The following safety measures are taken during civil engineering construction. (i) Suitable scaffolds should be provided for workmen. (ii) When ladder are used, it should be provided with foot holds and hand holds and inclination of one is to four (1 horizontal : 4 vertical) be provided. (iii) The scaffolding should be properly supported and shall have a guard rail property attached to it. (iv) Every opening in floor of a building should be provided with suitable means to prevent the fall of persons or materials. (v) Fencing and lights shall be provided to protect the public from accident. (vi) The excavated material shall not be placed within 1.5m of the edge of the trench or half the depth whichever is more to avoid collapse of sides due to surcharge. (vii) No undermining or undercutting shall be allowed. (viii) All roads and open areas adjacent to any side where demolition is to be carried out, must be closed or suitably protected. (ix) No electrical cable etc. shall remain electric...
Fibre reinforced concrete is a composite material essentially consisting of conventional concrete or mortar reinforced by random dispersal of short, discontinuous and discrete fine fibres of 25-50mm long and 0.25 to 0.50 mm in diameter, consisting of 4 to 5% weight and of specific geometry. The fibres interlock and entangle around aggregate particles and considerably reduce the normal workability while mix becomes more cohesive and less prone to segregation. The fibres suitable for reinforcing the concrete have been produced froom steel, glass and organic polymers. Naturally occuring asbestos and vegetable fibres, such as jute are also used for reinforcement. Steel, carbon and glass have higher elastic moduli than cement mortar matrix and polypropylene and vegetable fibres are low modulus fibres. High modulus fibres improve both flexural and impact resistance simultaneously whereas low modulus fibre improve impact resistance of concrete but do not contribute much to flexural strength.
Steel Fibre Reinforced concrete has extra strength in flexural, tension, fatigue, impact, greater impact to sound and spalling. These properties lead to smaller concrete sections, improved surface quality and reduced maintenance. For aggregate of 40mm maximum practicle size, the cement content shall be at least 350kg/cum of concrete.
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