Key Engineering Materials Vol. 678

Abstract: Thermal insulation material is an important component to reduce the environmental impact of buildings through the reduction of energy consumption in the operation phase. However, the material itself has embodied environmental impacts for the value it provides. Eco-efficiency is a method that quantifies relation between the environmental performance and the created value of a product system. This study investigated contributing factors of the eco-efficiency of thermal insulation materials to support decision making of material manufacturers. For the improvement of eco-efficiency, the assessment was made in two scopes: investigating the contributing factors of impact caused at production processes; and thermal performance through thermo-physical properties. For quantifying environmental impacts, cradle-to-grave life cycle assessment (LCA) of each materials were made. The life cycle impact assessment (LCIA) indicators used were ReCiPe H/A and global warming potential (GWP100a). For the assessment of production process, the inventories of the materials were assigned to six categories: heat, chemicals, electricity, transportation, raw materials and wastes. Among the assessed materials, contribution of electricity and heat within the production process was large for foam glass which had the highest potential to improve the eco-efficiency which was by factor 1.72. The analysis on relation between thermo-physical properties and eco-efficiency based on product data of the materials highlighted the importance of density as an indicator upon development and use. Althoughdensity often gains less attention,the finding suggested the effectiveness of improving the efficiency by having lower density without compensating the performance of the materials.

Abstract: This chapter shows the most recent and innovative contributions and research trends arounbd the wide issue of energy efficiency in buildings by means of passive techniques, such as new effective materials for building envelope optimization. In particular, cool materials will be dealt with by considering their capability to keep a surface cooler than other solutions when exposed to solar radiation. Then multifunctional materials such as thermal and acoustic insulation panels will be analyzed. Finbally, natural and biobased solutions for energy saving will be investigated. Each one of these topics will be studied by elaborating a first general assessment of each technique and then by analyzing the most recent contributions and research trends in order to provide a wide perspective of the question that is going to be addressed in this chapter.

Abstract: History itself is the evident that from the years together the people moves to the region where they can satisfy their needs and wants with fewer efforts and more opportunities. This thought lead to accumulation of people in some areas resulting in urbanization. As this urban area contributes highly in nation’s economy even the government announce a far reaching program of investments in urban development. However, these urban agglomerations manifest generally unsustainable ecologies. The depletion of material resources, the accumulation of waste, and the over-expenditure of non-renewable energy are direct consequences of the predatory expansion of urbanization. Out of this the major contribution goes to construction industry as the data reveals that Construction is responsible for 40% of the total world flows of raw materials such as sand, gravel& clay. It takes one quarter of all virgin wood, 40% of energy use,16% of water withdrawals,& produces 17% of all waste generated. This problems can be tackle efficiently it the waste generated by industries can be reuse for the purpose of making construction material. With little logic and application of basic science the new material that can be made by mixing waste may prove energy efficient if its thermal resistivity is enhanced and utilized. The research over here is a paradigm of such two waste mix building component with high thermal resistive property. The paper is about the making and testing of waste mix tiles and filler blocks so as to find its efficiency in construction practices. The results obtained shows that by adopting such materials for construction purpose will reduce amount of operations energy consumption as well as reduce consumption of non – renewable resources and would help to utilize waste in fruitful way. The effort in this research are thus to find energy efficient construction material.

Abstract: This work aimed to measure the hygrothermal properties of some different straw-based mix that could be used as building materials (panels or bricks). Straw is used to improve the hygrothermal performances of the final products. Several mix were produced adding different percentages of straw. Two types of fibers were used: wheat straw and bean straw. The results indicated that increasing the percentages of straw greater effects on the change of thermal properties can be appreciated. Furthermore the results also reveal that the specimen produced by water glass and straw, without binder, has the highest values of hygric properties and thermal insulation.

