Special Concrete Technologies

Roller Compacted Concrete

Roller Compacted Concrete (RCC) is defined as concrete compacted by pneumatic Roller, it is usually mixed using high-capacity continuous mixing or batching equipment, delivered by trucks or conveyors, and spread with one or more bulldozers in layers (also called lifts) and compacted by vibratory roller. RCC is used mainly for dam, mass pavement concrete

The nominal maximum aggregate size can range up to 150 mm. Cement content is usually lower than that used in a conventional concrete mix, but similar to that of mass concrete to prevent effects of heat of hydration and shrinkage which may result to cracking of the concrete in massive structures. Usually high amount of Pozzolan is incorporated into the mixture up to 70% by weight of the total cementitious content. An effective retarding admixture like Plastiment TM 25 is highly recommended for reducing water cement ratio and long retardation effect on the fresh RCC mixture. The Plastiment TM 25 delays setting time to have proper placement and compaction of new layer over the retarded previous RCC layer without cold joint and risk of producing micro cracks. It increases cement efficiency, increasing bonding of mortar paste, reduces water content and consequently increasing mechanical strengths.