Accurate estimation of the in situ strength of concrete at early age is very important as it provides the necessary information required to start subsequent construction operations. Overestimation of the strength may cause serious safety hazards and underestimation may lead to unnecessary costly delays. This study investigates the performance of the maturity method in estimating the strength of in

The seismic performance of shear walls reinforced with high‐strength bars has been experimentally studied in depth; however, limited analytical research exists on such walls. As part of this study, two shear walls reinforced with Grade HRB 600 bars and subjected to different axial load ratios (0.1 and 0.2) were tested under cyclic loading to study their hysteretic performance. As part of the analytical

The present study aims to characterize the epistemic uncertainty within the use of global non‐linear numerical analyses (i.e., NLNAs) for design and assessment purposes of slender reinforced concrete (RC) members. The epistemic uncertainty associated to NLNAs may be represented by approximations and choices performed during the definition of a structural numerical model. In order to quantify epistemic

Most existing studies on fiber reinforced polymer (FRP) confined concrete have focused on undamaged concrete that is subjected to uniaxial monotonic compression. However, FRP jackets are usually applied to concrete columns with existing material damage and potential future damage. This paper investigates FRP confinement on concrete with damage before and after FRP jacketing. A total of 32 FRP‐confined

In order to better understand the interfacial fatigue behavior of concrete and fiber‐reinforced polymer (FRP), bending fatigue tests were conducted on plain concrete beams strengthened with carbon FRP (CFRP) sheets under variable amplitude cyclic loading which deteriorates structural performance in actual projects more dramatically than constant amplitude loading. The test parameters were four types

After several decades of research studies, design rules for fiber reinforced concrete (FRC) are now available for several structural elements. Starting from standard tests, it is possible to determine design parameters and constitutive laws to perform simplified sectional verifications and/or numerical analyses. However, one of the main issues still open is represented by the fiber orientation in the

This paper presents a sectional analysis of cracked fiber reinforced concrete (FRC) under flexural loading. The approach considers three separate loading conditions: monotonic, cyclic, and creep bending loads. Different parts of the approach are experimentally calibrated and validated with tests on polypropylene FRC. In the monotonic regime, numerical optimization is used to find the optimal stress–strain

This article presents the effect of LaSrCoO3, oxides commonly known as LSCO nanomaterials, on rheological, mechanical and microstructural properties of self‐compacting concrete (SCC). LSCO nanomaterials contents of 1–4 wt% are considered in this study. Compressive, flexural and split tensile strengths of SCC mixes are evaluated at curing ages of 7, 28, and 90 days. The effect of LSCO nanomaterials

This issue of Structural Concrete is partially dedicated to the conceptual design of structures and gathers extended versions of some papers presented at the International fib Symposium on Conceptual Design of Structures held in Madrid, Spain, from 26th to 28th September 2019 and some additional related papers as well. The symposium, jointly organized by the fib and the Spanish Association of Structural

Large‐diameter shield‐driven tunnels are widely adopted in road projects to accommodate the increasing traffic load all over the world. As the diameter of lining ring increases, the jointed segmental lining will be subject to more complex external loading condition, which results in highly nonuniform and nonlinear internal forces. The segment joints, depending on loading condition, would exhibit different

A new method of assembling precast concrete (PC) wall panels is proposed to establish a stable and reliable earthquake‐resistant system. The dry‐connection method is recommended by welding energy‐absorbing connectors with mild steel plates at the vertical joints between adjacent walls. The connectors replace cast‐in‐place (CIP) constructions to rapidly and efficiently connect wall panels and utilize

Ultra‐high performance concrete‐normal strength concrete (UHPC‐NC) composite beam is a brand‐new composite structure. UHPC‐NC composite beam not only has the interfacial problem of the two materials, but its shear resistance should be investigated, which directly determines the mechanical performance and engineering value. In this article, the finite element analysis (FEA) method combined with the

Innovative drilling methods gain importance in the field of post‐installed fasteners. For this reason, users, customers and manufacturers demand methods other than the standard drilling procedure of hammer drilling, as they are hollow drilling with included cleaning and diamond drilling without emitting drill dust. One open question regarding these drilling methods is the equivalence of the behavior

In this study, the behavior of axially loaded plain and fiber‐reinforced geopolymer concrete columns reinforced with glass fiber‐reinforced polymer (GFRP) bars and helices was investigated. Ten ambient‐cured geopolymer concrete columns of 160 mm diameter and 640 mm height were cast and tested under concentric axial loads. The behavior of the columns was investigated under the effect of the type of

This paper studies the effectiveness of bonding carbon fiber reinforced polymer (CFRP) with additional wraps or anchors to strengthen reinforced concrete (RC) arches resisting blast loads, which is of great significance to optimize the CFRP strengthening methods. To improve the anti‐explosion behavior, RC arches are bonded with CFRP sheets in longitudinal and transverse directions, and anti‐explosion