Abstract: Clayish earth-based mortars can be considered eco-efficient products for indoor plastering since they can contribute to improve important aspects of building performance and sustainability. Apart from being products with low embodied energy when compared to other types of mortars used for interior plastering, mainly due to the use raw clay as natural binder, earth-based plasters may give a significant contribution for health and comfort of inhabitants. Due to high hygroscopicity of clay minerals, earth-based mortars present a high adsorption and desorption capacity, particularly when compared to other type of mortars for interior plastering. This capacity allows earth-based plasters to act as a moisture buffer, balancing the relative humidity of the indoor environment and, simultaneously, acting as a passive removal material, improving air quality. Therefore, earth-based plasters may also passively promote the energy efficiency of buildings, since they may contribute to decreasing the needs of mechanical ventilation and air conditioning. This study is part of an ongoing research regarding earth-based plasters and focuses on mortars specifically formulated with soils extracted from Portuguese ‘Barrocal’ region, in Algarve sedimentary basin. This region presents high potential for interior plastering due to regional geomorphology, that promote the occurrence of illitic soils characterized by a high adsorption capacity and low expansibility. More specifically, this study aims to assess how clayish earth and sand ratio of mortars formulation can influence the physical and mechanical properties of plasters. For this assessment four mortars were formulated with different volumetric proportions of clayish earth and siliceous sand. The results from the physical and mechanical characterization confirmed the significantly low linear shrinkage of all the four mortars, as well as their extraordinary adsorption-desorption capacity. These results presented a positive correlation with mortars ́ clayish earth content and are consistent with the mineralogical analysis, that confirmed illite as the prevalent clay mineral in the clayish earth used for this study. Regarding mechanical resistance, although the promising results of the adhesion test, the flexural and compressive strength results suggest that the mechanical resistance of these mortars should be slightly improved. Considering the present results the mortars mechanical resistance improvement may be achieved through the formulation of mortars with higher clayish earth content, or alternatively, through the addition of natural fibers to mortars formulation, very common in this type of mortars. Both those options will be investigated in future research.

Abstract: In the present study effect of different plasters like cement plaster, mud, cow dung and coatings like paint, hydrated lime, charcoal on the thermo – physical properties such as thermal conductivity, overall thermal transmittance, resistance of Light Weight Blocks (LWB) using pond ash has been evaluated. Result of the study state that, cow dung is the best amongst all other plasters used. Cow dung increases thermal resistance of Light Weight Block (LWB) from 0.391 to 0.505 m²K/W. Thermal resistance increased by using other plasters lies between 0.391 to 0.505 m²K/W. The study of curing of LWB from 56 days to 90 days has been made and it is found that thermal conductivity is reduced by 5% and thermal resistance is increased by 3% comparing the duration of curing from 56 to 90 days. Further, effect of activator on the compressive strength & demolding time has also been studied. When activator is used, there is an increase in compressive strength at 56 & 90 days at all levels of replacement when compared to without activator. Reduction in demolding time from 48 hrs. varies between 6 – 12 hrs.

Abstract: Rigid polyurethane foam (RPUF) is typically prepared by the reaction of an isocyanate, such as methyl diphenyl diisocyanate (MDI) with a polyol blend. During the polymerization reaction, a blowing agent expands the reacting mixture. The finished product is a solid, cellular polymer with a high thermal resistance. RPUF is an outstanding material for different applications. It has many desirable properties such as low thermal conductivity, low density, low water absorption, low moisture permeability, excellent dimensional stability, high strength to weight ratio. So, it is the best insulating material for industrial buildings, cold storages, telecom and defense shelters due to low thermal conductivity, low density, low moisture permeability and high porosity. It works to reduce heating and cooling loss, improving the efficiency of the building envelope. Thus, RPUF insulation in building envelopes brings additional benefits in energy savings, resulting in lower energy bills and protecting the environment by cutting CO2 emissions.

Abstract: The utilization of waste materials in concrete is one of the best value added solutions to the construction industry. With the aim of sustability development, high volume fly ash (HVFA) were tested in concrete by substituting 40, 50 and 60% of OPC with fly ash. Properties studied in this research includes fresh concrete properties, mechanical properties and the resistance of concrete exposed to high temperature. The test result indicates that HVFA concrete positively influenced the workability; however, the setting times of the concrete were longer. It has been found that the development of strength of high volume fly ash concrete was relatively slower, but ahigher strength development at later ages was observed in concrete containing HVFA. The performance of concrete at elevated temperatures reveals that concrete without any fly ash has better resistance than HVFA concrete at high temperature. The use of high volume fly ash results in an acceptable concrete performance, which grants high potential for energy saving in the building construction.

Abstract: Reinforcement corrosion is one of the main causes of concrete deterioration. The steel in concrete is naturally protected from corrosion by the presence of a passive film formed through the high alkalinity of concrete. A technique to improve the protection of steel in concrete is the inclusion of mineral additions. Natural pozzolan (NP) from Beni-Saf is a mineral addition that is abundant in western Algeria. The experiment was conducted on mortar specimens, containing steel bars and exposed to the aggressive solutions of Na₂SO₄ and MgSO₄. The status of reinforcement is periodically monitored by measuring the electrochemical potentials and the corrosion rates by the technique of linear polarization resistance (LPR) and also the thermal conductivity was evaluated. The test results show that natural pozzolan significantly affects the physical properties of mortars, improves the corrosion resistance of mortars containing up to 20% of natural pozzolan and reduces the thermal conductivity.