Upper Concrete
If you are using a combination of two or more lower the flag, they are placed with an overlap on one another for at least 3 cm Upper panel should overlap the lower 10-15 cm docking installable with the band already hardened concrete upper cloth is placed on it, with an overlap of at least 20 cm from the joint. Evacuation is carried out at the dilution of 0.07-0.08 MPa. The duration of vacuum set at the rate of 1-1.5 min to 1 cm thick concrete layer. With less dilution of the specification, but not less than 0.06 MPa, the duration of evacuation increases in inverse proportion to the fall depression. Stop in the absence of vacuum movement of water through the transparent section of the pipeline and achieving concrete mixture density at which the surface is weak footprint of man. At the end of the process of evacuating the upper edge of the cloth roll so that the bottom could be seen filtering cloth, and then disconnect the vacuum unit and suction mat is removed.
Evacuating the concrete, you can immediately make reparation for the surface, which carried out in two stages. Primary processing is carried out smoothing machines SB-170, equipped with a disk. Secondary treatment produced 3-5 h after the primary the same machine, equipped with blades (disc removed). At Smoothing the surface move on already hardened concrete. If the area is laid concrete can not do that, then smoothing produce "back" while moving around the otvakuumirovannomu concrete. Concrete coatings must harden in wet conditions. To do this, they go to sleep with wet sawdust or cover with wet burlap or woven mats. A layer of wood shavings, mats or burlap kept wet for 7-10 days from the beginning their installation. The intensity of the wet set depending on local conditions of humidity and air temperature, but in all cases, even partial drying of the coating during this period are not allowed. Watering concrete water surfaces not covered with sawdust, mats, burlap, is not effective, as water flows down and accumulates in low areas, creating not equivalent conditions of concrete hardening, which leads to the formation of cracks in the coating