This book is the result of a Special Issue published in Applied Sciences, entitled “New Trends in Recycled Aggregate Concrete". It identifies emerging research areas within the field of recycled ...aggregate concrete and contributes to the increased use of this eco-efficient material.Its contents are organised in the following sections: Upscaling the use of recycled aggregate concrete in structural design; Large scale applications of recycled aggregate concrete; Long-term behaviour of recycled aggregate concrete; Performance of recycled aggregate concrete in very aggressive environments; Reliability of recycled aggregate concrete structures; Life cycle assessment of recycled aggregate concrete; New applications of recycled aggregate concrete.
•A model for assessment of anchorage of corroded reinforcement is proposed.•The model is shown to represent the physical behaviour well.•The full local bond stress-slip curve is obtained from the ...model.•Reasonably good agreement with a large database of bond test results is shown.
Corrosion of the reinforcement in concrete structures affects their structural capacity. This problem affects many existing concrete bridges and climate change is expected to worsen the situation in future. At the same time, assessment engineers lack simple and reliable calculation methods for assessing the structural capacity of structures damaged by corrosion. This paper further develops an existing model for assessing the anchorage capacity of corroded reinforcement. The new version is based on the local bond stress-slip relationships from fib Model Code 2010 and has been modified to account for corrosion. The model is verified against a database containing the results from nearly 500 bond tests and by comparison with an empirical model from the literature. The results show that the inherent scatter among bond tests is large, even within groups of similar confinement and corrosion level. Nevertheless, the assessment model that has been developed can represent the degradation of anchorage capacity due to corrosion reasonably well. This new development of the model is shown to represent the experimental data better than the previous version; it yields similar results to an empirical model in the literature. In contrast to many empirical models, the model developed here represents physical behaviour and shows the full local bond stress-slip relationship. Using this assessment model will increase the ability of professional engineers to estimate the anchorage capacity of corroded concrete structures.
A persistent rise in the costs of construction materials has led to the need to address this problem in line with the Sustainable Development Goals. This research employed vegetal soft and rigid ...fibers in a screed mortar to produce a sustainable fabric-cement matrix. Four different vegetal-dried fibers (hemp, flax, miscanthus, and bamboo) with dosages of 0.4, 0.6, 0.8, 1.2, 2, and 4 kg/msup.3 were used. Laboratory investigations were slump test, bulk density, air occluded, shrinkage, and mechanical strength. Scanning Electron Microscope (SEM) assessments were performed and analyzed on the natural fibers and the screed formulation. The results highlight that fiber dosages significantly influence the above-mentioned properties.
This reprint 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 this topic, from building materials to building structures. The current trend in the development of materials testing in civil engineering is mainly concerned with the detection of flaws and defects in elements and structures using destructive, semidestructive, and nondestructive testing.
This reprint 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 this topic, from building materials to building structures. The current trend in the development of materials testing in civil engineering is mainly concerned with the detection of flaws and defects in elements and structures using destructive, semidestructive, and nondestructive testing.
•A stress-path dependent axial stress-strain model of FRP-confined concrete is proposed.•The model considers stress-path history of confinement by using an adjusted active confined concrete ...stress.•The model was verified by 321 test results obtained by other researchers.
High-strength concrete (HSC) has higher strength-to-weight ratio and stiffness than normal-strength concrete (NSC). Therefore, the use of HSC can decrease the construction and demolition waste and embodied carbon content of structural members that enhances the urban sustainability. However, HSC is more brittle than NSC. To further push up the maximum concrete strength limit in practical construction, confining concrete by fibre-reinforced polymer (FRP) has been advocated to restore ductility. Compared with using hollow-steel tube as confinement, FRP has lighter weight, higher tensile strength, better corrosion resistance, and is more durable and flexible. Nevertheless, it is up to now a difficult task to predict accurately the uni-axial stress-strain behaviour of FRP-confined concrete since the effect of confining stress, concrete strength, hoop and axial strains are inter-related and need to be determined simultaneously. Herein, to better understand and simulate the behaviour of FRP-confined concrete, a stress-strain model has been developed, which consists of the following three main components: (1) A hoop strain equation elaborated from the authors’ previous study on steel-confined concrete columns for application to FRP-confined concrete; (2) A modified confined concrete model considering stress-path of confining stress (or history of hoop strain); (3) Interaction between FRP and concrete. The model was verified based on 321 test results obtained from the literature, the design application of the which to a broad range of FRP-confined concrete structures is thus ensured.
•Critical review of literature since 1980s on tensile performance of cast-in anchors.•Thorough investigation of concrete cone failure mode of cast-in anchors.•Recent developments and modifications to ...concrete cone design (CCD) method.•Shortcomings of current methods to assess concrete cone failure of cast-in anchors.
The Concrete Capacity Design (CCD) method, which was first proposed in 1995, has since been adopted in design standards worldwide because of its accuracy and simplicity. With advancements in concrete technology and construction industry, there are new applications whereby the behaviour of anchors cannot be predicted by the original formulation of the CCD method. This paper intends to provide a comprehensive review of the recent research on tensile behaviour of single cast-in headed anchors failing due to a concrete cone failure mode without the influence of concrete edge. The review includes, but is not limited to, studies on the effect of deep embedment of anchors, anchor head size, variation in size and shape of concrete aggregates, prestressed concrete, fibre-reinforced concrete, high strength concrete, lightweight concrete, as well as age of concrete at the time of loading on behaviour of anchors. Where discrepancy is found in the literature, critical review is presented through an in-depth examination of available results. In addition to recent modified (CCD) prediction models, older models are also presented for a better demonstration of how prediction models have evolved over the past five decades. The paper concludes with a detailed list of identified knowledge gaps in the area and proposals for future work.
Concrete is one of the most widely used construction material in the word today. The research in concrete follows the environment impact, economy, population and advanced technology. This special ...issue presents the recent numerical study for research in concrete. The research topic includes the finite element analysis, digital concrete, reinforcement technique without rebars and 3D printing.
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