A new apparatus for determining the shrinkage limit of clay soils

A new apparatus for the determination of shrinkage limit is described. Two versions have been produced: a manually operated prototype ‘version1' followed by an automated version named SHRINKiT. Test results using the former for British and overseas clay soils are described and comparisons made with the British Standards preferred method. A further set of test results is described for SHRINKiT. However, it was not possible to compare these with the BS 1377 method owing to the introduction of a ban on the use of mercury in the British Geological Survey's geotechnical laboratories. The new method is set in the context of the huge cost of shrink/swell-related subsidence damage in Britain and the relative disuse of both BS 1377 methods for shrinkage limit, for reasons of safety. The shrinkage behaviour of different soils types and sample states is discussed, in addition to the advantages and disadvantages of the new method

Release of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Rubber Crumb in Synthetic Turf Fields: Preliminary Hazard Assessment for Athletes

Synthetic turf, made with an infill of rubber crumb from used tyres or virgin rubber, is now common in many sporting facilities. It is known that it contains compounds such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals. We evaluated in nine samples of rubber crumb the total content of some heavy metals (Zn, Cd, Pb, Cu, Cr, Ni, Fe) normally found in tyres by microwave mineralization and the levels of the 14 US EPA priority PAHs by Soxhlet extraction and HPLC analysis. The results showed high levels of PAHs and zinc in all rubber crumb samples compared to rubber granulate limits set by Italian National Amateur League (LND). Following the precautionary principle, a risk assessment at 25°C was done, using the Average Daily Dose (ADD) assumed by athletes, expressed in terms of mass of contaminant per unit of body weight per day (mg/kg day), and the Lifetime Average Daily Dose (LADD) and then evaluating the Hazard Index (HI) and the Cumulative Excess Cancer Risk (∑ECR). In the different rubber granulates samples the HI ranges from a minimum of 8.94×10-7 to a maximum of 1.16×10-6, while the ∑ECR ranges from a minimum of 4.91×10-9 to a maximum of 1.10×10-8. Finally, the aim of this study was to estimate the “hazard” for athletes inhaling PAHs released at the high temperatures this synthetic turf may reach. Then a sequence of proofs was carried out at 60°C, a temperature that this rubber crumb can easily reach in sporting installations, to see whether PAH release occurs. The toxicity equivalent (TEQ) of eva

Elastomeric shockpads for outdoor synthetic sport pitches

This thesis identified key mix design variables that influence the mechanical properties and behaviour of shockpads and developed a mechanical model to describe this behaviour. This investigation was undertaken to address the lack of scientific understanding of shockpad layers used in synthetic sports pitches. Shockpads play a crucial role in the player and ball interaction properties of synthetic pitches. However, the current poor state of knowledge regarding shockpad mix design effects and the implications for site practice during construction was developed through constructor experience and basic testing. This lack of comprehensive knowledge was reflected in the barelyexistent standards for design specification and testing requirements stipulated by sporting governing bodies at the time of this project inception. Further scientific investigation of the effects of shockpad mix design on mechanical properties and behaviour was required to develop guidelines to optimise shockpad design, construction and testing and also to build more knowledge on sport surface behaviour due to growing interest among the industry and other stakeholders such as governing bodies and sport shoe manufacturers for example. A method to construct small-scale cast in-situ shockpads in the laboratory was developed to produce reliable and repeatable samples for investigation, including a benchmark shockpad and shockpads with carefully controlled mix design variations. Shockpad thickness, binder content, binder type, rubber size, rubber size distribution and bulk density were varied through a range of appropriate values in the laboratory constructed shockpads. Shockpads and shockpad-carpet systems (using water based and 3'1 generation carpets) were subjected to Berlin Artificial Athlete and 2.25 kg Clegg Hammer impacts to measure player-surface interaction properties and vertical hockey ball impacts to measure ball interaction properties. Tensile measurements and cyclic fatigue testing were used to determine shockpad durability. Impact testing was repeated on shockpads and shockpad-carpet systems with thickness variations to determine shockpad behaviour using a force plate. Behaviour measurements were used to develop a mechanical model to describe shockpad behaviour. (Continues...).EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Sustainability and the next industrial revolution: A Revolutionary approach

The concept of the Next Industrial Revolution is relatively new. Information regarding this topic is not mainstream. There is little literature on how design, and the scientific principles, outlined in the Natural Step, are interconnected within the concept of the Next Industrial Revolution. In this thesis, I explore the big picture of where companies are today regarding sustainability issues, and how some companies are taking the lead in participating in this revolutionary new idea of the Next Industrial Revolution. How are these companies different? What are the similarities? Why and when do some companies choose to take revolutionary approaches, while others progress in an evolutionary fashion? These are the questions I have attempted to answer. Through casestudies, this thesis identifies who is preparing for the Next Industrial Revolution, what steps are being taken in preparation, what tools are needed, and how well the companies are progressing towards their goals. The casestudies highlight challenges companies experience in defining and reaching the goal of sustainable development. This approach also includes companies that are not implementing strategies and/or the tool of the Next Industrial Revolution, and attempts to explain the issues surrounding their decision to not take this path

