Community Research and Development Information Service - CORDIS

Manufacturing technique increasing cement strength, reducing cost

Conventional OPC (Ordinary Portland Cement) takes about two to three hours to set. However, a German company is developing a new manufacturing process called HEM (High Energy Milling), whereby the concrete setting times are just two to three minutes!
Manufacturing technique increasing cement strength, reducing cost
The current OPC manufacturing techniques are low kinetic with a drum mill processes, and have a PSD (Particle Size Distribution) where 90 percent of total particles are 50 mm. The proposed system however, is a fast process route for particle size reduction of OPC where it has been mechanically refined to just 2 and 9 mm respectively.

When particle sizes in any compound such as cement or other material is reduced, the interstitial sites (spaces between particles) are also reduced. Hence it is the interstitial sites that make a compound weaker or stronger; with OPC particle size reduction the cement becomes denser, which in turn increases the potential compressive strength.

OPC is produced all over the world and generally has compressive strength of 40 Mega-pascals after 28 days of curing. To increase the compressive strength, the German company followed the ASTM C109 procedure as close as possible whereby they produced a number of cement pastes.

The results obtained demonstrate that there is a substantial increase in material compressive strength when compared to OPC. An example mixture showed strength magnitudes of 320kg/cm squared on the first day and 1100 kg/cm squared after 28 days of curing.

All this is a result of the HEM and the ability to operate this process continuously with an integrated powder classifying/separating system. The cement processing times are reduced to about one to three minutes. Other HEM developments show that the firing temperature of 1150 Celsius can also be drastically reduced, thus also slashing future manufacturing costs.
Record Number: 81504 / Last updated on: 2005-09-18
Domain: Industrial Technologies