This paper deals with numerical analysis on the mechanical behavior of ultrahigh performance concrete (UHPC) under uniaxial compression. For the modeling of the mechanical behavior of UHPC, the mesh‐free discrete element method was applied. To calibrate the model parameters and validate the numerical simulation results, a set of experimental investigations including mechanical tests, microscopy and

Prestressed Concrete Cylinder Pipes (PCCP) form the backbone of water and wastewater infrastructure networks in North America. Failure of buried PCCP is a common occurrence due to structural deterioration or manufacturing defects. To mitigate the serious effects of such failures, owners and operators of these networks use risk curves to predict the failure of PCCP when given a certain level of deterioration

Most of the RC buildings in Turkey have reached the end of their economic lifespan, so urban transformation studies have been accelerated in recent years. Considering the fact that these buildings do not meet the construction regulations and have structural defects in terms of earthquake resistance is concluded the necessity of renewal of this building stock. For this reason, it is needed to study

Prestressed concrete cylinder pipe (PCCP) is widely used in hydraulic engineering. The bell‐and‐spigot joint is a weak point along a PCCP pipeline, since damage of joint can affect the operation of the whole pipeline. In this paper, a three‐dimensional numerical model of buried PCCP, considering the simulation of rubber gasket in bell‐and‐spigot joint is established. The fluid–structure coupling of

Utilizing steel slag and recycled concrete as fine aggregate could save the consumption of natural resource and reduce the environmental pollution. In this work, the effect of steel slag aggregate and recycled aggregate on the compressive strength and chloride migration coefficient of three types of concretes were investigated and compared with natural aggregate. The interfacial transition zone (ITZ)

This study investigates the feasibility of completely replacing traditional mesh reinforcement with non‐corrodible fiber‐reinforced mortar (FRM) in secondary roofing slabs. Patch‐load tests were conducted on 36 secondary roofing slabs containing mesh reinforcement, FRM with polyester or structural synthetic fibers only, or a combination of these. The ferrocement specimens carried the highest load but

The use of recycled aggregate (RA) to produce recycled aggregate concrete (RAC) is a proven way of decreasing the consumption of natural aggregate (NA) and the landfilling of construction and demolition waste. However, adoption of codes for the design of RAC and RAC structures has been lacking. Within the framework of the new fib Model Code 2020 and Eurocode 2, provisions for RAC can be adopted. Therefore

An experimental and analytical study on 15 specimens of lap splices embedded in nonconventional concrete without confining reinforcement was performed under direct tension. The experimental program involved two groups of straight‐ended and anchored‐ended bars; three different techniques were employed with different splice lengths. For straight‐ended bars, conventional lap splice was studied as a benchmark

Square‐rebar reinforced concrete structures during the republic of China (ROC) (1912–1949) have special material properties and structural characteristics. To perform nonlinear finite element simulations of this special type of structure more accurately, a specialized bond‐slip constitutive model is built. Eighteen central pullout specimens were designed based on the ROC concrete mix proportions and

Due to the outstanding mechanical properties of the reactive powder concrete (RPC), it has attracted a great deal of attention. In which, incorporating fibers can improve its behavior and properties. The main objectives of this study were to consider different mixing methods and the effect of fiber content and type on the mechanical properties of RPC. The best mix proportion was selected for the final

Experimental research has shown the extraordinary potential of the addition of short fibers to cement‐based materials by improving significantly the behavior of concrete structures for serviceability and ultimate limit states. Software based on the finite element method has been used for the simulation of the material nonlinear behavior of fiber‐reinforced concrete (FRC) structures. The applicability

Electrically conductive cementitious composite (ECCC) can be utilized in traffic detection, structural health monitoring (SHM), and pavement deicing. Graphite is a popular conductive filler given its outstanding electrical resistance behavior, but its flat micro‐surface decreases the friction resistance, reducing mechanical strength. However, slag solids can substitute part of the graphite with their

Cut off walls are used under dams for the control of sub surfaces seepage and permeability of cut off wall was important. In the construction of cut off walls, plastic concrete is used and the amount of plastic concrete permeability is important. In this study, the permeability of plastic concrete was investigated and the effect of replacing nano silica instead of cement to reduce permeability was

A series of tests were conducted to study the variability of the residual compressive strength for high‐strength concrete (HSC) after elevated temperatures, and then a calculation process was developed to study the reliability of the residual moment capacity of HSC beams after a fire. The experimental results indicated that the mean values and the characteristic values of the residual compressive strength

This paper describes a numerical study of the punching shear resistance of unbonded post‐tensioned slabs without shear reinforcement. This research aimed to develop a methodology for modeling unbonded tendons and numerically evaluate the prestressing effects on the punching shear capacity. To validate the modeling approach, a series of well documented experimental tests were simulated using the finite

