Testing of Materials and Elements in Civil Engineering

This book was proposed and organized as a means to present recent developments in the field of testing of materials and elements in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of testing of different materials and elements in civil engineering, from building materials to building structures. The current trend in the development of testing of materials and elements in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained

Frictional Behaviour of Reinforcement in Reinforced Earth Fill Materials

This thesis reports on an investigation into the interaction between reinforcement and fill in reinforced earth. The theory and development of reinforced earth and previous research work pertaining to soil-reinforcement bond resistance have been reviewed. This investigation was mainly carried out using three different test methods, viz. large shear box tests, laboratory pull-out tests and field full-scale pull-out tests. Three types of reinforcing straps, viz. galvanized ribbed steel, Paralink 500s and Paralink 300s were tested with five different fill materials, viz. Wardley minestone, Wearmouth minestone, Horden red shale, Loudon Hill sand and Methil PFA. The tests were carried out under various conditions of overburden pressure, density, moisture content and strap length. A total of 550 tests were completed and the results obtained from the different test methods, different reinforcing and fill materials and various conditions are compared. The fill-reinforcement friction coefficient was found to be influenced by test method, overburden pressure, density, moisture content, strap length, extensibility and compressibility. Comparing the three test methods, no matter which reinforcement and fill material were used the field full-scale pull-out test produced the lowest friction coefficient. Higher results were generally obtained from laboratory pull-out tests than from direct shear box tests when ribbed steel was used, whereas when Paralink straps were used higher results were encountered from direct shear box tests. Ribbed steel strap produced the highest friction coefficient with Paralink 500s being superior to Paralink 300s, no matter which fill material was used. As regards fill materials, Horden red shale appeared to produce higher bond resistance, while the efficiency of the minestones, the PFA and the Loudon Hill sand varies with the type of reinforcement and test method. The pulling behaviour of Paralink straps in a pull-out test was monitored by using a "piano wire" method. The extensible Paralink straps were found to perform differently from rigid straps. The "piano wire" monitoring method is a readily available method to investigate the pulling behaviour of an extensible strap, strain distribution along a strap being calculated from the results. The strap extensibility is an important characteristic which causes the reduction of the apparent friction coefficient. It is believed that dilatancy and arching play an important part in a pull-out test. However, the arching effect acts differently with rigid ribbed steel and compressible Paralink straps. It increases the normal pressure on a ribbed steel strap, whereas when a Paralink strap is used the normal pressure is reduced. When Paralink straps are used, pull-out tests appear to be more suitable than shear box tests to obtain the fill-reinforcement friction coefficient, since the influence of extensibility and compressibility of a strap is involved in the former tests. A relationship was established between the friction coefficient and the overburden pressure and density for the present used materials

CLT-Steel Composite Floors for Sustainable Multi-Storey Construction

This thesis encompasses the investigation of a novel proposed construction system that pairs Cross-Laminated Timber (CLT) floor panels with steel-frame multi-storey construction. As a substitute for concrete floors, the promise of CLT lies in its reduced embodied carbon, and its lightness, which gives the promise of reduced material usage and a reduction in the environmental impact of a multi-storey building overall. In addition to clarifying the environmental benefit such a system provides, this thesis seeks to determine whether forming composite sections from the CLT panels and the steel beam, can lead to meaningful enhancements to the section stiffness in bending. Finite element analysis is applied for this task, necessitating first a methodology for modelling CLT to capture its relevant complexities as a material, and subsequently incorporation of the behaviour of the joints between structural elements in the proposed system, with the key characteristics of the materials and joint models validated against physical test data. Focusing predominantly on a slimfloor arrangement of panels and beams, the study provides the first evaluation of the effective width of CLT floor panels when acting compositely with steel beams, provides a prediction for composite action CLT panels and Asymmetric Steel Beams (ASBs) with a series of connectors, and identifies areas of development within the system that could bring about increased composite benefits. The outcomes of the study are that in a slimfloor arrangement with contemporary panels, beams and connectors, the composite enhancement is small but measurable, and that with changes and development to the system components, much larger composite enhancement effects could be generated

