Civil Engineering - Building Materials - Discussion

What is all type of cement final and initial setting time?

Lime pozzolana mixture has three types.

LP40 initial setting time is 2 hrs (120 mins) and final setting time is 24 hrs (M4 Grade).

LP20 initial setting time is 2 hrs (120 mins) and final setting time is 36 hrs (M2 Grade).

LP7 initial setting time is 2 hrs (120 mins) and final setting time is 48 hrs (M07 Grade).

This mixture used for masonry mortar, foundation concrete, leveling coarse under floors, road and airfield bases, precast building blocks.

Refer for more details IS:4098-1967.

What is the difference between the grade 40, 53, 33, etc?

Ordinary Portland Cement (OPC) is graded according to their strength. The grade indicates the compression strength (mpa) of the concrete that will attain after 28 days of setting.

OPC initial time 30 minutes.

Initial time 30 minutes opc.

Initial setting time should be less than 70 mins.

Why it's initial setting time more than to opc?

The calcium hydroxide reacts with the carbon dioxide in the atmosphere to give calcium carbonate that gains cementing properties (Carbonation) as their is low CO2 in air thats why it takes Longer time to Set than OPC which uses water for Setting ! And probably that is why Lime Cement is not used in Under water Structures due to Absence of C02.

I am not getting it, Give me the explanation.