Concrete

The PH value is very important in construction activities, particularly for reinforced cement concrete as it is a composite material created with embedded steel bars. If the PH value of water is less than 7 which is the neutral value for good drinking water, then the water will be acidic. The cement concrete’s PH value for fresh concrete will be 12 to 13. This indicates that the concrete is alkaline which gives passivity to protect steel bars from getting corroded. If the water having less PH value than 6, it will start neutralizing the PH value of concrete from 12, to 7 and less, the long lasting alkaline passivity of concrete is considerably reduced, triggering the corrosion chmesity for steel and destroy the steel over a period.

IS 10262: 2009 and IS: 10262: 2019 in concrete mix design:

This IS provides guidelines for proportioning concrete mixes as per requirements using the concrete materials and the supplementary materials. IS 10262: 2019 is the second revision of the first edition IS 10262: 2009 in concrete mix design in which the following major changes have been made(As per the description of the code):

• The standard was divided into five sections as General, Ordinary and standard grades of concrete, high strength grades of concrete, Self-compacting concrete and Mass concrete.
• A new section for Mix proportioning procedure for High strength concrete for M65 and above(up to target strength of M 100) was included.
• The formula for the target mean strength for mix proportioning for refined by including a new factor based on the grade of the concrete. It was done to ensure a min margin been the characteristic compressive strength and the target mean strength.
• A graph of W/C vs. 28 days strength of concrete introduced for different grades and types of cements for an alternative to initial water-cement ratio assumption.
• In the design of normal concrete mix proportion, the consideration of air content was reintroduced.