Patent ID: 11008255

Abstract:
A method for preparation of 1 m3 of fresh concrete includes mixing 1000 to 2000 kg of aggregate in a forced circulation mixer, wherein 40% to 100% by weight of the aggregate is recyclate made from inert construction and demolition waste. Microsilica is added to the mixture under constant mixing, and the mixture is then mixed for 40 to 80 seconds, whereby the microsilica covers particles of the recyclate and fills up pores in the recyclate. Then under constant mixing, cement or cement and at least one substituent of cement is added to the mixture in a total amount of 135 to 600 kg, and the mixture is further mixed while sprinkling or spraying the mixture with 135 to 250 kg of mixing water for under constant mixing such that a surface of the cement is gradually wetted and a cementing compound being formed gradually adheres to the particles of the recyclate already coated with the microsilica. The mixture is continued to be mixed for 80 to 160 seconds, wherein fresh concrete is prepared.