L'effet des différentes combinaisons d'adjuvants chimiques et liants sur la maniabilité des bétons autoplaçants à haute performance destinés aux réparations

Il est bien connu que l’hiver québécois est particulièrement agressif pour les ouvrages en béton. Les organismes publics doivent de plus en plus compter avec des travaux de réfection afin de réparer les structures existantes pour en prolonger la durée de vie. Le but de cette recherche est de développer un béton autoplaçant destiné aux travaux de réparation qui puisse faciliter la construction d’ouvrages minces et fortement renforcés. Cinq différents adjuvants et quatre différents liants hydrauliques ont été utilisés pour la fabrication d’un tel béton autoplaçant. Deux différentes approches ont été utilisées : l’une avec un faible rapport eau/liant sans agent colloïdal et l’autre avec un rapport eau/liant modéré avec agent colloïdal. La stabilité dynamique, la stabilité statique et les paramètres rhéologiques ont été mesurés lors des différents essais. Les propriétés du béton autoplaçant incluaient un étalement de 660 ± 20 mm et une stabilité statique limitée à une valeur maximale de 0,5%, mesurée avec une colonne de tassement de 700 mm. Des fibres ont été incorporées au béton autoplaçant et ses propriétés ont été améliorées jusqu’à un étalement de 700 ± 20 mm.Abstract : It is well known that the winter in Quebec is particularly harsh and poses high demand on concrete performance, especially that used in infrastructure applications. Government agencies, in charge of repair and rehabilitation of such infrastructure, must work to restore the concrete and to extend the lifetime of structures. The objective of this research is to develop high-performance, self-consolidating concrete intended for repair applications that will facilitate the casting of slim and highly reinforced sections while ensuring adequate durability and service life. The performance of fresh concrete made with several Chemical admixture and hydraulic binder combinations has been evaluated. In total, five different brands of admixtures along with four binder types were used in this investigation. Two different approaches were used in proportioning the concrete to ensure proper stability: the use of low water-cementitious ratio, or the use of a moderate water-cementitious ratio (w/cm) with a Viscosity-Enhancing Agent (VEA) to enhance cohesiveness. Optimized mixtures were assessed for key workability characteristics, including: static stability, dynamic stability, and rheological parameters. The mixtures had initial slump flow of 660 ± 20 mm and maximum surface settlement of 0.5%. Some mixtures were made with synthetic fibres and initial slump flow of 700 ± 20 mm

Design and performance of precast concrete structures

A precast concrete structural system offers many advantages over in-situ casting. For example, greater control over the quality of materials and workmanship, improved health and safety (with casting carried out at ground level rather than at height) and cost efficiency (with standard forms continually re-used) are all realised through the off-site production of structural elements. As a result, a large body of research has been conducted into their performance, with many national codes of practice also devoting specific sections to design and detailing. However, contemporary design practice has been shown to not always correctly reflect the findings of published experimental studies. Concrete technology is continually evolving, as is the industry s knowledge of how to model and predict the behaviour of the resulting structural components. Using such understanding to design and justify the more efficient, cost-effective or flexible manufacture of precast components can offer a key commercial advantage to a precast manufacturer. In this context, the numerical and experimental investigations undertaken as part of this study have been specifically focussed on quantifying the advantages of utilising beneficial alternatives. Specifically the research has looked at improvements in concrete mixes, lightweight aggregates and reinforcing strategies, for precast structural elements required to transfer loads both vertically and horizontally. However, because of the non-standard solutions considered, different approaches have been used to demonstrate their suitability. Towards this goal, an alternative assessment strategy was devised for slender precast concrete panels with central reinforcement. The procedure was found to lead to design capacities that are in good agreement with actual experimental findings and should thus result in future manufacturing efficiency. The method can also be used for alternative concrete types and reinforcement layouts. Fresh and early-age material characteristics of self-compacting concrete mixes with a partial or complete replacement of traditional gravel and sand constituents with lightweight alternatives were investigated. This was done to demonstrate the feasibility of their use for the manufacture of large scale structural components, with clear benefits in terms of lifting and transportation. A computational push-down procedure was utilised to demonstrate the potential unsuitability of current tying regulations for avoiding a progressive collapse event in precast framed structures. The findings are considered to be of particular significance for these structures due to the segmental nature of the construction and the associated inherent lack of structural continuity

