About defining pouring parameters massive flat foundation slabs
Abstract
About defining pouring parameters massive flat foundation slabs
Incoming article date: 16.06.2023An approach is proposed to determine the parameters of concreting flat massive foundation slabs - the operational performance of the concrete mix supplier, vehicles and concrete pump, taking into account the limiting factors - the intensity of the supply and placement of the concrete mix and the time of overlapping layers. A scheme for determining the overall coefficient of operational performance is proposed. As a result of timing, the values of the transition coefficient from technical to operational productivity, respectively, for a concrete mixer truck with a volume of 10 m3 from 0.54 to 0.65 and 0.41 for a concrete pump truck with a technical productivity of 120 m3 / h, respectively, were determined when concreting a massive flat foundation slab with a volume of 1500 m3 using concrete mix with grade P4 for workability at a delivery distance of up to 50 m. It is proposed to consider a coefficient that takes into account the decrease in the productivity of an autoconcrete pump due to the variability of the concrete mix supply mode as the main reserve for increasing operational productivity. Schemes are given for determining the duration of concreting a structure without technological interruptions, both with an equal thickness of the stacked layers, and with different schemes for assigning the thicknesses of the stacked layers. The inexpediency of erecting such structures with a layer overlapping time of less than 4 hours is shown. The approach considered in the work can be used to select rational methods for concreting such structures in a continuous pattern or with division into temperature-shrinkage blocks and the construction of working joints. The latter scheme, in connection with the problem of ensuring the quality of the seams and the solidity of the structure, seems to be less preferable.
Keywords: concreting intensity, technical productivity, operational productivity, massive flat foundation slabs, layer overlap time, layer thickness