If tomato juice is having a pH of 4.1, the hydrogen ion concentration will be

A rectangular column section of $$250\,\,mm \times 400\,mm$$ is reinforced with five steel bars of grade $$Fe$$ $$500,$$ each of $$20$$ $$mm$$ diameters. Concrete mix is $$M30.$$ Axial load on the column section with minimum eccentricity as per $$IS: 456$$ - $$2000$$ using limit state method can be applied upto

$$IS:$$ $$1343 – 1980$$ limits the minimum characteristic strength of pre-stressed concrete for post tensioned works and pretension work as

As per Indian standard code of practice for prestressed concrete $$(IS:1343-1980)$$ the minimum grades of concrete to be used for post-tensioned and pre-tensioned structural elements are respectively