Assessment method for fresh concrete spreadability

Abstract

Abstract The results of studies of the fresh concrete spreadability using 3D printing of construction products are presented. The 3D printer is an automated device for the construction of buildings and erectioins, the manufacture of specific structures and products by the method of three-dimensional printing of fine-grained fiber-reinforced concrete with special additives, sand concrete, geopolymer concrete, etc. Assessment methods for the concrete consistency occurring during installation are considered. The applied methods for assessing the spreadability of fresh concrete take into account only its own mass of concrete and do not reflect dynamic processes. The use of the ultrasonic method allows mass testing of products of any shape repeatedly, to continuously monitor the growth or decrease in strength. The disadvantage of this method is the error in the transition from acoustic characteristics to strength. The spreadability of the concrete mixture is estimated depending on the amplitude-frequency characteristics. The dependences of the amplitude of vibrations and accelerations of the paver hopper on the density of the concrete mixture are given. Particular optimization of vibration accelerations by the amplitude of the oscillations of the hopper walls, the amplitude of the oscillations of the charge layers and the stiffness of the vibration dampers is performed.