Optimising the amount of aggregate fractions

Nonlinear models help reduce cementconsumption by better packing of aggregates

Cement consumption in concrete can be reduced by simply mixing the right amounts of aggregates of different sizes, which result in minimum
voidage. With three or more sizes of aggregates, determining their right amounts is not a trivial problem. The optimisation problem can
be solved quickly after a mathematical model describing the voidage in terms of the fractions of the different sizes becomes available. When
each aggregate fraction is not of a constant diameter, and the shape of the particles is not spherical, there are no simple solutions. This article
describes how it is feasible to determine the optimal amounts of aggregates of three sizes using nonlinear modelling on data from a short
series of well planned experiments. This approach does not require the assumptions of spherical particles or constant diameters with no
variation in each size. This procedure can help save typically several percent of cement. Its environmental impact is also significant in terms
of reduced carbon dioxide emissions.