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    PublicationEmbargo
    Effect of Surface Modification and Fibre Content on the Mechanical Properties of Coconut Fibre Reinforced Concrete
    (https://www.scientific.net/, 2020-09) Hettiarachchi, C; Tharmarajah, G
    . In the past few decades, concrete has been the most widely used material for structural applications in the world and uses steel reinforcement as aide to meet the flexural, tensile and ductility demands required of concrete structures. Manufacturing of concrete and steel reinforced concrete structures is associated with millions of tons of carbon dioxide emissions and mineral waste. This activity is also responsible for the depletion of a large number of non-renewable resources. Reinforcing steel is also a high cost material, consumes a lot of energy in its production. Consequently, the use of natural fibres as an alternative for steel reinforcement is widely investigated, to promote the use of sustainable concrete structures. This study aims to investigate the effect on durability, flexural, compressive, tensile properties, and workability of concrete by incorporating coir fibre at varying fibre content to find the fibre content which gives optimum results. The fibre contents used were 0%, 0.5%, 1.0%, 1.5% and 2.0% by weight of cement. Furthermore, the effect of modifying the surface of the coir fibres by alkali treatment (i.e. 5 wt.% NaOH solution) and coating the fibres with epoxy paint and polyurethane varnish on coir fibre reinforced concrete (CFRC) were also investigated. Tests conducted on the CFRC specimens included slump test and flexural, compressive and tensile strength tests. Water absorption and sorptivity tests were also conducted to investigate the durability. Slump (workability) and unit weight reduced with an increase in fibre content. The surface modification methods used, had resulted in an increased workability and a reduced unit-weight. A coconut fibre content of 1% produced the best combination of flexural, tensile and compressive properties. Water absorption and sorption rate per unit time, increased with an increase of coir fibre content. It is also found that epoxy paint and alkali treatment of the fibres has a positive effect on the mechanical strength properties and also the durability and workability of the CFRC specimens. However, polyurethane varnish coating had a detrimental effect on the mechanical strength properties of the CFRC specimens.
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    PublicationOpen Access
    EFFECT OF PORCELAIN WASTE AS A FINE AGGREGATE ON THE MECHANICAL PROPERTIES OF CONCRETE
    (University of Peradeniya, 2019-08-13) Kobbekaduwa, K. W. D; Perera, S. V. T
    The demand for concrete keeps significantly increasing worldwide throughout the past few years period. The exponential development rate and construction processes on developing infrastructure facilities all over the globe has resulted this situation. As an outcome of that, the excessive production of concrete has led to several environmental impacts all around the world. This study investigated the suitability of crushed porcelain waste as a replacement for fine aggregates by analysing the strength gains and other mechanical properties depending on the replaced proportions. Porcelain Waste Fine Aggregate (PWFA) which is a low water absorbing material was used in replacing conventional fine aggregates in the proportions of 25%, 50%, 75%, 85% and 100% for the concrete of Grade 30. It was found that the most suitable and economical replacement proportion of PWFA is the 75% mix as it comprised a 28-day compressive strength of 54.31 MPa which is 50% greater than the compressive strength of control mixture. Due to the higher strength, the 75% PWFA Grade 30 mix can be implemented as Grade 45 concrete which can save up to 10% of the cost. The partial replacement of sand using PWFA significantly improved the performance of concrete while addressing several environmental and economic issues related to concrete industry.