A Numerical Study of a geosynthetic reinforced road embankment using nature-based basalt geogrid

Sammendrag I geoteknikk er det utfordrende å bygge veier og andre konstruksjoner på naturlig myk jord. Deformasjonsvansker oppstår ofte på fyllinger og fører til kollaps. Resultater av dette er enten en betydelig setning eller utglidning på grunn av utilstrekkelig skjærstyrke av bløt jord. Følgelig kan en deterministisk designtilnærming for å forsterke veifyllinger gjennom bruk av natur og unaturlig basert materiale i geosyntetisk geonett løse problemet. Miljøendringer som skjer over hele kloden, er muligens en faktor forbundet med økt risiko når det kommer til skred og bevegelse av store mengder jord og stein. En utfordring vi møter som er nødvendig å overkomme er å redusere bruken av uvennlig materiale. Denne forskningen prøver å finne miljøvennlig materiale som senere kan brukes til å erstatte uvennlig materiale i bygge bransjen. Dette krever en dypere forståelse og karakterisering av de naturbaserte materialene som vanligvis brukes i geosyntetiske geonett-forsterkede prosesser. Denne forskningen tar sikte på å overvinne utfordringene nevnt ovenfor ved å lage et geosyntetisk geonett ved å bruke naturbaserte materialer for å forsterke en veifylling. Sammenligning av resultatene av naturbaserte og polymerbaserte materialer som brukes i det geosyntetiske geonettet er hovedfokus. Hensikten er å bestemme hvor mye styrking som gis av naturbasert geonett for å strukturere og inkludere den kunnskapen i designtilnærmingen. Denne forskningen brukte PLAXIS 2D plane strain v8.6 med Mohr-Coulomb-modellen for å analysere stabiliteten til veifyllingshellingene mens det ble brukt basaltfiber og polymerbasert materiale i geosyntetisk geonett. Prosjektet tar sikte på å undersøke aktuelle teknikker for å forsterke fyllingsskråninger, begrunne bruk av geonett basert på basaltfiber for å forsterke voll, og bestemme den optimale posisjonen til laget i fyllingen. Resultatene viser at basaltmateriale bør brukes som alternativt materiale i geosyntetisk geonett. Det gir mer motstand mot deformasjon i vegfylling. Denne oppgaven konkluderer med bemerkningen at naturbasert geonett gir 32 % større forsterkning til veifyllingshellinger i stedet for forsterket polymerbasert geonett gjennom sammenligning av tre typer veifyllingshellinger.Abstract It is challenging to construct roads and other structures on naturally soft soil in geotechnical engineering. Deformation difficulties frequently occur on embankments and lead to collapse. This is either a significant settlement or sliding due to insufficient shear strength of soft soil. Deterministic design of reinforced road embankments employing natural and uncultivated materials in geosynthetic geogrid may address the problem. Environmental changings occurring across the globe are possibly a factor associated with increased risk when it comes to landslides and the movement of large amounts of soil and rock. A challenge we meet that is necessary to overcome is to reduce the usage of unfriendly material. This research tries to find environment-friendly materials which can later be used to replace unfriendly materials in the construction industry. This requires a deeper understanding and characterization of the nature-based materials which are commonly used in the geosynthetic geogrid-reinforced processes. This research aims to overcome the challenges mentioned above by creating a geosynthetic geogrid using nature-based materials to reinforce a road embankment. A comparison of the results of nature-based and polymer-based materials which are used in the geosynthetic geogrid is the focus. Its purpose is to determine how much strengthening is provided by nature-based geogrid to structure and include that knowledge into the design approach. This research use PLAXIS 2D plane strain v8.6 with the Mohr-Coulomb model for analyzing the stability of road embankment slope while using basalt fiber and polymer-based material in geosynthetic geogrid. The project aims to examine current techniques for strengthening embankment slopes, justify using geogrid based on basalt fiber for reinforcing embankments, and determine the optimal position of the layer in the embankment. The results show that basalt material should be used as an alternative material in geosynthetic geogrid. It gives more resistance to deformation in road embankments. This thesis concludes with the remark that nature-based geogrid provides more than 32 % significant reinforcement to road embankment slopes rather than reinforced polymer-based geogrid throughout a comparison of three types of road embankment slopes

