The experimental results of the bond behavior between glass fiber reinforced polymer (GFRP) bars and concrete under several aggressive environments were studied. To give a comprehensive and comparative evaluation, a total 60 GFRP bar-concrete pullout specimens were divided into a control group and a treated group being immersed in tap water, alkaline and saline solutions for up to 270 days. The influences

Considering the low-permeability of reactive powder concrete (RPC) and the influence of pressurized liquid on crack development, this paper studies the mechanical properties of sealed and unsealed prismatic RPC samples under different confining pressures. It is determined that the stress-strain relations of sealed and unsealed RPC samples are almost consistent before the stress reaches its proportional

Inspection data of actual concrete structures should be analyzed to elucidate the deterioration mechanism and construct a regression model. Although machine learning can be applied to this problem, inspection data are not suitable because machine learning targets big data with a uniform density and a balanced distribution. This study applies machine learning to a regression model of the crack damage

Shear failure experiments of concrete beams containing a weak layer were conducted with a focus on the bifurcation of shear localization appearing at the boundary between structure and soil foundation. Low-strength concrete, which is analogous to artificial soft rocks and strengthened foundation, was used to create a weak layer that caused dispersal and bifurcation of the shear localization area, resulting

Fiber Reinforced Polymer (FRP) composites in the form of laminates and fabrics are installed on reinforced concrete members, using externally bonded (EB) techniques for strengthening. However, the utilisation of capacity of FRP composites is limited due to debonding observed in the strengthening system, due to FRP and concrete interfacial shear stress. Carbon fiber reinforced polymer (CFRP), in a new

Recent progress in finite element analysis aids the simulation of seismic vibration of an entire reinforced concrete (RC) building structure and indicates that drying shrinkage cracks affect seismic resistance performance. Polypropylene fiber-reinforced concrete (PFRC) is a promising material since the fibers will reduce the cracks and strains under drying shrinkage. This paper attempts to quantify

The corrosion morphology and the mechanical behavior of corroded prestressing strands are investigated in the present study. Nineteen corroded strands are obtained through controlling stress level, corrosion time and chloride ion concentration under artificial climate conditions. A total of 119 corrosion pits are counted to investigate the geometric morphology of corrosion pits. A depth-width ratio

Mechanical properties of calcium silicate hydrates (C-S-H) with C/S ratios of 0.75, 1, and 1.33 were examined with nanoindentation after gamma-adsorbed doses of 0.145, 0.280, 0.500, and 0.784 MGy, and were compared with control samples. Young' s modulus and stress relaxation tests showed no apparent trend with irradiation dose. Qualitatively, most of the irradiated samples were found to relax more

In this study, a method was developed to estimate accurately the chloride threshold value for corrosion initiation in reinforced concrete. In this method, chlorides are supplied through a part of the specimen surface, and half-cell potential between the rebar and reference electrode embedded in a concrete specimen was measured in every ten minutes. A sudden drop of half-cell potential was observed

During sorption, the microstructural evolutions of two different cement pastes (with water-to-cement ratios of 0.40 and 0.55) are studied via proton-nuclear-magnetic-resonance relaxometry. The water uptake test is performed for samples dried at 105°C under three different temperatures of 20°C, 40°C, and 60°C for the first twenty-six days of sorption. It is observed that the water went first to the

This paper introduces a novel and simple model for estimation of the shear contribution of the fiber-reinforced polymer (FRP) strengthening system in the FRP-strengthened beams. The model utilizes the bonding-based approach, which considers the shear resisting mechanism of FRP-strengthened beam via the bond behavior between FRP strengthening system and concrete. Herein, the beams strengthened in shear

In nuclear power plants, concretes used for biological shielding walls are exposed to radiation such as neutrons and gamma rays over the long-term operation of the plant. Previous studies have reported that neutron irradiation causes aggregate expansion due to the metamictization of quartz and feldspar leading to reduced density and a loss of the compressive strength and Young' s modulus of the concrete

In this study, the effects of Perlite, Leca, and Scoria as lightweight aggregates have been investigated on the properties of self-compacting concrete at the fresh and hardened phases. For this purpose, the ratio of water to cement and super lubricant were kept constant in the mixing rules. Performance tests, such as Slump flow, J ring, U box, L box, and V-funnel tests, were used to investigate the

To evaluate the radiation-induced degradation of concrete, a rigid-body spring network model is introduced that takes into account the three phases in concrete: mortar, aggregate, and the interfacial transition zone. The proposed model enables evaluation of the change in the physical properties of concrete affected by aggregate expansion under the free restraint condition. Good agreement with previous

Due to their wide applicability in inspection of concrete structures, there is considerable interest in the development of automated crack detection method by image processing. However, the accuracy of existing methods tends to be influenced by the existence of traces of tie-rod holes and formworks. In order to reduce these influences, this paper proposes a crack detection method based on semantic

