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Basecourse/Topcourse is primarily used as a foundation material for roads and buildings.  These products are “All Passing” (AP) meaning all material smaller than a particular size is included in the product.

The Number at the ends refers to the screen size (the largest size of rock in the product). A common size is 40mm

Letters are added before the AP to give more information on the product.

Common products are:

CAP - Crushed All Passing

GAP – General All Passing, another name for CAP, generally from hard rock quarries where everything is 100% crushed anyway, so specifying ‘crushed’ is not needed.

M4 AP – NZTA road specification. NB: Is a CAP that passes the requirements for NZTA to be used on state highways.

SAP – Stabilised All Passing. Stabilised meaning clay or lime has been added.

CTB – Cement Treated Basecourse, generally meaning that a base course has been processed through a pugmill and cement added to it.

Example: CAP 40

Crushed All Passing 40mm. Meaning the rock is crushed and graded and consists of particles from 40mm to 0mm.

Chip is Primary used for sealing roads, asphalt, and drainage materials. Again the naming convention uses abbreviation followed by a number specifying the size.

“Chip” (C) means that the rock has been crushed and has a high broken face content.

Chip can either be a single sized product, with the number in the name referring to this. Ie. ‘SC10” means, it is a ‘screened chip’ that is all around 10mm in size. Chip can also be graded, meaning that it has been screened to include all everything from the top size, to the bottom size. Ie. GC14-10 is a ‘graded chip’ that contains chip from 14mm down to 10mm.  

Chips are commonly referred to by their old name convention; the ‘grades’. Ie an SC10 product can also be called a Grade 5 chip. This is because it would require 5 individual chips, stacked on top of each other to reach 1 inch in height. Therefore, the larger the chip, the smaller the ‘grade’. Ie it only requires 2 Grade 2 chips stacked to reach 1 inch in height.

Common chip products:

SC- Screened Chip (used for chip sealing roads, and asphalt)

GC – Graded Chip (used in primarily for drainage material)

Aggregate is the stone (larger than sand) that commonly is used to produce concrete. This can either be called ‘rounds’ as in alluvial quarries this is uncrushed, washed round stone. But in hard rock quarries, where the aggregate is crushed, it is simply ‘concrete aggregate’.

Aggregate normally is graded over a range of sizes, ie. 20mm to 14mm as one product, then 14mm to 8mm as another product.

Common products are:

GR40-20 – Graded Rounds from 40mm to 20mm

CA14-8 – Concrete Aggregate from 14mm to 8mm

Sand is primarily used for concrete and asphalt. There is natural sand, that has had little processing done, and manufactured sand, known as ‘dust’. The naming convention of sands uses the same abbreviation/numbering combination.

Common products are:

AP5 – Commonly known as ‘dust’ or ‘crusher dust’ as this material is manufactured in a crusher. Name signals that it is ‘All Passing’ 5mm

WAP 5 – Commonly called ‘Washed Dust’ . This is AP5 that has had the fine bottom size washed out. Means ‘Washed All Passing’ 5mm.

NAP5 – Commonly called concrete sand. NAP5 means that it is ‘natural, all passing’ 5mm. Ie, this material has not been crushed and has just been washed out of raw feed material.

NAP3 – Commonly called plastering sand. NAP3 means that it is ‘natural, all passing’ 3mm

Top course
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