Seismic analysis of a masonry arch bridge using multiple methodologies

Masonry arch bridges form a noteworthy portion of road and railway networks in Europe and Turkey. Structural assessment of such bridges is often required because of their vulnerability to seismic actions. However, there are no standardized or widely accepted procedures, and the available assessment methods comprise significant uncertainties. This paper presents a seismic assessment of a stone masonry arch bridge using different methodologies by investigating the seismic behavior of masonry arch bridges and the uncertainties in the assessment methods presented. The Finite Element (FE) macro-modeling approach is used in modeling the behavior of the structure under investigation, after undertaking ambient vibration testing and dynamic identification study to determine the dynamic parameters of the structure. These experimental parameters were used to update the FE model before performing the seismic assessment using Nonlinear Static Analysis (NSA), Nonlinear Dynamic Analysis (NDA) and Incremental Dynamic Analysis (IDA). The IDA helped to depict the complete picture of the seismic behavior, whereas the comparison of the results highlighted the limitations of the NSA and enabled presenting recommendations for future work. In addition, the effects of the interaction of horizontal and vertical components of earthquake records in NDA underlined the necessity for their consideration in similar studies.Peer ReviewedObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.b - Per a 2020, augmentar substancialment el nombre de ciutats i assentaments humans que adopten i posen en marxa polítiques i plans integrats per promoure la inclusió, l’ús eficient dels recursos, la mitigació del canvi climàtic i l’adaptació a aquest, així com la resiliència davant dels desastres, i desenvolupar i posar en pràctica una gestió integral dels riscos de desastre a tots els nivells, d’acord amb el Marc de Sendai per a la reducció del risc de desastres 2015.2030Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesPostprint (author's final draft

Rhéologie de matériaux à base de ciment utilisés pour l'impression 3D à grande échelle

