311) For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be

312) Maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is

313) In case of hand mixing of concrete, the extra cement to be added is

314) For walls, columns and vertical faces of all structural members, the form work is generally removed after

315) The individual variation between test strength of sample should not be more than