Requirements of unbound aggregate mixtures according to European specifications

2 Requirements of unbound aggregate mixtures according to European specifications 

The requirements set by CEN EN 13285 (2010) for unbound mixtures to be used in bases and sub-bases for the construction or maintenance of pavements refer to (a) mixture requirements, (b) grading requirements, (c) aggregate requirements and (d) other requirements. 

The mixture requirements consist of selecting and determining (a) the designation of the mixture, (b) the maximum or minimum (when required) fine content (passing through a 0.063 mm sieve) and (c) the percentage of oversize particles. All the above prescribe broadly the aggregate mixture. 

The mixture designation is selected out of 15 mixtures, each one denoted by the ratio 0/D , where D is the nominal upper sieve size (in millimetres). Hence, a mixture designation of 0/31.5 means that the upper (D) sieve size or the nominal maximum size of aggregate is 31.5 mm and the mixture contains all fines. 

The supplier-declared grading range is also determined by the specification having selected the general category of the aggregate mixture. 

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