Papers by Keyword: Cost Effectiveness

Abstract: The paper describes how two traditional construction materials-Concrete and Steel Reinforcement can contribute better value to RCC and Precast Concrete structures by modernizing their forms as Self-Compacting Concrete (SCC) and Welded Wire Fabric (WWF). SCC is widely accepted by infrastructural, industrial, commercial and even individual house builders – due to its assured quality delivery, especially for cast–in-situ RCC construction. Many defects with conventional vibrated concrete -- honeycombing, segregation and bleeding, loss of workability, choking in concrete pump pipelines and overheating -- have been eliminated or at least minimized by using SCC. For any type of congested reinforcement, mainly in beam – column junctions, edges and corners, SCC has delivered satisfactory filling and honeycomb free densification. Also due to the absence of the use of vibrators, formworks have been spared from joint leakages – saving both the concrete and the formwork itself. But however, even in many advanced construction companies, due to poor detailing practices, and non-mechanized bar-bending (or mechanization limited to only cutting and bending of rebars ), reinforcement laps, splices and bends, hooks, pose an additional burden on the free flow, filling and densification of SCC. Thus using SCC alone may not ensure defect free construction in RCC. The changes should be wholesome and comprehensive. This paper describes how SCC and WWF enhance the quality of RCC construction and ensuring defect free construction. The effects of WWF and SCC are elaborated in detail considering all the physical properties and practical issues. Along with the technical analysis, the commercial and sustainable benefits of SCC and WWF are discussed.

Abstract: This article describes the applications and benefits of a recently developed smart building material namely Engineered cementitious composite (ECC), also known as flexible or bendable concrete. Conventional concretes have a strain capacity of only 0.1 percent and are highly brittle and rigid. This lack of bendability is a major cause of failure under strain and has been a pushing factor in the development of an elegant material which is capable to exhibit an enhanced flexibility. An ECC has a strain capacity of more than 3 percent and thus acts more like a ductile metal rather than like a brittle glass. The aim of this paper is to highlight a probable success of ECC in terms of industrial and commercial use in Pakistan. With the introduction of flexible concrete in building technology, it is likely to have safer and more durable construction. The material is expected to display reduced detrimental impacts on the natural environment. A bendable concrete is composed of all the ingredients of a traditional concrete minus coarse aggregates or crushed stones and is reinforced with micromechanically designed polymer fibers. The mechanism of action of the micro-polymeric fibers in concrete has also been emphasized. The principles of mix designs of the mortar incorporating fibers to make an ECC have also been explained. It has also been mentioned in detail as how this technology can be used to enhance the flexibility of some modern concrete types like flowing concrete, self-compacting concrete, and lightweight concrete. ECC is a green construction material. The possible benefits like environment friendliness, cost effectiveness, and durability have been also been elucidated in the paper.

Abstract: This paper examines the production of calcite and calcite-cement stabilized laterite hollow blocks as low-cost masonry units. First, is the production of laterite hollow blocks solely stabilized with finely ground limestone or calcite followed by the production of laterite hollow blocks stabilized with calcite-cement composite. Laterite was sourced from three locations: Asoro, Evbuotubu and Ugbowo. Blocks were produced using a specially constructed machine with percentages of calcite and calcite-cement content varying from 4% to 16% respectively at compactive pressures of 10.32 and 13.75N/mm2. Equal amounts of calcite and cement are used in the composite. The blocks were then tested for 7, 14 and 28 days strengths after curing. The results show that laterite blocks stabilized with calcite alone do not satisfy the Nigerian Industrial Standards or British Standards for blocks but those stabilized with 8% calcite-cement content, i.e., 4% calcite with 4% cement do, at moulding pressure of 13.7 N/mm2. Based on the local cost data, the results also show that calcite-cement stabilized laterite hollow blocks are 17% cheaper than an equivalent cement-stabilized hollow block and 46% cheaper than the low quality sandcrete blocks sold in the market.