Key Engineering Materials Vol. 650

Abstract: Reinforcement corrosion is caused either by chloride ions or carbonation, although chloride-induced reinforcement corrosion is the most widespread and serious problem. Moreover, the use of supplementary cementitious materials has been proposed in order to mitigate the durability problem, reduce the production costs and control the emission of greenhouse gases (GHGs). This paper reports the results of a study conducted to investigate the influence of Algerian natural pozzolan on reinforcement corrosion in blended cement mortars exposed to chlorides. Compositions, with replacement levels of 0, 10, 20 and 30% of normal Portland cement by mass of cement by natural pozzolan, were investigated. The exposure solution contained a fixed concentration of 5% sodium chloride. The compressive strength, corrosion potential, corrosion current density, sorptivity, rapid chloride ion penetration, in accordance with the standard ASTM C1202-12, were determined in order to characterize the mechanical and electrochemical behavior of the mortars. It was found that the use of natural pozzolan had resulted in a significant decrease in the corrosion rate of rebars, better mechanical performances and also a resistance to penetration of chlorides ions.

Abstract: EIL had carried out consequence modelling for catastrophic rupture of debutanizer reflux drum of FCC unit in Haldia refinery and analyzed the mitigation measures required. The catastrophic rupture may produce thermal radiation distances due to fireball of 12.5kW/m², which will be extending up to administrative building. It was recommended that any openings facing towards process unit should be blocked and protective measures to be taken to withstand thermal radiation of 12.5kW/m². Therein, extensive study was carried out on the properties of the AAC blocks and it was found that they are light weight, can withstand temperature below 3000⁰C without crumbling and have excellent fire resistance properties. Plate glass in a window can absorb some 40 to 60% of the radiation from a building fire and cannot be relied on to afford protection as large areas are liable to crack and fall out. Hence, glazed openings of the Administrative Building towards the Process Units were closed with AAC blocks of 125mm thickness. Apart from ensuring desired safety requirements and reducing spread of incident heat flux to internal parts of the building during a fire, this has also brought down the heat load on the air-conditioning system due to lower interior temperature.

Abstract: This paper investigates the sulfate resistance of blended cements produced by replacing 10, 20, and 30% of sulfate resisting cement (SRC) with Algerian natural pozzolan. Ordinary and blended cement mortar specimens were cast and immersed in a 5% sodium sulfate solution for 3 years. The sulfate resistance of mortars was evaluated by visual examination, compressive strength, mass change and diffraction (XRD), which was used to identify the degradation products formed by sulfate attack.The test results demonstrated that the sulfate resisting cement incorporating 10% of natural pozzolan was less susceptible to sulfate attack. In addition to improved performance, the results promise the production of a sustainable building material with environmental and economic benefits due to the reduced amount of overly-high-energy-consuming cement used and the potential reduction of the cost of sulfate resisting cement.

Abstract: Utilization of natural fiber as reinforcing material is the latest trend in polymer science to produce higher strength with lower weight composite materials having wide range of applications. As a natural fiber, banana fiber is getting importance in recent years in the reinforcement arena of polymer composite. Two species of banana viz Musa sapientum and Musa paradisica available in North East India were selected considering their higher fiber yield and adequate strength properties of the fibers. The chemical compositions, spectroscopic and thermal properties of these fibers were studied in order to study their suitability for commercial exploration. Low density polyethylene (LDPE)-banana fiber reinforced composites were prepared using hydraulic hot press. Physico-mechanical properties (e.g. tensile strength, flexural strength, elongation at break, Young's modulus) of the prepared composites were determined. The tensile strengths and flexural strengths of the composites increased while using LDPE 10 to 30 % of the fiber and then started to decrease gradually. Young moduli of the composites increased with the increase of fiber mass. Water absorption also increased accordingly with the increase of the fiber weight. The elongation at break decreased with increasing fiber quantity. The mechanical strength properties of chemically treated banana fiber-LDPE composites were slightly higher than the mechanically extracted fiber-LDPE composites. Structural analyses of the treated fibers were carried out by FTIR and XRD. These studied revealed due to the removal of noncellulosic constituents such as hemicelluloses and lignin the crystalline properties of the fibers were increased. All the properties of composite like tensile strength, flexural strength, water absorption capacity etc. plays a significant role in these polymer composite materials. Hence it can be concluded that banana fiber can be used as reinforced agent successfully in the composite industry as a sustainable building material.