Abstract : Concrete 3D printing introduces a brand-new technic of concrete elements production. The advantages of this technic over the conventional formwork-based method are (1) easier and less costly production of the elements with complex geometry, (2) a higher level of customization, (3) lower concrete and formwork materials waste, and (4) lower rate of manpower injuries. However, there are still several challenges toward the industrialization of concrete 3D printing, one of which is materials engineering. The main objective of this study is to develop cementitious materials that fulfill the two important requirements of the large-scale 3D printing process namely extrudability and buildability. Additionally, this study aims to develop suitable testing methods to refine the optimized cement-based materials subjected to 3D printing. The development of novel test methods to evaluate the rheology of the 3D printing materials is necessary to overcome the inadaptability of the existing testing methods. Indeed, the 3D printing mixtures exhibit a behavior described as extrudable yet stable in shape, thus require customized and adapted test methods to quantify their properties. In addition, the interaction between the material and the robot (3D printer) must be considered. To address this matter, cement-based materials with adapted thixotropic behavior were developed using chemical and mineral additives. Indeed, these materials greatly contribute to solving the problems of extrudability and shape stability of printing materials which have proven to be a major challenge in the case of the material-robot interaction. This study was conducted in 4 different and complementary phases. Phase 1 involved a comprehensive literature review and scanning the major problematics in the field regarding the materials engineering. In addition, a buy-or-make decision analysis was conducted in this phase to evaluate various alternatives to develop a large-scale concrete 3D printer at the Université de Sherbrooke. Several options were considered, and a decision was made to design and conceptualize a cartesian 4-axis gantry robot for in-house fabrication. In the Phase 2, the effectiveness of the rheometric methods to evaluate the structural build-up of printing materials was investigated. For this purpose, empirical testing methods such as mini-slump cone as well as rheometric methods were evaluated. In the case of rheological properties, the modified Bingham model parameters were identified for a wide array of materials and used for optimization. The structural build-up of mixtures was consequently measured using the evolution of the static yield stress and dynamic rheological measurements. Various mortar mixtures were subjected to 3D printing trials using a custom-made printer to evaluate the effectiveness of rheometric and empirical methods in assessing the extrudability and shape stability of the optimized mixtures. In Phase 3, cement-based materials with adapted thixotropic behavior were developed using chemical and mineral admixtures. Several mixtures were subsequently investigated to optimize 4 mixtures based on a structural build-up rate criterion. A feasibility study was also conducted at this point to adapt a compressive testing set-up for fresh cement-based materials. For this purpose, a prototype testing device was fabricated. In the next step and after tuning the prototype, a uniaxial compression device was fabricated with unique features including programmable force application protocols, deformation monitoring accuracy of 1 micron, mobility (the system requires solely a compressed air unit), and user-friendly interface. Furthermore, the uniaxial compression test was used to develop a testing method to quantify the fresh properties of mixtures. This contributed to overcoming the existing challenges of the rheometric testing methods when measuring the properties of mixtures with excessive rigidity. Initially, rotational rheometric methods to assess the static yield stress were used to characterize the investigated mortar mixtures. Secondly, the squeeze flow test was used to obtain the compressional yield stress using the fabricated device. Finally, in Phase 4, the in-house-made 3D printer at Université de Sherbrooke fabricated in parallel to the activities of this study was used to perform large-scale 3D printing and to validate the performance of the testing methods and the optimized mixtures in terms of extrudability and buildability. In addition, the effect of pumping and extrusion on the shear history of the materials was investigated to help adapting the thixotropic responses of mixtures to the 3D printing process. The performance of the developed compressive testing machine was validated through obtaining the structural build-up of the mortars and experimental simulation of the 3D printing process. In addition, a numerical investigation was carried out to simulate the process-induced shape variations of cement-based 3D printing materials.L'impression 3D béton introduit une toute nouvelle technique de production d'éléments en béton. Les avantages de cette technique par rapport à la méthode de construction conventionnelle basée sur l’utilisation de coffrage sont (1) une production plus facile et moins coûteuse des éléments à géométrie complexe, (2) un niveau de personnalisation plus élevé, (3) moins de déchets de béton et de matériaux de coffrage, et (4 ) un faible risque de blessure de la main-d'œuvre. Cependant, il existe encore plusieurs défis vers l'industrialisation de l'impression 3D du béton, notamment l'ingénierie des matériaux. L'objectif principal de cette étude est de développer des matériaux cimentaires qui répondent aux deux exigences importantes du processus d'impression 3D à grande échelle, à savoir l'extrudabilité et la constructibilité. De plus, l'étude vise à développer des méthodes d'essai appropriées pour affiner les matériaux à base de ciment optimisés soumis à l'impression 3D. Le développement de nouvelles méthodes d’essais pour évaluer la rhéologie des matériaux d'impression 3D est nécessaire