Bora Gencturk

Bio: Bora Gencturk is an academic researcher from University of Southern California. The author has contributed to research in topics: Materials science & Rebar. The author has an hindex of 19, co-authored 94 publications receiving 1149 citations. Previous affiliations of Bora Gencturk include University of Houston & University of Illinois at Urbana–Champaign.

Carbonation-Induced and Chloride-Induced Corrosion in Reinforced Concrete Structures

Abstract: Corrosion is one of the most critical problems that impair the durability of RC structures. Both carbonation-induced and chloride-induced corrosion widely prevail in civil infrastructure around the globe. Expansive products are formed due to corrosion at the interface between concrete and reinforcing bar (rebar). The cracking and spalling in concrete due to expanding corrosion products and the reduction in the cross-sectional area of rebar jeopardize the safety and serviceability of RC structures. From an outsider perspective, this literature review summarizes the state of the art on the mechanisms of the two types of corrosion, mechanical degradation in RC structures as a result of these mechanisms, the analytical methods to predict the basic parameters most related to corrosion, and the available laboratory and field corrosion measurement techniques.

Effect of Elevated Temperature on Mechanical Properties of Limestone, Quartzite and Granite Concrete

Abstract: Although concrete is a noncombustible material, high temperatures such as those experienced during a fire have a negative effect on the mechanical properties. This paper studies the effect of elevated temperatures on the mechanical properties of limestone, quartzite and granite concrete. Samples from three different concrete mixes with limestone, quartzite and granite coarse aggregates were prepared. The test samples were subjected to temperatures ranging from 25 to 650 °C for a duration of 2 h. Mechanical properties of concrete including the compressive and tensile strength, modulus of elasticity, and ultimate strain in compression were obtained. Effects of temperature on resistance to degradation, thermal expansion and phase compositions of the aggregates were investigated. The results indicated that the mechanical properties of concrete are largely affected from elevated temperatures and the type of coarse aggregate used. The compressive and split tensile strength, and modulus of elasticity decreased with increasing temperature, while the ultimate strain in compression increased. Concrete made of granite coarse aggregate showed higher mechanical properties at all temperatures, followed by quartzite and limestone concretes. In addition to decomposition of cement paste, the imparity in thermal expansion behavior between cement paste and aggregates, and degradation and phase decomposition (and/or transition) of aggregates under high temperature were considered as main factors impacting the mechanical properties of concrete. The novelty of this research stems from the fact that three different aggregate types are comparatively evaluated, mechanisms are systemically analyzed, and empirical relationships are established to predict the residual compressive and tensile strength, elastic modulus, and ultimate compressive strain for concretes subjected to high temperatures.

Durability characteristics of high and ultra-high performance concretes

Abstract: Durability characteristics of high-performance concrete (HPC) and ultra-high performance concrete (UHPC) are evaluated in comparison to normal strength concrete (NSC). HPC and UHPC are cast using commonly available materials with no special heat treatment. Concrete resistivity, rapid chloride permeability, sorptivity, porosity, and resistance to chloride migration and carbonation of these three types of concrete are assessed. Microstructure and hydration products are investigated using scanning electron microscope (SEM) imaging and X-ray diffraction (XRD) analyses, respectively. Potential enhancement in the service life of reinforced concrete (RC) structures when concrete is replaced with HPC and UHPC is predicted using the time-to-corrosion model. Dense microstructures, high electrical resistance, negligible chloride permeability, low sorptivity, no carbonation ingress are observed in HPC and UHPC. The chloride diffusion coefficient was found to be at least three orders of magnitude lower in UHPC compared to NSC, which could delay the corrosion initiation of steel reinforcement. With such positive attributes, these concretes are expected to find more widespread application in concrete structures in harsh-climatic conditions. This paper provides additional data and analysis that could accelerate the adoption of these materials in practice.

Fundamentals of earthquake engineering

Abstract: PART 1 DEALS WITH THE DYNAMIC ASPECTS OF THE SUBJECT: MATHEMATICAL ANALYSIS OF SYSTEMS SUBJECTED TO INDEPENDENT VIBRATIONS BY MEANS OF MATHEMATICAL MODELS. THE ANALYTICAL SYSTEMS USED ARE NON-LINEAR SYSTEMS, HYDRODYNAMICS AND NUMERICAL METHODS. PART 2 EXAMINES SEISMIC MOVEMENTS, THE DYNAMIC BEHAVIOUR OF STRUCTURES AND THE BASIC CONCEPTS OF THE SEISMIC DESIGN OF STRUCTURES.

Corrosion of steel by concrete

Abstract: The author details the reactions of various concretes on steel reinforcement. Although portland cements, slag cements and high alumina cements are all hydraulic binders, each possess special properties which are examined. The discussion of causes and methods of preventing the corrosion of steel reinforcement covers such aspects as galvanised steel reinforcement, effects of concrete composition, corrosion of steel reinforcments in concrete and prestressed reinforcement. It is concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride; the presence of nitrates; the composition of the concrete; the degree of carbonation of the concrete; concrete compaction and, chlorides and sulphates should be used as far as possible when steel is embedded. (TRRL)

Design Of Concrete Structures

Abstract: Thank you very much for reading design of concrete structures. Maybe you have knowledge that, people have search hundreds times for their favorite novels like this design of concrete structures, but end up in harmful downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they cope with some infectious bugs inside their desktop computer. design of concrete structures is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the design of concrete structures is universally compatible with any devices to read.