Papers by Keyword: Low Thermal Conductivity

Abstract: This research studies on the possibility of producing a more sustainable lightweight brick. Solid waste bottom ash (SBA) and lime found in area of Ratchaburi province of Thailand were mixed into the composite brick for the replacement of fine aggregates and Portland cement contents, respectively. Effects of varied amount of SBA and local lime contents typically (10, 20, 30, 40 and 50% by weight) on mechanical and physical properties of bricks were studied. Results showed that with the replacement cement and fine aggregate of 20% by weight with SBA and local lime, respectively showed the maximum values. Similarly, the thermal conductivity and density and product weight showed the maximum values at the same replacement contents. By conclusion, this application may be an interesting solution in order to improve sustainability and energy efficiency of the low cost house in local area of Thailand.

Abstract: This research studies on the possibility of producing a more sustainable lightweight brick. Natural cellulose fibre produced from leaf and wood aggregates, lime and soil from local area of Thailand were added into the brick with minimizing Portland cement content. Effects of varied amount of cellulose fibre contents typically (10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 %) on mechanical and thermal properties of bricks are studied. Mechanical performances have been investigated with compressive, flexural strength and thermal conductivity of the samples. Also, the Leachate Extraction Procedure is observed. Results showed that adding more cellulose fibre contents can reduce the thermal conductivity, density including the compressive and flexural strength of the brick. On the other hand, the water absorption increases. It is also shown that the composite bricks can add fibre contents up to 55% by weight that can be used as non-load bearing concrete masonry units considered by the compressive strength. By conclusion, this application may be an interesting solution in order to improve sustainability and energy efficiency of the low cost house in local area of Thailand.

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: This work presents a study on the investigation of recycled waste tyre (crumb rubber) as aggregate in the combination of local soil-cement brick. The purpose is to develop a lightweight brick with low thermal conductivity that can produce as low cost materials in local area of Thailand. The different amount of crumb rubber particles at 0, 10, 15, 20, 25, 30 and 40% were replaced to local Ratchaburi soil by weight and then mixed with a constant of Portland cement content at 10%. The mechanical properties were studied and indicated that a significant reduction in sample unit weight, there by resulting in a reduction of compressive strength and flexural strength. The results show that the presence of air voids and crumb rubber particles in the matrix can increase the water absorption but decrease the thermal conductivity. However, according to ASTM indicates that this hybrid material can be used as non-load bearing concrete masonry units (2.45 MPa) and is also suitable for construction as low cost and low energy consumption house in Thailand.

Abstract: Porous mullite ceramics were prepared using an industrial grade mullite powder by foaming and starch consolidation method. The influence of solid loading of suspension and sintering temperature on the porosity of samples was evaluated. The sintered mullite ceramic with porosity from 73 to 86 vol% contained the microstructure with spherical pores and a larger mean pore size. Thermal conductivity measurements were carried out by the hot-disk technique at room temperature resulted in values as low as 0.09 W/(m·K).

Abstract: Non-shrinking composite silicate insulation material has advantages of low drying shrinkage, density, thermal conductivity and good thermal insulation which withstands high temperature and militates in favor of specially shaped structural member construction, etc. This article describes raw materials and the production process of the above material, discusses thermal insulation characteristics, technical performance and the features of use and particularizes the application effect in the project.

Abstract: Effect of adding CaCO₃ on the microstructure and properties of corundum was studied, with corundum modified by adding CaCO₃ powder, by means of XRD, SEM etc. The experimental results show that when the quantity of CaCO₃ powder is not more than 14.1wt%, would obtain corundum-calcium hexaluminate composite aggregate. When a little hexaluminate is generated, it would not increase porosity significantly but closed porosity increase slightly, and the heat conductivity is lower than tabular corundum. Calcium hexaluminate in aggregate grow well and are flakes. There are large numbers of small pores, and distributed uniformly. Composite aggregate has preferable performance of sintered and low thermal conductivity when hexaluminate generative capacity is about 27%.

Abstract: An optimal air-entraining agent was selected through a systematically experimental and theoretical study on air-entraining and full-light-aggregate concrete (AEFLC) for structural and thermal insulating wall. Among the three air-entraining agents: rosin acid sodium, Polycarboxylate-type agent, Lauric acid-based agent, Lauric acid-based (Huntsman) air entraining agent was considered the best for the air-entraining quantity and quality. As the result, a AEFLC with the apparent density of 1110kg/m3, compressive strength of 18.8MPa in 28 days, and thermal conductivity of 0.38w/(m.K) was obtained.

Abstract: The development of new alternative type of fly ash bricks using the locally available local soil from Ratchaburi province were mixed with fly ash from Kanchanaburi province, where both sources in western of Thailand, is the main purpose of this study. These are compared to the ratchaburi local soil cement bricks without the mixing of western fly ash in different proportions. It is concluded that the addition of western fly ash reduces the thermal conductivity. The compressive and flexural strength decrease when the ratio of western fly ash is more than 30 percentages. However, considering the various factors it can be concluded that appropriate ingredient toward producing the good commercial western fly ash bricks is 5 percentages of portland cement and 30 percentages of western fly ash by weight basis of ratchaburi local soil. The compositions of western fly ash at more than 25 percentages by weight basis of ratchaburi local soil and since up to 14 days of curing time are proved to be economical mixtures for load bearing panels or brick type structural elements according to the Thai Industrial Standard for structural clay load-bearing tile.

Abstract: Machining is gradually giving way to alternative manufacturing methods for titanium components. Although powder metallurgy based methods are more complicated and expensive, they are gaining more ground because of the difficulty of machining titanium due to its low thermal conductivity. Moreover documented information on research works on titanium remains so limited in comparison with steel and aluminium. This paper highlights the importance of titanium based alloys, its properties and areas of application as well as its major classifications. A typical case of semi-finish turning of α-titanium BT5 alloy is also presented. Results of chip root examination based on the application of a quick-stop mechanism with about 11m/s withdrawal speed to freeze the cutting operation is also presented, thereby highlighting some main features that are peculiar to the chip formation in titanium as compared with other materials.