1 INTRODUCTION The reliable determination of the end of service life of structures actually gets a lot of attention. Considerable effort is invested in improving models for chloride penetration, carbonation, frost‐thaw attack, and alkali aggregate reaction. However, at least as important is the question how to prolong the service life of existing structures which are subject of deterioration and have

Screwed‐head fastener is the common fabricated hold‐down bolt for steel structures and machine foundations. Although different models are available for evaluating its structural behavior, there are still aspects that need to be investigated. In particular, conflicting approaches for the design can be found among the European design‐oriented documents. Within this context, a comprehensive experimental

Advanced experimental evaluation of the mechanical fracture properties of quasi‐brittle materials is an important part of the design, assessment, and computational modeling of structures made of these materials. The aim is to determine parameters independent of the test configuration or the size of the test specimens. This paper presents the results of an extensive experimental program which is part

The construction of new kerbs or the replacement of existing ones is usually due to the need of installing safety or anti‐noise barriers. A suitable experimental survey has been studied and developed at the Laboratory of the University of Rome “Tor Vergata" aiming at verifying the vulnerability of the system kerb safety barrier in a bridge deck. The main scope is the analysis, through full‐scale experimental

Shrinkage of concrete refers to the volumetric change of concrete due to cement hydration (i.e., self‐desiccation) and environmental drying (i.e., water evaporation). It creates dimensional instability and induces tensile stress when the concrete is restrained that may be large enough to cause cracking. The most fundamental way to mitigate concrete shrinkage is to decrease the shrinkage of cementitious

Chloride‐induced corrosion of reinforced concrete (RC) is one of the main reasons for decreasing the seismic performance level of RC structures over their lifetime. In the present study, base shear capacity and ductility were considered as criteria for evaluating seismic performance of the RC frame. The impact of corrosion on the ductility and base shear capacity of a two‐dimensional single‐story single‐span

Extensive damage to the bridges in recent earthquakes has revealed the vulnerability of these structures to the seismic excitation. Bridge piers play a key role in maintaining the operability of the bridge structure during and after earthquakes. As determinant elements in single‐pier bridges, wall piers significantly affect the bridge structure behavior. Hence, the present experimental study was conducted

This paper investigates the effects of coral sand powder (CSP) and corrosion inhibitors (SBT®‐ZX(V), SBT®‐RMA(II)) on reinforcement corrosion in coral aggregate seawater concrete (CASC) in a marine environment. A reasonable time‐variation model for reinforcement corrosion in CASC is proposed and verified. Based on the time‐variation model and chloride diffusion model, the cracking time and service

In order to reduce the crushing damage at shear wall corners and improve the seismic behavior of ordinary concrete shear walls, this paper develops a high‐performance steel‐polyvinyl alcohol (S‐PVA) hybrid fiber‐reinforced concrete (HyFRC) shear wall. Two‐phase studies from experiment to numerical analysis were carried out. The first phase investigates the seismic behavior of S‐PVA HyFRC shear walls

This paper presents an experimental and analytical study on the age‐dependent mechanical properties of geopolymer concrete. The effect of total aggregate content and the ratio of sand‐to‐total aggregate content on the engineering properties of geopolymer concrete has been investigated. Geopolymer concrete cubes, prisms, and cylinders were prepared and tested for evaluation of the engineering properties

Models are proposed for the shear strength of joints, for seismic design or assessment. At first Level‐of‐Approximation, the joint reinforcement and the column axial force are lumped in a single central Tie in the corresponding direction, whose ends are connected through concrete Struts to the two compressed corners of the joint. Concrete strength and Strut widths are independent of strains. At the

Despite the key role of thin‐walled tubular reinforced concrete (RC) members in major critical infrastructure projects, for example, bridges, their torsional performance is still not well understood and the effectiveness of strengthening systems cannot be easily assessed, especially when using innovative strengthening materials. With a large part of critical infrastructure approaching its design service

In many industrialized countries, structural assessment of existing structures and infrastructure is becoming a crucial issue. Since many of them have already reached their design service life, assessing their actual condition in order to evaluate their remaining service life is, today, of fundamental importance. Depending on the environmental conditions, carbonation‐induced corrosion, chloride‐induced

In the present MC 2010 the propagation period, addressing degradation processes, was not included said due to the lack of data to allow for a sound validation. However, taking account of the propagation period is essential for the assessment of existing reinforced concrete structures. In addition, considering the propagation period is relevant for the probabilistic definition of the service life, as

