests. The damage suffered by the geogrids was evaluated by visual inspection and by tensile tests. Based on the changes found in tensile strength, reduction factors were determined. The reduction factors obtained directly from the successive exposure were compared to those resulting from a method in which the reduction factors obtained for the isolated effect of each degradation agent were multiplied. Results indicated that the abrasion process tended to be affected by a previous exposure to mechanical damage under repeated loading and that the multiplication of the reduction factors obtained for the isolated effects of the degradation agents may not correctly represent their combined effect.

scholarly journals Use of Incinerator Bottom Ash as a Recycled Aggregate in Contact with Nonwoven Geotextiles: Evaluation of Mechanical Damage Upon Installation

2020 ◽  
Vol 12 (21) ◽  
pp. 9156
Author(s):  
Filipe Almeida ◽  
José Ricardo Carneiro ◽  
Maria de Lurdes Lopes
Keyword(s):  
Environmental Sustainability ◽  
Bottom Ash ◽  
Construction Materials ◽  
Mechanical Damage ◽  
Recycled Aggregate ◽  
Repeated Loading ◽  
Filling Material ◽  
Short Term ◽  
Loading Tests ◽  
Natural Aggregates

The recycling and reuse of materials is crucial to reducing the amount of generated waste and the exploitation of natural resources, contributing to achieving environmental sustainability. During the incineration process of municipal solid waste, a residue known as incinerator bottom ash is generated in considerable amounts, being important the development of solutions for its valorization. In this work, three nonwoven geotextiles were submitted to mechanical damage under repeated loading tests with incinerator bottom ash and, for comparison purposes, with three natural aggregates (sand 0/4, gravel 4/8 and tout-venant) and a standard aggregate (corundum). Damage assessment was carried out by monitoring the changes that occurred in the short-term tensile and puncture behaviors of the geotextiles. Results showed that the damage induced by incinerator bottom ash on the short-term mechanical behavior of the geotextiles tended to be lower than the damage induced by the natural aggregates or by the standard aggregate. Therefore, concerning the mechanical damage caused on geotextiles, there are good prospects for the use of incinerator bottom ash as a filling material in contact with those construction materials, thereby promoting its valorization.

scholarly journals Modern biopositive technologies of waste processing in the utilities and construction industries

Vestnik MGSU ◽  
2020 ◽  
pp. 1135-1146
Author(s):  
Konstantin L. Chertes ◽  
Nikolay I. Shestakov
Keyword(s):  
Asphalt Concrete ◽  
Waste Water Treatment ◽  
Construction Materials ◽  
Research Literature ◽  
Municipal Sewage ◽  
Waste Processing ◽  
Engineering Structures ◽  
Sedimentation Stability ◽  
Construction Waste ◽  
Wide Range

Introduction. In this article the analysis of certain biopositive technologies applied to processing or recycling of construction waste, municipal sewage, and paste-like slurries of organo-mineral nature is performed. The relevance of this research is confirmed by the steadily growing number of publications and currently implemented government programmes aimed at solving such problems. The paper summarizes the results of research into the treatment of wastes having different origin. Materials and methods. The analysis of the research literature and patents for inventions, as well as publicly available technologies used in waste processing and recycling is performed. Selection of biopositive technologies based on the chemical nature of materials and their groups is described. Biopositive technologies, most effectively applied to construction materials, are identified for the purpose of converting engineering structures into secondary raw components. The co-authors demonstrate the application of a biopositive technology to sludge decontaminated at municipal waste water treatment plants and to hot waste generated by the hydrolysis industry, as well as technologies used to process special thermal insulation and waterproofing materials. Results. The use of water-organic emulsions as active components in effective regeneration of asphalt granulated concrete mixtures is considered. Сompositions, concentrations and sedimentation stability of such emulsions have been identified. The results of the study of physical, mechanical and hydro-physical properties of the asphalt-concrete granulate treated with water-organic emulsions are described. This regeneration technology helps bitumen to restore binding properties on the surface of the asphalt-concrete granulate and makes this composite applicable as a material designated for the bottom layers of the road pavement. Conclusions. These biopositive technologies make it possible to efficiently and rationally process or recycle a wide range of municipal and construction waste into structures and products having various applications. Recycling, composting and plasma technologies are considered in this case.

scholarly journals Artificial and Natural Aging of Polypropylene Used in Passenger Vehicle Bumpers

2021 ◽  
Vol 58 (2) ◽  
pp. 201-210
Author(s):  
Hongshen Zhang ◽  
Hongfei Zheng
Keyword(s):  
Accelerated Aging ◽  
Natural Aging ◽  
Short Term ◽  
Uv Aging ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Wide Range ◽  
Aging Properties ◽  
Materials Used ◽  
The Impact

