Page 66 - Lecture Notes DCC3113

(c) Aggregate
The aggregate shall be selected crushed materials meeting the gradation requirements given in Table
4.2.5. The material shall be free of roots, sod and weeds. The crushed aggregate shall consist of hard,
durable particles of accepted quality, free from an excess of flat, elongated, soft or disintegrated pieces or
objectionable matter. The method used in producing the aggregate shall be such that the finished
product shall be as consistent as practicable. All stones and rocks of inferior quality shall be removed.

The gradation in Table 4.2.6 represents the limits which shall determine suitability of aggregate for use
from the sources of supply.

Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 21)

Preparation of materials used in the Road Surface

Materials

(a) Aggregates

Aggregates for asphaltic concrete shall be a mixture of coarse and fine aggregates, and mineral filler. The
individual aggregate shall be of sizes suitable for blending to produce the required gradation of the
combined aggregate, all to the satisfaction of the S.O.

Coarse Aggregate

Coarse aggregate shall be screened crushed hard rock, angular in shape and free from dust, clay,
vegetative and other organic matter, and other deleterious substances.

They shall conform to the following physical and mechanical quality requirements;
ii. The Los Angeles abrasion value when tested in accordance with ASTM C 131 shall be not more
than 25%.
iii. The weighted average loss of weight in the magnesium sulfate soundness test (5 cycles) when
tested in accordance with AASHTO Test Method T 104 shall be not more than 18%.
iv. The flakiness index when tested in accordance with MS 30 shall be not more than 25%.
v. The water absorption when tested in accordance with MS 30 shall be not more than 2%.
vi. The polished stone value when tested in accordance with MS 30 shall be not less than 40 (only
applicable to aggregates for wearing course).

Fine Aggregate

Fine aggregate shall be clean screened quarry dust. Other types of fine aggregate may be used subject to
the approval of the S.O. Fine aggregate shall be non-plastic and free from clay, loam, aggregation of
material, vegetative and other organic matter, and other deleterious substances. They shall conform to
the following physical and mechanical quality requirements;

59