This paper is to study the influence of sulphate corrosion on the mechanical behaviors of concrete, especially concrete corrosion under actual corrosion environment. This study investigated different immersion methods for concrete in a corrosion environment, and different strengths of concrete specimens with contents of sodium sulphate and magnesium chloride of 10.36% and 12.00%, respectively. Strength

The steel corrosion in magnesium oxychloride cement (MOC) restrains the application and popularization of MOC products. However, MOC is a green cementitious material. Therefore, it is necessary to solve the steel corrosion in MOC. Aiming at this issue, firstly, the Stern–Geary constant (B) applied to the steel corrosion in MOC was calculated and verified. Secondly, the influence of different steel

This paper critically evaluates the cracking model of MC 2010 with a view to the drafting of MC 2020. It emphasizes that there are differences in cracking behavior in tension and bending, which are not adequately recognized in the current model. Based on the analysis of experimental evidence, it shows that the current model has a significant skew in prediction performance when tension and flexure tests

In this large‐scale field study we use a prototype impact‐echo scanner to detect delaminations on a concrete bridge deck surveying in total over 17,000 m2. Delaminated bridge sections are known from manual sounding and coring. A large‐scale damage assessment is necessary to identify the need of repair work. Based on first results, two lanes of the bridge are repaired and in subsequent tests the bonding

The present work analyses the basic creep of concrete compositions for which 75% of Portland cement is substituted by limestone filler and/or blast furnace slag. Compressive creep tests are performed during and after the peak of hydration of the slag in order to track the effect of the slag on the development of the creep properties. An adapted version of the Model Code 2010 (MC2010) is used to model

In this study, steel reinforced grout (SRG) is proposed for shear strengthening of reinforced concrete (RC) beams using the near‐surface embedded (NSE) technique. It is believed based on several research contributions in the literature that the NSE technique precludes or delays the onset of premature debonding and achieves higher strength increase in strengthened beams compared to the externally bonded

The use of waste glass in concrete can bring significant economic and environmental benefits due to reduction of landfills and demand for natural aggregates. This paper presents a comprehensive investigation on the feasibility of using high volume of waste glass as fine aggregate in self‐compacting concrete (SCC). A detailed investigation on fresh behavior of mixtures was performed by evaluating filling

Self‐sensing composites are now becoming extremely attractive for the applications in civil engineering structures in order to enhance the safety and service life. In the new generation carbon nanofibers (CNFs) and nanotubes (CNTs) have shown good electrical, mechanical, and thermal parameters which inspired in the development of innovative nanocomposites with great and multifunctional properties.

Due to the visco‐elasto‐plastic material behavior, the added energy to concrete specimens during fatigue tests is transformed into another form of energy. Besides the description of the energetic material behavior of concrete, the elastic and the plastic part of the energy as well as the dissipation energy are analyzed for different specimens. Especially the dissipation energy shows a correlation with

Present work demonstrates the experimental investigation on four large scale reinforced concrete (RC) beams cast with and without smart concrete to study strain and damage sensing properties (for health monitoring), effect of carbon fiber (CF) on ultimate strength, crack pattern, and stiffness response under monotonically increased loading. A total of four beams, one without and three with smart concrete

The main objective of this research is to explore the seismic performance of the group silos through the shaking table tests and the finite element analysis. The 1/16 scaled model of reinforced concrete silos supported by supporting wall was designed and constructed. The shaking table tests were carried out with gradually increasing table‐input acceleration amplitudes. The dynamic characteristics,

The steam curing technology is worldwide applied in the production of concrete prefabricated components, including the production of track slab and girder used for the high‐speed railway in China. However, the steam curing process at elevated temperature will often generate the heat damage on concrete and thus degrade the long‐term performance of the steam‐cured concrete prefabricated components. It

In the construction of major tunnel structures, large quantities of rock material are generated by the excavation of, for example, tunnels or caverns out of the in situ rock mass. Excavated rock material was often considered as undesired by‐product and from a legal point of view as waste in the past. Nevertheless, there is the need for construction material at the tunnel construction site directly

In this study, a total of six full‐scale sandwich columns were fabricated, and experiments on their load transfer performance were conducted. The effects of steel fiber reinforcement and the ratio of the column width to the slab thickness on the effective compressive strength were theoretically analyzed, and briefly compared the test results of full‐ and reduced‐scale specimens. The current design

Precast concrete structures have satisfactory performances in quality control and construction progress. This article experimentally studied the seismic behavior of a type of precast beam‐column connection. Three full‐scale specimens are designed with different longitudinal reinforcement ratios and details of connections. Precast beam‐column connections are systematically investigated focusing on their

Fiber Reinforced Shotcrete (FRS) is an essential element of ground control in many types of underground structure. It has been found to be an important aid to the improvement of safety in underground spaces and is a highly effective method of ground control across a wide range of ground conditions. However, the design of FRS linings remains problematic and uncertainty exists regarding the true load