Volume 3 Issue 2
Authors: Radhakrishna Radhakrishna; Sasalatti Vinod. M.; Venugopal K; Venu Madhav Tirupathi
Abstract: Despite the extensive developments in the construction industry, cement concrete still remains as the major and popular building material. The main drawback of cement composites is the deterrent to sustainability. As an alternative, new materials are to be developed which can completely replace traditional cement without compromising the strength and durability. In the present investigation of alternative binders, geopolymer and FaL-G were developed to traditional cement. Both the binders were used to develop masonry units and concrete. Phenomenological models were advanced to develop mix proportion for the masonry blocks and concrete. The pattern of strength variation was found to be in accordance with generalized Abrams’ law at various fluid-to-binder ratios (FBR). The strength data was further analyzed within the framework of generalized Abrams’ law, which has already been validated for cement-based composites. To formulate the phenomenological model, the strength data at a specific binder-to-fluid ratio was identified as reference value. The strength ratio used in the phenomenological models reflects the synergy between different ingredients in the microstructure of the composites. The validity of phenomenological model thus developed was examined with an independent set of experimental data generated at reference state and the same set of values were used to find the strength development at any other FBR and compared with actual values. Heat cured geopolymer, ambient cured geopolymer, and FaL-G blocks were considered in this paper.
Keywords: Fly Ash; Geopolymer; FaL-G; Compressed Blocks; Fluid-to-Binder Ratio; Abrams’ Law; Phenomenological Model
Authors: P. S. Kwawukume; Albert Essuman; P. S. Kwawukume Jnr
Abstract: A redesigned downdraft kiln for ashing cocoa pod husk in cocoa growing areas of Ghana was calculated using three-layer brick wall structure derived from thermal conductivity calculations yielding outer wall temperature of 85 oC capable of withstanding cyclical heat and cold temperatures without shelter over the structure. All calculations were based on the length of the bricks and their thermal conductivities. Activities on cocoa farms led to tons of leftover cocoa pod husks (CPH) as waste after harvest seasons when nearly all useful products have been extracted and sold to marketing boards. Farmers on their own have attempted to ash the CPH by bonfires but ended up unintentional bushfires, which even destroyed their farms As an improvement in bonfires, up-draft kilns were used but did not serve the purpose entirely due to technical problems in some elements of kiln design parameters that led to low quality of ash from high percentage of unburned husks. The approach used was the prototype design of down-draft kiln with three new features, namely, an dedicated chamber to provide heating fuel in the raining season when only the drying husks are required; an empty chamber in front of the chimney duct which eventually reduces the speed of hot air on escape through the chimney by natural draft principle and maintains a steady temperature in the main combustion chamber; the suspending metal grates with high density bricks which turn into the suspension brick platform. Compared with the unburned lumpy ash from the previous kilns, the re-designed kiln with drying and incinerating chambers produced good ashes throughout the year for industrial use.
Keywords: Cocoa Pod Husk (CPH); Kiln Design; Uniform Heat Distribution; Chimney Wall/ Height; Suspension Grate Design
Authors: Ryszard A. Daniel
Abstract: The quality of ambient air is an issue of growing concern, particularly in cities. In many parts of Europe, the most severe threat to this quality comes from intensive road traffic. This article presents some ideas of improving the air cleanness by isolating the heavy traffic at the most populated areas in the so-called “traffic ducts”. Modern technology makes it possible to realize such ducts in both new construction and improvement projects of roads and bridges. The materials that allow crossing frontiers in this field are fibre-reinforced polymers (FRPs. In this article, a number of possible traffic duct solutions employing FRPs are globally presented, followed by some general notes and predictions of future developments.
Keywords: Bridge Engineering; FRP Structures; Composites; PM Emissions; Air Pollution; Sustainability