Application of crushed concrete waste to recycled aggregate for concrete

Concrete waste is hardly recycled to be used. as aggregate for concrete by primary crushing. The reason is that micro auks remain in crushed concrete and particles of only mortar and/or cement Paste are included. Therefore many techniques have been proposed and practiced to take out only hard aggregate from concrete waste However, these techniques have required significantly much energy and produced considerable much carbon dioxide into the atmosphere. This paper describes the effects of processes for recycled aggregate, produced with the primary crushing to absorb water or pozzolanic liquid on the properties of concrete. The absorbed water or pozzolanic liquid is considered to fill the micro cracks in recycled aggregate with cement gel by cement hydration or pozzolanic reaction. With this technique, the strength of recycled aggregate concrete is high enough to construct ordinary concrete structures, even though the only crushed particles of concrete wastes were used.