Key Engineering Materials Vol. 650

Abstract: The conventional building material used in the construction industry in India is the burnt clay brick which has high embodied energy (1.4W/m K). It causes significant environmental hazards as it consumes considerable amount of top soil. Hence there is a need to produce environmentally responsive building materials for the construction of new buildings in order to meet the rapid urban growth. As an alternative, natural resources used in conventional building material can be replaced by industrial and agricultural wastes like fly ash, copper slag and phosphogypsum, slag to address and solve socio-economic problems such as employment, shortage of residential spaces while ensuring the economic feasibility. This paper thus attempts to identify an eco-friendly alternative building material by utilizing wastes from industrial & agricultural sites as partial substitutes of sand, cement or aggregates, thereby reducing continuous exploitation of these natural resources. . The properties of the alternative building wall materials are identified and compared with that of conventional bricks. Additionally the thermal conductivity of the proposed block is determined and compared with that of brick to provide a comfortable building environment for the end user.

Abstract: Construction industry is one of the largest consumers of the natural resources and responsible for substantial amount of CO₂ emission in the world. The purpose of this paper is to carry out comprehensive literature review on the low embodied energy materials and techniques used in the existing and / or new buildings in India. The paper also compares the conventional building materials and techniques, with alternative ones to assess their superiority. An investigation into the energy consumed by the building materials and techniques is computed to find out the embodied energy requirements to prove superiority of innovative construction techniques over traditional materials.

Abstract: In a number of countries, important research projects are nowadays carried out and are mainly devoted to developing original approaches to sustainability in order to improve the lifetime of reinforced concrete structures. This paper describes an innovative use of plastic bottle waste as cement-substitution within composite materials for preventing chemical attacks, energy efficiency in buildings or repairing various reinforced concrete structures. So, experiments were accomplished on polymer-mortar composite materials where the cement was partially replaced by various volume fractions of waste polyethylene terephthalate (PET) particles (0%, 6%, 12% and 17%). The specimens were tested by destructive and non-destructive testing and for chemical resistance to acid solutions at different concentrations. From this study, it was found that the PET-modified mortars exposed to aggressive environments showed better resistance to chemical attack than unmodified one without substantially affecting the mechanical strength in tap water and UPV values decrease as the proportion of PET waste in the mix increases. The addition of PET to the modified mortars, means reducing the penetration of aggressive agents. The formations which appear such as different calcium salts were determined by TG/dTG analysis. So, these composite materials are often used as low-cost materials for energy efficiency in buildings, preventing chemical attacks or repairing various reinforced concrete structures exposed to aggressive environments where high resistance to acid is required and to both reduce sound intensity and dampen vibrations.

Abstract: Numerical simulation studies are carried out for improvement of energy efficiency in a room by with different thermal insulating materials using computational fluid dynamics (CFD). The study considered various building insulating materials (BIM’s) such as: (a) Expanded Polystyrene (EPS) (b) Fiber Glass (Resin bonded (RB)-Glass wool) (c) Polyurethane Foam (PUF) and (d) Cement Plaster (CP) along with composite bricklayer combination. A multi-physical 3D model room of size 2.6 m × 2.6 m × 2.6 m is created to analyze the performance of different insulating materials using CFD simulations. The experimental data of 24 hr temperature cycle of the ambient air is used for the analysis of performance of thermal comfort inside the room with the incorporation of different thickness of the insulating materials. The thickness of insulation 0.03, 0.1, 0.2 and 0.3 m is applied on interior side of walls and roof of the building. The study performed with different grid sensitiveness for coarse, medium and fine meshes for the improvement in the accuracy of the results. The fine grid mesh analysis is chosen to carry the further studies to compare the insulated and non-insulated condition for the thermal behavior inside the room. The result shows that the thermal conductivity and heat capacity of insulated walls are very important to be taken into account for carrying out detailed thermal analysis of buildings. The studies are carried out using commercial CFD tool of ANSYS CFX 15.0. The results of comparison shows that it is possible to maintain needed thermal comfort conditions in the room while reducing the total energy consumptions at the same time by appropriate use of BIM’s.