Polypropylene (PP) has a wide range of applications in the automobile bumpers due to its many excellent properties. Mechanical properties of PP for automobile bumpers are investigated through an artificial accelerated aging test. The aging rules after different years of normal use and the artificial accelerated aging test are analyzed. The correlation between natural and artificially accelerated aging is also explored. It provides a reference for the study of the aging properties of polymers for automotive applications. Results show that the UV aging test can effectively simulate changes in tensile and bending strengths after natural aging and can be used to evaluate the weathering resistance of PP materials used in automotive bumpers. The tensile and bending strengths of these materials remain good during aging, and elongation is sensitive to aging. The short-term artificial accelerated aging test does not exert a significant influence on the impact strength of materials, and artificial accelerated aging does not completely reproduce the aging process of the material.

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

scholarly journals Analysis of the Impact on the Mechanical Properties of Modification of Oligohydroxyethers in Organic Solvent Solution with Rubbers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski
Keyword(s):  
Mechanical Properties ◽  
Scientific Paper ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Molecular Weights ◽  
Wide Range ◽  
Strength Tests ◽  
Materials Used ◽  
Styrene Butadiene ◽  
The Impact

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.

AMS Dating of Potentially the Oldest Wooden Sculptures in Japan from a Shinto Shrine in Akita

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1221-1228
Author(s):  
Naoto Fukuyo ◽  
Yusuke Yokoyama ◽  
Yosuke Miyairi ◽  
Yusuke Igarashi
Keyword(s):  
Tree Rings ◽  
Age Determination ◽  
Construction Materials ◽  
Historical Documents ◽  
Matching Method ◽  
Historical Objects ◽  
Ams Dating ◽  
Akita Prefecture ◽  
Materials Used ◽  
Matching Techniques

ABSTRACTWe analyzed rare wooden Komainu found at Akagami Shrine in Akita prefecture, Japan. The formation of historical objects is often thoroughly recorded in documents, although the formation age of this particular Komainu sculpture is still unknown due to its antiquity. Thus, age determination exercises have been conducted using radiocarbon (14C)-wiggle-matching techniques. Although only a limited quantity was available for sampling, we have successfully measured 14C samples in the sculptures along with several sets of tree rings. We interpret the Komainu sculptures age considering the age of the trees and the result obtained from the wooden construction materials used for the Akagami shrine. The results obtained from Komainu show a range from 550 CE to 1020 CE, which is consistent with the dates of the shrine’s formation. Thus, the multiple 14C-wiggle-matching method can determine precise calendar ages of wood, as well as provide some supportive information for the periods when there are no reliable historical documents.

scholarly journals Design and characterization of concrete masonry parts and structural concrete using repurposed plastics as aggregate

2019 ◽  
Vol 28 (1) ◽  
pp. 81-88
Author(s):  
Miguel A. González-Montijo ◽  
Hildélix Soto-Toro ◽  
Cristian Rivera-Pérez ◽  
Silvia Esteves-Klomsingh ◽  
Oscar Marcelo Suárez
Keyword(s):  
Structural Strength ◽  
Construction Materials ◽  
Tensile Tests ◽  
Compression Tests ◽  
Conventional Concrete ◽  
Structural Capacity ◽  
Plastic Type ◽  
Concrete Mix ◽  
Scientists And Engineers

AbstractHistorically known for being one of the major pollutants in the world, the construction industry, always in constant advancement and development, is currently evolving towards more environmentally friendly technologies and methods. Scientists and engineers seek to develop and implement green alternatives to conventional construction materials. One of these alternatives is to introduce an abundant, hard to recycle, material that could serve as a partial aggregate replacement in masonry bricks or even in a more conventional concrete mixture. The present work studied the use of 3 different types of repurposed plastics with different constitutions and particle size distribution. Accordingly, several brick and concrete mix designs were developed to determine the practicality of using these plastics as partial aggregate replacements. After establishing proper working material ratios for each brick and concrete mix, compression tests as well as tensile tests for the concrete mixes helped determine the structural capacity of both applications. Presented results proved that structural strength can indeed be reached in a masonry unit, using up to a 43% in volume of plastic. Furthermore, a workable structural strength for concrete can be achieved at fourteen days of curing, using up to a 50% aggregate replacement. A straightforward cost assessment for brick production was produced as well as various empirical observations and recommendations concerning the feasibility of each repurposed plastic type examined.

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