Shear and fracture behavior of high performance concretes

Concrete is the most widely used man-made material in the world. Like other materials, it has been improved over time. Nowadays, with continued development of science and technology, a new generation of concretes is produced and is termed high performance concretes. A review of previously published work indicates that very few studies (in some cases none) have addressed the structural behavior of full-scale, high performance concrete elements. This study investigated the shear and fracture behavior of two types of high performance concrete - high-volume fly ash concrete (HVFAC) and self-consolidating concrete (SCC). The HVFAC incorporates up to 70% cement replacement with fly ash, and the SCC is based on using only chemical admixtures to convert a conventional concrete (CC) mix to a SCC mix with all of the necessary passing, filling, flowability, and stability requirements typically found in SCC. This experimental program consisted of 16 shear beams (12 without shear reinforcing and four with shear reinforcing in the form of stirrups) and also 16 fracture mechanics beams for each type of concrete investigated (HVFAC and SCC). Additionally, three different longitudinal reinforcement ratios were evaluated within the test matrix of shear beams. The shear beams were tested under a simply supported four-point loading condition. Results of this study showed that the HVFAC had higher shear strength and fracture energy compared with the CC, while the SCC showed higher fracture energy, but the same shear strength as the CC --Abstract, page i

THE REFLECTION OF WATER RESOURCE MANAGEMENT POLICIES IN THE NEWS: A CRITICAL DISCOURSE ANALYSIS

Abstract. This study was mainly concerned with corpus analysis of the news gathered from Tehran Times, an international English newspaper of Iran, in 2017 regarding the officials commenting in water resource management issues in Iran. A corpus of 15 (above 3000 words) news pieces selected according to the content and topic was analyzed. The news were classified under officials' concern, their criticism the past and current plans and calling for attention, and their hopelessness. All in all, the news show a dark hopeless future of water resource in Iran.Keyword: News value, water resource, ideology, discourse analysis

THE REFLECTION OF WATER RESOURCE MANAGEMENT POLICIES IN THE NEWS: A CRITICAL DISCOURSE ANALYSIS

Abstract. This study was mainly concerned with corpus analysis of the news gathered from Tehran Times, an international English newspaper of Iran, in 2017 regarding the officials commenting in water resource management issues in Iran. A corpus of 15 (above 3000 words) news pieces selected according to the content and topic was analyzed. The news were classified under officials' concern, their criticism the past and current plans and calling for attention, and their hopelessness. All in all, the news show a dark hopeless future of water resource in Iran.Keyword: News value, water resource, ideology, discourse analysis

Hybrid Jacketing for Rapid Repair of Seismically Damaged Reinforced Concrete Columns

This study proposes hybrid jacketing for rapid repair of seismically damaged concrete columns for bridge safety. The hybrid jacketing for a reinforced concrete (RC) column is composed of a thin cold-formed steel sheet wrapped around the column and its outside prestressing strands. Although the prestressing strands can prevent buckling of the confining steel sheet, the steel sheet can in turn prevent the prestressing strands from cutting into the concrete. The hybrid jacketing concept was validated with testing of a large-scale RC column with lap splice deficiency typical of pre-1970 bridge constructions in the Central United States. Results from the original and repaired columns were compared for hysteresis loops, strength, stiffness, ductility, and energy dissipation. The hybrid jacketing proved to be effective in restoring structural behavior of the damaged column to prevent bridge collapse. Such a cost-effective solution can be implemented at bridge sites in hours. Design equations to establish the lateral force-displacement relationship of the tested column to design the hybrid jacket are derived in detail

An Investigation of Epistemological Markers in Socio-political Forums on Iranian TV Channels from a Critical Discourse Analysis Perspective

The present article examines epistemological markers in socio-political forums on Iranian TV channels from the critical discourse analysis point of view based on Hyland (2005) and Fairclough (2001).  In this study, 20 selected socio-political panels of 1,2, 3 & 4 channels have been selected, which are samples have been analyzed in qualitatively and quantitatively way in the form of all of them using targeted sampling. The variables studied in this study to be determined by this factors, the gender of the experts, using the live or recorded programs, the number of experts in each program, whether the experts are academic or non-academic. The distribution of epistemological elements in live and recorded programs and the presence of male and female critics and the presence of academic and non-academic factors is different?  Also the distribution of elements in the recorded political and social panels is different with the presence of one or more critics? How the differences between the distributions of elements justified are based on Fairclough discourse analysis model? The results showed that the distribution of hedges, boosters, Attitude markers in the programs of socio-political panels in the Islamic Republic of Iran Broadcasting based on the gender of experts, alive or recorded programs, academic or non-academic experts or the presence of one or more experts in each programs are different. Also, based on discourse analysis patterns, can be justified type of using of epistemological tools in the discourse of experts

Analysis of Transportation Networks Subject To Natural Hazards – insights from a Colombian case

ABSTRACT: This study provides an applied framework to derive the connectivity reliability and vulnerability of inter-urban transportation systems under network disruptions. The proposed model integrates statistical reliability analysis to find the reliability and vulnerability of transportation networks. Most of the modern research in this field has focused on urban transportation networks where the primary concerns are guaranteeing predefined standards of capacity and travel time. However, at a regional and national level, especially in developing countries, the connectivity of remote populations in the case of disaster is of utmost importance. The applicability of the framework is demonstrated with a case study in the state of Antioquia, Colombia, using historical records from the 2010-2011 rainy season, an aspect that stands out and gives additional support compared to previous studies that considers simulated data from assumed distributions. The results provide significant insights to practitioners and researchers for the design and management of transportation systems and route planning strategies under this type of disruptions

Effect of Recycled Concrete Aggregate Replacement Level on Shear Strength of Reinforced Concrete Beams

An experimental investigation was conducted to study the mechanical properties and shear strength of full-scale beams constructed with recycled concrete aggregate (RCA). This study included two RCA mixtures and one conventional concrete (CC) mixture. The two RCA mixtures are different in the amount of RCA replacement, with one mixture replacing 50% of the virgin aggregate with RCA (RAC50) and the other replacing 100% (RAC100). This experimental program consisted of 18 beams with three different longitudinal reinforcement ratios. The experimental shear strengths of the beams were compared with the shear provisions of both U.S. and international design codes. Furthermore, the shear strengths of the beams were evaluated based on fracture mechanics approaches, Modified Compression Field Theory (MCFT), and a shear database of CC specimens. In addition, statistical data analyses were performed to evaluate whether there is any statistically significant difference between the shear strength of the recycled-aggregate concrete (RAC) and CC beams. Results of this study show that the RAC100 has 11% lower shear strength, on average, compared with the RAC50 and CC beams; however, the RAC50 and CC beams showed similar shear resistance. The decrease in basic mechanical properties (splitting tensile strength, flexural strength, and fracture energy) for the RAC parallels the decrease in full-scale shear behavior and can be used as a predictor in mixtures containing recycled concrete as aggregate