Krishna Udyog offers "Rapidex" additive for manufacture of cement. Rapidex is very useful for achieving high early strength of cement and can be used as additive for manufacturing Portland slag cement, Portland pozzolana cement, ordinary Portland cement and composite cement. Rapidex is a mineral admixture of amorphous, calcined silica and alumina which reacts aggressively with calcium hydroxide to form compounds with cementatious value that are blended of inter-ground with cement. It enhances the performance of cement characteristic properties and resistance under aggressive environment. The performance enhancing properties of Rapidex are achieved through two principal mechanisms. One is physical effects. The extremely fine particles of Rapdex are able to fill the microscopic voids between cement particles, improving packing and creating a less permeable concrete structure. The second is in the curing process, the silica reacts with the free calcium hydroxide produced t form additional calcium silicate hydrate (CSH), and enhance cement to aggregate bond. The filler effect plays a major role in controlling bond by modifying the properties of fresh concrete to reduce internal bleeding, voids and transition zone. The Rheological properties off concrete play a major role in developing high early strength. The advantages of Rapidex include increases high early strength in 1, 3 and 7 days and continuous gain of strength till 28 days, reduces clinker consumption by 5 to 10 percent (depends on the quality of clinker), water impermeability, enhance surface definition, bleeding prevention, resists from chemical attack and prevent from alkali silica reaction in concrete, no effect on LOI and IR, free from chloride, alkali and sulphate, reduces shrinkage in concrete, work as air entraining agent.Krishna UdyogKolkata, West BengalMob: 0987401833, Fax:033 0342-255 9855 Email: guptaarya233@gmail.com krishna_udyogbdn@yahoo.com