Use Of Crumb Rubber To Improve Thermal Efficiency Of Construction Materials

Motivated by the tremendous trend toward green environment and to reduce the effect of scrap tires on the environment, this research is an attempt to find a practical and environmentally sound solution of the problem of scrap tires. A few literatures are available about the effect of crumb rubber on thermal conductivity (k-value) of mortar. Furthermore, almost there is no studies have considered the effect of crumb rubber on the thermal properties of gypsum materials. For this purpose, an experimental program was established to investigate the amount and size of crumb rubber (rubber obtained from recycling scrap tires) on the thermal properties of mortar and gypsum. Four levels of sand replaced with crumb rubber 10%, 20%, 30%, and 40% and three sizes of crumb rubber (#30, #10_20 and combination of both sizes) considered to make twelve rubberized mortar and eight rubberized gypsum specimens. The specimens tested for thermal conductivity using an apparatus constructed for this purpose. Water absorption and unit weight of rubberized mortar were tested. It was found that the size and the amount of crumb rubber had an effect on thermal properties of the specimens investigated. k-value decreased when amount of rubber increased. Thermal conductivity of rubberized mortar was13 – 28% lower than the ordinary mortar and rubberized gypsum was18 – 38% lower than the ordinary gypsum. The water absorption of mortar mixtures contained up to 20% of crumb rubber inclusion was lower than that of plain mortar. In regard of rubber particle size, courser rubber particles gave higher reduction in k-value if compared to finer size. The materials investigated in this research can be used as coating material to improve thermal insulation property of exterior walls.Two equations to predict k-value of mortar and gypsum consist of crumb rubber were proposed. Finally, finite element approach to convert amount of rubber used in each mixture to a layer of rubber was used to develop equations to estimate the k-value of mortar and gypsum containing crumb rubber

Dynamic Behaviour of High Performance of Sand Surfaces Used in the Sports Industry

The sand surface is considered a critical injury and performance contributing factor in different sports, from beach volleyball to greyhound racing. However, there is still a significant gap in understanding the dynamic behaviour of sport sand surfaces, particularly their vibration behaviour under impact loads. The purpose of this research was to introduce different measurement techniques to the study of sports sand surface dynamic behaviour. This study utilised an experimental drop test, accelerometry, in-situ moisture content and firmness data, to investigate the possible correlation between the sand surface and injuries. The analysis is underpinned by data gathered from greyhound racing and discussed where relevant.</jats:p

Superpave Mix Design and Laboratory Testing of Reacted and Activated Rubber Modified Asphalt Mixtures

abstract: Crumb rubber use in asphalt mixtures using wet process technology has been in practice for years in the United States with good performance history; however, it has some drawbacks that include the need for special blending equipment, high rubber-binder temperatures, and longer waiting time at mixing plants. Pre-treated crumb rubber technologies are emerging as a new method to produce asphalt rubber mixtures in the field. A new crumb rubber modifier known as Reacted and Activated Rubber (RAR) is one such technology. RAR (industrially known as “RARX”) acts like an Enhanced Elastomeric Asphalt Extender to improve the engineering properties of the binder and mixtures. It is intended to be used in a dry mixing process with the purpose of simplifying mixing at the asphalt plant. The objective of this research study was first to perform a Superpave mix design for determination of optimum asphalt content with 35% RAR by weight of binder; and secondly, analyse the performance of RAR modified mixtures prepared using the dry process against Crumb Rubber Modified (CRM) mixtures prepared using the wet process by conducting various laboratory tests. Performance Grade (PG) 64-22 binder was used to fabricate RAR and CRM mixtures and Performance Grade (PG) 70-10 was used to fabricate Control mixtures for this study. Laboratory tests included: Dynamic Modulus Test, Flow Number Test, Tensile Strength Ratio, Axial Cyclic Fatigue Test and C* Fracture Test. Observations from test results indicated that RAR mixes prepared through the dry process had excellent fatigue life, moisture resistance and cracking resistance compared to the other mixtures.Dissertation/ThesisMasters Thesis Civil, Environmental and Sustainable Engineering 201

Proc Inst Mech Eng H

Traumatic brain injuries are among the most common severely disabling injuries in the United States. Construction helmets are considered essential personal protective equipment for reducing traumatic brain injury risks at work sites. In this study, we proposed a practical finite element modeling approach that would be suitable for engineers to optimize construction helmet design. The finite element model includes all essential anatomical structures of a human head (i.e. skin, scalp, skull, cerebrospinal fluid, brain, medulla, spinal cord, cervical vertebrae, and discs) and all major engineering components of a construction helmet (i.e. shell and suspension system). The head finite element model has been calibrated using the experimental data in the literature. It is technically difficult to precisely account for the effects of the neck and body mass on the dynamic responses, because the finite element model does not include the entire human body. An approximation approach has been developed to account for the effects of the neck and body mass on the dynamic responses of the head-brain. Using the proposed model, we have calculated the responses of the head-brain during a top impact when wearing a construction helmet. The proposed modeling approach would provide a tool to improve the helmet design on a biomechanical basis.CC999999/Intramural CDC HHS/United States2017-02-14T00:00:00Z28097935PMC530888