Experimental investigation on mechanical properties of PCC and FRC confined with UPVC pipe

342-348This paper presents experimental investigation on improvement of mechanical properties of both plain cement concrete (PCC) and fibre reinforced concrete (FRC) confined with un-plastisized poly-vinyl chloride (UPVC) pipes, which has been considered for enhancing durability of concrete structures. UPVC pipes with outer diameter 160 mm and length 300 mm have been used with three different average thicknesses viz. 2.55 mm, 4.0 mm and 5.8 mm, respectively to explore its composite performance, effectiveness in strength and ductility improvement in construction industry particularly in corrosion environment. Three series of concrete M20, M25, M30 have been designed as per the latest version of Indian Standard Code of practice IS 10262:2009. A total of 54 concrete filled UPVC pipe specimen and 27 unconfined concrete control specimen have been cast and tested using displacement controlled universal testing machine having 2000 kN capacity. The modes of deformation, load-deformation curve have been noted and detail analysis & comparison has been made with unconfined, control specimen. Attempt has also been made to study UPVC pipe confinement effect on improvement of concrete strength and the load–deformation behaviour considering both PCC and FRC

Equity market anomalies in major European economies

This paper investigates five leading equity market anomalies – size, value, momentum, profitability, and asset growth, for four Western European markets, namely, Germany, France, Italy and Spain, from January 2002 to March 2018. The study tests whether these anomalies reverse under different macro-economic uncertainty conditions, and evaluates if strategies based on time diversification can be formed using these equity market anomalies. Market anomalies were tested using four major asset pricing models – the Capital Asset Pricing Model, the Fama-French three-factor model, the Carhart model, and the Fama-French five-factor model. Macro-economic uncertainty was tested using two proxies, namely VIX and default premiums. Time diversified strategies were examined by estimating Sharpe ratios of combined portfolios formed by combining winner univariate portfolios. Value effect in Germany, Size effect in France and Profitability effect in Italy and Spain provide the highest unadjusted returns on long side strategies. No significant reversal of these anomalies was found under different macroeconomic uncertainties. Asset pricing tests show that CAPM works well for Spain and Italy, while Carhart’s model explains returns in Germany. The Fama-French five factor model does not seem to be a good descriptor of asset pricing for data. No suitable model for explaining asset returns is identified for France. Finally, it is observed that some of the equity market anomalies seem to be countercyclical and therefore provide time diversification opportunities. The study has implications for academicians, investors, and policy makers by providing insights for developing profitable investment strategies and highlighting the efficacy of alternative models as performance benchmarks

Effect of Elevated Temperature on Diverse Properties of Concrete Containing Waste Materials

195-211Among the growing industries around the globe, concrete industry has been contributed significant role to the national economy. The most widely used construction material and the second-most consumed material in the world after water is concrete, which has been employed as insulation in applications involving high temperatures. This extensive review has been highlighted the best possible extracts from the literature on the assessment of thermal effects on various properties of concrete containing various waste products, in particular. Few enhanced performance after being subjected to high temperatures have been reported when industrial by-products are replacing conventional ingredients. Various mechanical properties of concrete after exposure to elevated temperatures have been recapitulated and reviewed. Effect of elevated temperature on many significant physicochemical, mechanical, microstructural changes in concrete made with various materials such as waste slags, recycled coarse and fine aggregates, silica fume, fly ash, crumb rubber, etc. have been vividly summarized and compared. Better performances for concrete incorporating recycled aggregates under exposure to elevated temperature have been reported from the results. Finally, the authors have made an attempt to summarize the short-comings in the specific field of research and discussed on available future scopes on utilization of various industrial by-products in sustainable concrete production under elevated temperature