Aiming at improving bond strengths between FRP sheet and concrete, the FRP sheet bonding method using high elongation elastic resin as a buffer layer was developed. In this study, bonding tests was conducted to clarify the basic bond characteristics of FRP strand sheet-concrete interface with a polyurea resin. As a result of the bonding tests, it was found that the use of the polyurea resin as a buffer

The adhesion failure of the interface between concrete and rendering mortars often leads to the degradation of the reinforced concrete building envelopes. Although several methods to improve the adhesion properties between concrete and rendering mortar have been proposed, there is no system to evaluate the effectiveness of these methods from the perspective of durability. To this end, this study proposed

In this research, concrete-filled braided carbon fibre-reinforced polymer (CFRP) tubular beams and arches were constructed. CFRP tubes and concrete-filled CFRP tubular cylinders were compressed to investigate the constraint effect of the CFRP tube on the concrete. Long and short beams were bent to reveal the deformation styles and the failure modes controlled the flexure and the shear, respectively

A mix-design method based on packing model was used to optimize the mix proportion of Reactive Powder Concrete (RPC) containing phosphorous slag in this paper. The design aimed to achieve a densely compacted matrix by applying the modified Andreasen particle packing model, i.e., the Dinger-Funk particle size distribution (PSD) equation. MATLAB and Excel Solver Tool were utilized to implement the calculation

The steel-plate bonding method used to reinforce concrete slabs in bridges has a long record of adoption, and has played an important role for many years. Favorable conditions have been observed with this method in periodic inspections; however, as part of durability tests, decreases in strength of the epoxy resin adhesive (which is one of its component materials) have been observed following over

In this study, thermoporometry by differential scanning calorimetry and proton NMR measurements of hardened cement paste equilibrated under different humidity conditions were carried out, and the results of both measurements were compared. The results reveal that thermoporometry by low temperature DSC measurement cannot detect the water present in samples equilibrated at low relative humidity. On the

The present research aimed at evaluating early age thermal cracking risk of durable RC slabs incorporating slag cement and expansive additive on multiple span steel box girder bridges utilizing full-scale 3D FEM simulation. First, laboratory investigations were conducted to calibrate the material models of durable concrete. Second, the material models were utilized in several member level FEM models

Explosive spalling is a severe threat to concrete at high temperature. The addition of steel fibers is believed to be useful to mitigate explosive spalling of concrete. But predicting explosive spalling of steel fiber reinforced concrete remains to be a challenging topic. This paper adopted a popular machine learning approach, i.e., artificial neural network (ANN), to predict explosive spalling of

The objective of this research is to propose a simple and accurate prediction method for the shear capacity of reinforced concrete beams with steel fiber (RSF beams). Steel fiber reinforced concrete (SFRC) is being widely used nowadays, with the steel fibers added to the concrete to improve the tensile resistance. First, this research aims to investigate the material properties of SFRC in various concrete

In view of the life-cycle assessment of concrete pavement, three-dimensional behavioral simulation was conducted by integrating constitutive laws for cracked/uncracked reinforced concrete, modeling of pore water inside cracks and multiyield surface plasticity for soil to investigate the fatigue life under high-cycle moving loads. Presented is a discussion that the balanced pavement requires thicker

Recent studies in the field of concrete materials show that the early cracking criteria in micro-size can occur as soon as the cement matrix becomes hardened. In many ways, these cracks can become macro-size and opened cracks resulting in significant issues for the durability and appearance of concrete structures as water leakage and corrosion. The technique of self-healing using bacteria has recently

Multiple factors, regarding mechanical properties, load levels, and environmental conditions, affect the fatigue lifetime of reinforced concrete (RC) bridge decks. For the mechanical behavior, previous research predicts the fatigue lifetime of RC decks as a function of their punching shear capacity, where they give less attention to other modes of failure due to experimental limitations of fatigue

The Fukushima-Daiichi nuclear power station accident in East Japan in 2011 released radioactive cesium (r-Cs) into the surrounding environment. In addition to the major contamination of soil and vegetation, surrounding concrete structures have also been contaminated. Understanding the contamination characteristics is important for the decontamination or disposal of offsite and onsite concrete structures

Plant concretes were developed and are currently used as filling material in a timber frame. Their properties are strongly related to the bio-aggregates characteristics. In addition, since hemp shiv, the reference bio-based aggregate, has a limited availability, it is necessary to consider alternative bio-aggregates largely and locally available. Thus, this paper focused on identifying and understanding

This paper describes the research and development of an inspection diagnostic system that applies robot technology to the detailed inspection of infrastructure such as concrete walls in high places. ALP uses a vacuum suction pad improved by testing on real structures as a moving mechanism. ALP is also fitted with a measurement system that consists of a high-resolution camera, an electromagnetic wave