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The disposal of solid waste in open environment is a serious alarming concern that needs immediate attention from the researchers. The hazardous solid agro-industrial wastes which include: wheat straw ash, rice husk ash, corn cob ash and sugarcane bagasse ash (SCBA), having pozzolanic properties, have a versatile use in concrete. The solid pozzolana enhances the various concrete properties by the reaction of silicates with calcium hydroxide in the presence of water, which in result generate a saturated zone of calcium silicate hydrate (CSH) gel. This C-S-H gel reduces the amount of calcium hydroxide C(OH)2 during the hydration process of cement. Very limited research works have been done on concrete by partially replacing cement with SCBA. This research work was focused on evaluating the properties of concrete by partially replacing cement with SCBA at 0, 5, 10, and 15 percentages. Compressive strength, Strength activity index, and water absorption of all mixes were examined. And it was observed that all SCBA mixes showed an increase in compressive strength and at 10% replacement the strength activity index was at a peak of 115.67%, but all the SCBA mixes showed a strength activity index greater than 75% which satisfied the standard specification. The water absorption test for all SCBA mixes showed a slight increase in water absorption.

Concrete possesses distinct features that make it widely acceptable for use across the globe; however, along with its obvious benefits, it has numerous drawbacks i.e., it is brittle in nature and its production causes an adverse impact on the environment. To counter such problems, researchers around the world have introduced sustainable measures. Fibre addition is foremost among these solutions in that it prevents crack propagation and increases the overall strength of concrete. In the present age, civil engineering structures have their own structural and durability requirements and so, modification in traditional concrete has become a necessity. This research is targeted at steel fibre reinforced concrete (SFRC), which is a superior quality concrete because of its enhanced strength. The steel fibres are obtained from binding wire that is used to tie the steel reinforcement. By referring to past research, steel fibres with an aspect ratio (length to diameter ratio) of 30 were considered favourable. The controlled, mixed design of the concrete was prepared with a targeted strength of 4000 psi and, while mixing the concrete ingredients, fibres were added to allow uniform dispersion. The fresh and hardened properties of workability, compressive, and tensile strength were tested and the results of fibres at 0%, 1%, 2% and 3% concrete mass were compared and analysed. The results indicated that highest compressive and tensile strength values were achieved with 3% fibre addition. However, with further addition, it was observed that concrete loses its workability. Therefore, it is suggested that 1% addition of steel fibres produces good strength with sufficient workability.

No abstract

Silica fume is an industrial by-product that can be used as a partial replacement of cement to enhance the strength related properties of roller compacting concrete. In past, industrial wastes were used to dump on earth, river, and sea that creates a hazardous environment for aquatic life as well as for humans. Nowadays, the use of industrial by-products as cement replacement is popular in the construction industry because it protects the environment from hazards. In this research, the effect of silica fume as partial replacement of sulphate resisting cement is investigated on the compressive strength of roller compacting concrete. Total four types of mix proportions were casted using concert mix ratio as 1:2:4 to investigate the compressive strength of roller compacting concrete at 7 and 28 days of curing age. The sulphate resisting cement was partially replaced with silica fume by 0%, 5%, 10%, and 15% by weight of cement. The zero slump was maintained in all mixes. It was observed that the mix proportions containing 5% and 15% silica fume replacement showed maximum and minimum compressive strength of roller compacting concrete respectively.