pour surmonter l'inadaptabilité des méthodes existantes. En effet, les matériaux imprimables doivent être extrudables (i.e. pompable), mais de forme stable, nécessitent donc des méthodes d’essais personnalisées et adaptées pour quantifier leurs propriétés. De plus, l'interaction entre le matériau et le robot (imprimante 3D) doit être prise en compte. Pour répondre à ce problème, des matériaux cimentaires ayant un comportement thixotropique adapté ont été développés à l'aide des adjuvants et additions minérales. En effet, ces matériaux contribuent grandement à résoudre les problèmes d'extrudabilité et de stabilité de forme des matériaux d'impression, qui se sont avérés être un défi majeur dans le cas de l'interaction matériau-robot. Cette étude est réalisée en quatre différentes phases complémentaires. La Phase 1 comporte une revue de littérature complète et une analyse des principales problématiques dans le domaine d’impression 3D des matériaux cimentaires. De plus, au cours de cette phase, une analyse de décision d'achat a été menée afin d'évaluer les alternatives pour s’équiper d’une imprimante 3D pour béton à grande échelle à l'Université de Sherbrooke. Plusieurs options ont été envisagées, un robot portique cartésien à 4 axes a été conçu et conceptualisé pour fabrication. Dans la Phase 2, l'efficacité des méthodes rhéométriques pour évaluer la structuration structurelle des matériaux cimentaires destinés pour une impression 3D a été étudiée. À cette fin, des méthodes d'essais empiriques, tel que le mini-cône d'affaissement, ainsi que des méthodes rhéométriques ont été adaptées. Dans le cas des propriétés rhéologiques, les paramètres rhéologiques ont été estimés en utilisant le modèle de Bingham modifié identifiés pour une large gamme de de matériaux et utilisés pour l’étude d'optimisation. La structuration structurale des mélanges a donc été mesurée en utilisant l'évolution des seuils d’écoulement statique et dynamique. Les formulations de mortier ont été soumis à des essais d'impression 3D à l'aide d'une imprimante à l'échelle de laboratoire pour évaluer l'efficacité des méthodes de caractérisation empiriques et rhéométriques sur l'extrudabilité et la stabilité de forme des mélanges optimisés. Dans la Phase 3, des matériaux à base de ciment ayant un comportement thixotropique élevé ont été développés à l'aide d'adjuvants et additions minérales. Plusieurs mélanges ont ensuite été optimisés sur la base d'un critère de taux de structuration. Une étude de faisabilité a été menée à ce stade pour adapter un dispositif d'essai de compression pour les matériaux cimentaires à l’état frais. A cet effet, un prototype permettant un contrôle adéquat de la pression appliqué et un suivi très précis de de la déformation a été fabriqué. À l'étape suivante et après le réglage du prototype, une machine de compression uniaxiale a été fabriquée avec des caractéristiques uniques, notamment le protocole d'application de force de compression automatisé, le suivi de la déformation à une bonne résolution de 1 micron, la mobilité (le système nécessite uniquement une unité d'air comprimé) et l’interface d’usage conviviale. De plus, l'essai de compression uniaxiale a été utilisé pour développer une méthode d'essai afin de quantifier les propriétés des formulations destinées pour une impression 3D à l’état frais. Ceci est réalisé afin de surmonter les défis existants des méthodes d'essai rhéométrique lors de la mesure des propriétés rhéologiques de mélanges ayant une rigidité excessive. Initialement, certaines méthodes rhéométriques existantes pour obtenir le seuil d’écoulement statique des matériaux ont été utilisées pour caractériser les mortiers sélectionnés. Deuxièmement, l’essai de compression uniaxiale développé a été utilisée pour proposer un nouveau type de limite d'élasticité, à savoir la limite d'élasticité en compression. Enfin, dans le Phase 4, l'imprimante 3D à grande échelle de l'Université de Sherbrooke, fabriquée en parallèle des activités de recherche, a été utilisée pour effectuer des impressions 3D à grande échelle et valider la performance des méthodes d'essais afin de caractériser les formulations optimisées en termes d'extrudabilité et de constructibilité. De plus, l'effet du pompage et de l'extrusion sur l’histoire de cisaillement des matériaux a été étudié afin de pouvoir ainsi l’adapter au processus d'impression 3D. Les performances de la machine d'essai de compression ont été validées par l'obtention de la structuration structurelle des mortiers. De plus, une étude numérique a été réalisée pour simuler les variations de forme des matériaux cimentaires induites par le processus d'impression 3D

Ground Improvement by Deep Vibratory Methods

Vibro compaction and vibro stone columns are the two dynamic methods of soil improvement most commonly used worldwide. These methods have been developed over almost eighty years and are now of unrivalled importance as modern foundation measures. Vibro compaction works on granular soils by densification, and vibro stone columns are used to displace and reinforce fine-grained and cohesive soils by introducing inert material. This second edition includes also a chapter on vibro concrete columns constructed with almost identical depth vibrators. These small diameter concrete piles are increasingly used as ground improvement methods for moderately loaded large spread foundations, although the original soil characteristics are only marginally improved. This practical guide for professional geotechnical engineers and graduate students systematically covers the theoretical basis and design principles behind the methods, the equipment used during their execution, and state of the art procedures for quality assurance and data acquisition. All the chapters are updated in line with recent developments and improvements in the methods and equipment. Fresh case studies from around the world illustrate the wide range of possible applications. The book concludes with variations to methods, evaluates the economic and environmental benefits of the methods, and gives contractual guidance