We are concerned about transporting concrete over the welded wire mesh and polyethylene vapor barrier on large pours where the truck-mixer chute won't reach. How can this be done without puncturing the vapor barrier?
An old Concrete Information sheet of the Portland Cement Association, called "Concrete Floors on Ground for Residential Construction" (CP 25-6) describes one method of protecting the vapor barrier against workmen walking on it. After the granular fill has been compacted and leveled, a grout coat is broomed or floated over it to a thickness of 1/2 inch or more to produce a smooth surface. The grout is made of 1 part portland cement and 3 parts sand. After this has hardened and dried, a continuous membrane dampproofing layer is put over it and up the sides of the wall to 1 inch above finished floor level. This membrane consists of two layers of 15-pound roofing felt with layers of hot asphalt mopped below, between and above. The smooth, hard surface below the vapor barrier diminishes its susceptibility to puncturing.