压碎的聚集体

Sands, gravels and crushed stone come in a variety of shapes and sizes and classification of these materials into approximate size fractions is called grading. Traditional terminology was to classify aggregates as belonging to one of three categories; all in aggregate; coarse aggregate and sand. These are defined below but it should be noted that the first two categories are not used in mortar production.

·            All in aggregate: this is material composed of a mixture of coarse material and sand.

·            Coarse aggregate: over 4mm material. This classification can be further divided into graded and single-size aggregates.

·            A graded aggregate consists of particles of different sizes from the maximum down to the minimum.

·            Sand: The European Standard uses the term fine aggregate in place of sand for material less than or equal to 4mm in size but the terms are interchangeable and the word ‘sand’ more commonly used.