100. Mixing and pouring of concrete.- The employer shall ensure at a construction site of a building or other construction work that- (a) the concrete mixture does not contain any material which may unduly affect the setting of such concrete, weaken such concrete or corrode steel used with such concrete; (b) when dry ingredients of concrete are being mixed in confined spaces such as silos,- (i) the dust shall be exhausted at the time of such mixing; and (ii) in case the dust cannot be exhausted, as specified in sub-clause (i), the building workers shall wear respirators at the time of such mixing; (c) when concrete is being tipped from buckets, building workers are kept out of the range of any kickbacks of such buckets; (d) loads are not dumped or placed on settling concrete. | 
