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

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