Fly ash is a fine grey powder consisting mostly of spherical glassy particles that are produced as a by-product in coal fired power stations.

Fly ash has pozzalonic properties, meaning that it reacts with lime to form cementitious compounds. It is commonly known as a supplementary cementitious material.

Grade 1 fly ash is a premium product designed to conform with the requirements of AS3582.1 Part 1: Fly ash.