CHARACTERIZATION AND DEVELOPMENT OF ECO-FRIENDLY CONCRETE USING INDUSTRIAL WASTE – A REVIEW

At present in India, about 960 million metric tons of solid was te is being generated annually as byproducts during industrial, mining, municipal, agricultural and other processes. Advances in solid waste management resulted in alter native construction materials as a substitute to traditional materials like bricks, blocks, tiles, aggregates, ceramics, cement, lime, soil, timber and paint. To safeguard th e environment, efforts are being made for recycling different wastes and to utilize th em in value added applications. The cement industries have been making significan t progress in reducing carbon dioxide (CO 2 ) emissions through improvements in process technology and enhancements in process efficiency, but further improvements ar e limited because CO 2 production is inherent to the basic process of calcinations of limestone. In the past two decades, various investigations have been conducted on industri al wastes like flyash, blast furnace slag, Silica fume, rice husks and other industria l waste materials to act as cement replacements .This paper consist of a review extensively conducted on publications related to utilization of waste materials as cemen t replacement with an intention to develop a process so as to produce an eco-friendly concrete having similar or higher strength and thus simultaneously providing a remedy t o environmental hazards resulting from waste material disposal

Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated

RETROFITTING OF REINFORCED CONCRETE BEAMS USING FIBRE REINFORCED POLYMER (FRP) COMPOSITES - A REVIEW

Rehabilitation and strengthening of old structures using advanced materials is a contemporary research in the field of Structural Engineering. During past two decades, much research has been carried out on shear and flexural strengthening of reinforced concrete beams using different types of fibre reinforced polymers and adhesives. Strengthening of old structures is necessary to obtain an expected life span. Life span of Reinforced Concrete (RC) structures may be reduced due to many reasons, such as deterioration of concrete and development of surface cracks due to ingress of chemical agents, improper design and unexpected external lateral loads such as wind or seismic forces acting on a structure, which are also the reasons for failure of structural members. The superior properties of polymer composite materials like high corrosion resistance, high strength, high stiffness, excellent fatigue performance and good resistance to chemical attack etc., has motivated the researchers and practicing engineers to use the polymer composites in the field of rehabilitation of structures. This paper reviews fourteen articles on rehabilitation of reinforced concrete (RC) beams. The paper reviews the different properties of Glass Fibre Reinforced Polymer (GFRP) and Carbon Fibre Reinforced Polymer (CFRP) composites and adhesives, influence of dimensions of beams and loading rate causing failure. The paper proposes an enhanced retrofitting technique for flexural members and to develop a new mathematical model

Microbial repairing of concrete & its role in CO2 sequestration: a critical review

Abstract Background Being the most widely used construction material, concrete health is considered a very important aspect from the structural point of view. Microcracks in concrete cause water and chlorine ions to enter the structure, causing the concrete to degrade and the reinforcement to corrode, posing an unacceptable level of structural risk. Hence repair of these cracks in an eco-friendly and cost-effective way is in the interest of various researchers. Microbially induced calcite precipitation (MICP) is an effective way considered by various researchers to heal those concrete cracks along with an important environmental contribution of CO2 (carbon dioxide) sequestration in the process. Main content As the current concentration of CO2 in the earth’s atmosphere is about 412 ppm, it possesses a deadly threat to the environmental issue of global warming. The use of bacteria for MICP can not only be a viable solution to repairing concrete cracks but also can play an important role of CO2 arrestation in carbonate form. This will help in carbon level management to lessen the adverse effects of this greenhouse gas on the atmospheric environment, particularly on the climate. To overcome the insufficiency of studies concentrating on this aspect, this review article focuses on the metabolic pathways and mechanisms of MICP and highlights the value of MICP for CO2 arrestation/sequestration from the atmosphere during the process of self-healing of concrete cracks, which is also the novelty of this work. An overview of recent studies on the implementation of MICP in concrete crack repair is used to discuss and analyse the factors influencing the effectiveness of MICP in the process, including various approaches used for CO2 sequestration. Furthermore, this investigation concentrates on finding the scope of work in the same field for the most effective ways of CO2 sequestration in the process of self-healing cracks of concrete. Conclusion In a prospective study, MICP can be an effective technology for CO2 sequestration in concrete crack repair, as it can reduce adverse environmental impacts and provide greener environment. This critical study concludes that MICP can bear a significant role in arrestation/sequestration of CO2, under proper atmospheric conditions with a cautious selection of microorganisms and its nutrient for the MICP procedure. Graphical Abstrac