THE EFFECT OF DIFFERENT AGGREGATE TYPES AND GRADATION ON THE CHARACTERISTICS OF BITUMINOUS MIXTURES

Mineral aggregate constitutes approximately 95% of hot-mix asphalt by
weight. Thus it contributes a lot on the characteristic of bituminous mixtures. This
study is to determine the effect of different aggregate types and gradation on the
characteristics of bituminous mixtures. Granite and limestone are tested for aggregate
suitability as highway construction material and each of them were employed to
produce two aggregate gradations, which are well-graded and gap-graded. Lab tests
were done to determine the characteristics of the bituminous mixtures of each
combination. The results were compared with the specifications of the Jabatan Keija
Raya (JKR). From the result obtained, both granite and limestone are usable as
highway construction material. However, granite is more recommended for highway
purpose as it has higher strength and more durable compared to limestone. A well
graded mixture is proved to be able to carry and spread load imposed on it better than
a gap-graded mixture.