Suitability of using novel cementitious materials for concrete constructions

Dare, Adedayo A. (2008) Suitability of using novel cementitious materials for concrete constructions. (MSc(R) thesis), Kingston University, .

Abstract

There has been much need for environmentally friendly and economical housing in war torn and natural disaster areas of the world. People are left homeless and the government needs to tackle the cost of resettling those displaced by these unforeseen circumstances. Providing adequate housing in these situations will not only protect people from the physical environment but can also contribute towards better health and reduce the incidence of disease. Given the scale and nature of the issue, many alternative housing systems need to be considered to ensure appropriate choices are being made for a particular situation. In this', project, suitability of a lightweight concrete material has been assessed. The material considered is Expanded Polystyrene Beads (EPS) used as an aggregate replacement in concrete production. An extensive experimental work design aspects based on BS 8110: Part 1 was considered. The use of polystyrene beads as an alternative aggregate is seen as a viable alternative to conventional concrete aggregates especially in naturally disaster prone and war torn countries of the world, due to its potential performance and variety of applications. At the start, the project examined key properties of polystyrene bead uses and then used the findings to develop a design procedure, followed by comments on its application in the future housing needs meeting sustainability requirements. A wide range of raw materials were used in the premix experiments and each product has its own particular requirements. However, these rules were considered in mixture design. 1. The water content was kept low 2. Using an adequate fibre content about 3% volume 3. Maintaining a sand/cement ratio not less than 0.67 Initially, the premixes were based on the following assumptions; A trial mix of 1: 1:4 = 6 units of concrete. 14 liters = 1 unit. Based on the assumptions, the following weights of materials were used in the premixes and standard mixes depending on the mix proportions. Cement 1 Sand 1 EPS beads 4 [Table] The preparation of the premixes were carried out in two stages in order to get a workability of the wet concrete and appearance of the final composite. To produce a premix of the correct quality, the mixing was done in two standard stage processes. The results obtained in the studies indicated that EPS concrete strength and density can be enhanced by varying the mix proportions of the material constituents (cement, sand and polypropylene fibre), meeting specific requirements. Furthermore EPS concrete strength gains at early stages, in 7days which is about 70 -80% of its 28 day strength comparable to conventional concrete. It is concluded that these results have corroborated earlier reports on the use of EPS beads as viable alternative aggregate in concrete. EPS concrete will therefore conform to building codes of practice and regulations. On the whole, the use of Expanded Polystyrene Beads in the building industry could bring a lasting solution to the problem of mass housing in both first and third applications.

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