As nation is going towards the competent level worldwide, a new product named as "Capping Gypsum" has been invented by the company for construction field, which works more efficiently and effectively than method like grinding and then capping by only neat cement and water without wasting time to tend to bleed, shrink and make unacceptable caps.
Do you follow the correct way to measure the strength? There are a lot of factors like surface flatness and horizontal, which influence the Compressive strength value.
IS 516 Indian Standard: According to (1) IS 516 Indian Standard, the ends of all cylindrical test specimens that are not plane within 0.05 mm shall be capped. There are two ways to meet this requirement. One is using capping material and the others is grinding.
1. Grinding Method: Grinding machine is a very common standard surface treatment method. But the user needs to invest the machine with huge capital and do the periodic maintenance otherwise the surface will get uneven.
2. Capping material: There are four capping materials, which are qualified in the IS 516 standard and ASTM C617 standard and it is comparable in table 1 :
|Capping Method||Material||Operation Temp.||Hardening Time||Operation Range|
|Neat Cement Capping||Cement + Water||Room Temp.||120 to 240 mins||0 to 3000 psi|
|Sulphur Capping||Pure Sulphur||~ 140 °C||120 mins||0 to 3000 psi|
|Neoprene Pad Capping||Neoprene pad||Room Temp.||NA||0 to 9000 psi|
|Hard Plaster Capping||Gypsum (We use)||Room Temp.||30 mins||0 to 9000 psi|
Comparison of Capping Gypsum and Grinding method Surface Flatness, diagram
Pressure Uniformity - pressure distribution
At present, due to the unique technology, They are the exclusive capping material supplier and have 100% market share worldwide. Sulfur capping is prohibited for safety reason and rubber is banned by the market for the unstable performance, since the international business started in 2013. High strength gypsum is absolutely the revolutionary capping material in the next environmental highly concerning generation.