Abstract
Abstract This paper discusses ways of recycling woodworking waste into light aggregate, optimal compositions of modified binders, as well as the mechanism of cement hydration in the presence of dispersion polymer powders. The methods of obtaining light aggregate based on woodworking waste by granulating in a disc granulator, which is a plate with a tilt angle of 450 and a number of turnovers of 17-19 rpm, are considered. Methods for obtaining granulated aggregate using sawdust of various fractions by the roasting free method are presented, optimal granulation modes are determined, and the main characteristics of the resulting aggregate and concrete based on them are studied. The optimal composition of granulated aggregate on modified cement provides 40 … 60 % of wood processing waste, 60 … 40 % of cement, 25 … 32 % of water and granulation time - 7 … 9 minutes. With this composition, the bulk density of the resulting aggregate corresponds to 850…750 kg/m3, the maximum strength of the granules when compressed in the cylinder is 3.5…4.1 MPa. The optimal content of the polymer additive in the binder is in the range of: mowilith - 0.4…0.7 % and tylose - 0.21…0.13 %. Granulated aggregate on modified aggregate has a frost resistance in the range of F35… F50. The choice of granulated aggregate on modified cement showed the effectiveness of the aggregate for light concretes. The strength characteristics of modified concrete of 25-75 brands were studied. The mechanical properties of modified concrete depending on the average density were studied. Concrete with an average density of 1000 kg/m3 has M25 brand, at 1200 kg/m3 - M35, at 1300 kg/m3 - M50, at 1500 kg/m3 - M75.