Abstract: With the rapid development and modernisation, cities are growing at a very fast pace and the buildings are the main component of cities. Building construction in the world annually consumes around 25% of the global wood harvest, 40% of stone, sand and gravel and 16% of water. It generates 50% of global output of GHG and agents of acid rains. The manufacturing process of building material contributes to Green House Gases such as CO₂ to the atmosphere to a great extent. The natural disasters like global warming, ozone layer depletion, unexpected seasonal variations and decreasing land surface have now moved the centre of attraction from development to sustainable development. Since we have limited resources and energy, our development should focus on conserving the energy. Due to the continuous exploitation of natural resources, there is an urge to produce environmentally responsive building material for the construction of new buildings to meet the rapid urban growth. Sustainable buildings are designed, constructed, maintained, rehabilitated, and demolished with an emphasis throughout their life cycle on using natural resources efficiently while also protecting global ecosystems. Selection of appropriate building material helps to use the energy efficiently. In the rapidly changing scenario of building sector, planners, architects, engineers and builders are looking for new materials and technologies to adopt in future constructions that benefits like energy efficiency, resources and water conservation, improved indoor air quality, life cycle cost reduction and durability. This paper presents a brief study of sustainable aspects of building materials and a tool for Life Cycle Assessment criteria that helps in selecting proper building materials.

Abstract: Municipal solid waste incineration bottom ash (IBA) has great potential to be utilized for civil engineering applications. This paper is to investigate the characteristic of gas generation from IBA and to study the potential of IBA as aerating agent to replace costly aluminum powder and as silica source to partially replace silica flour/fly ash in the production of autoclaved aerated concrete (AAC). Results show the aeration capacity of IBA used in this study is about 1% that of pure aluminum powder by mass. Finer particles, higher alkali molarity, and higher reaction temperature encourage the reaction and more gas is generated per gram of IBA. Type of alkaline solution does not seem to be an important factor for gas generation from IBA. Several exemplary lightweight mortars and AACs were produced by incorporating IBA as aerating agent. It is highly plausible IBA can be used as aerating agent to replace pure aluminum powder in the production of normal aerated concrete. IBA-AACs with density ranging from 600 to 800 kg/m³ were successfully synthesized by using IBA as aerating agent. For a given density, the compressive strength of IBA-AAC is higher than that of AAC due to the formation of more uniform pore structure with smaller pore size in IBA-AAC.

Abstract: Buildings are responsible for at least 40% of the used energy in most of the countries and the figure is rising as the construction booms. But pace of energy saving in building is much lower in India as compared to developed countries. So, there is an immediate need to open up new techniques to address the issue and also progress in the area of actual implementation should be accelerated immediately because both knowledge and techniques are available today to slash the energy usage in a building.Our focus is mainly on the modification of building envelope to reduce the energy used for cooling in A/C building and to reduce the temperature of the interior of non-A/C building.Berger has developed different systems such as EIFS for wall, Roof insulation and Heat reflecting paint for both wall & roof. The efficiency of these systems in terms of energy saving and cooling has been tested at Howrah and also has been tested by CBRI at Roorkee, through actual field study for two years. The test results revealed that the maximum energy saving of 32.33% can be achieved for A/C building. For non A/C building, maximum temperature difference of 6.4°C between outdoor and indoor air of the room can be achieved.

Abstract: The climatic conditions in a man-made urban environment may differ appreciably from those in the surrounding natural or rural environs.... each urban man-made buildings, roads, parking area, factories......creates around and above it a modified climate with which it interacts [1].Outdoor thermal comfort has gained importance in thermal comfort studies especially in tropical countries. In country like India, culturally the activities are spread both indoors and outdoors. Therefore the need for ambient outdoor environment gains importance. As there are many factors that contribute to outdoor thermal comfort (climatic factors and physical factors), this study aims in analyzing the impact of building material contribution, in an institutional courtyard. In order to understand the thermal contribution of various building materials and to suggest material choice to designers, ENVIMET is used for simulation purpose. The outdoor thermal comfort index employed in this study is PET (Physiological Equivalent Temperature), calibrated using RAYMAN.

Abstract: Every year, millions of cube meters are dredged from dams and restraints as an entertaining and prevention procedure all over the world. These dredged sediments are considered as natural waste leading to an environmental, ecological and even an economical problem in their processing and deposing.Nevertheless, in the context of the sustainable development policy, a way of management is opened aiming to the valorization of sediments as a building material and particularly as a new binder that can be industrially exploited and that improve the physical, chemical and mechanical characteristics of the concrete.This study is a part of the research works realized in the civil engineering department at the university of Mostaganem (Algeria), on the impact of the dredged mud of Fergoug dam on the behaviour of self-consolidating concrete in fresh and hardened state , such as the mechanical performance of SCC and its impact on the differed deformations (shrinkage). The work aims to valorize this mud in SCC and to show eventual interactions between constituents. The results obtained presents a good perspectives in order to perform SCC based in caclined mud.