Gator Aqua Rock ASTM No. 9 Aggregate: Permeable Paver Guide

Gator Aqua Rock is not a polymeric sand, and it is not meant to harden. Alliance describes it as fractured, high strength granite calibrated to the ASTM No. 9 gradation, which is the jointing and bedding aggregate that permeable interlocking paver systems are designed around. In a permeable system the joint has one job, letting water through, and Aqua Rock is built to keep that path open where ordinary sand would blind it off within a season.

This guide covers what Aqua Rock is, the ASTM No. 9 sieve figures, where Alliance rates it for use, the bedding and compaction requirements, coverage per 50 lb bag and by super sack, and the questions we hear most, using figures from the Alliance Gator Aqua Rock product page and technical data sheet. Anything the product page does not state, we leave to the data sheet in our TDS and SDS library.

What Gator Aqua Rock is

Alliance Gator Aqua Rock is a chip stone, not a sand. Alliance states that permeable pavers only work if the joints stay open, that ASTM No. 9 chip stone is the specified material for those joints, and that Aqua Rock is its calibrated version of that stone. Here is how it differs from the polymeric sand most paver owners know:

Feature	Typical polymeric sand	Gator Aqua Rock
Purpose in the joint	Designed to seal the joint	Designed to let water move through the joint
Material	Calibrated sand with a polymer binder	Fractured high strength granite, ASTM No. 9 gradation
Fines	Includes fine particles by design	0 to 5 percent passing the No. 50 sieve, so the voids stay open
Shape	Not applicable	Angular, interlocks and resists rutting; rounded pea gravel rolls
Also used as bedding	No	Yes, the same material works as bedding and joint fill
Packaging	Usually 50 lb bags	50 lb bags or a 2,200 lb super sack

Alliance also notes that Aqua Rock reduces stormwater runoff and helps prevent erosion, and that it is calibrated for the majority of permeable pavers. If your project is a traditional, non permeable paver installation that needs sealed joints, you want a polymeric sand instead; see polymeric sand vs resin sand for how the jointing families differ.

Gator Aqua Rock specifications

Specification	Per the Alliance product page and data sheet
Bag weight	50 lb (22.7 kg), 56 bags per pallet
Bulk option	2,200 lb super sack, 1 per pallet
Color	Granite grey
Gradation, ASTM No. 9	3/8 in sieve 100; No. 4 85 to 100; No. 8 10 to 40; No. 16 0 to 10; No. 50 0 to 5
Coverage, 50 lb bag	20 to 25 sq ft on a 2-3/8 in paver
Coverage, super sack	880 to 1,100 sq ft
Bedding course	50 mm, screeded to plus or minus 10 mm over a 3 m straight edge
Minimum subgrade slope	0.5 percent
Minimum finished surface slope	1 percent
Compaction	Low amplitude 75 to 90 Hz plate, minimum 4,000 lb centrifugal force, at least two passes
Traffic rating	Residential and commercial, including driveways and parking lots

The gradation numbers are the percentage of material passing each sieve. The practical takeaway is the last row: almost nothing in the bag is fine enough to pass a No. 50 sieve, which is why Alliance says the voids stay open instead of silting shut.

Where to use it (and where not to)

Alliance rates Gator Aqua Rock for:

• Permeable paver joints
• The bedding course under permeable pavers
• Driveways, parking lots, patios and walkways
• Concrete pavers and wet cast products
• Foundation material under Gator Base, with no compaction needed

The Gator Base use is worth a closer look. Alliance says Aqua Rock doubles as bedding under Gator Base panels and needs no compaction there, unlike a sand bed, which makes it the easier option for that system. If you are weighing panels against a gravel base, our Gator Base vs gravel guide walks through the trade offs.

Alliance also lists conditions that must be met, straight from the manufacturer:

• No mud or sediment on the base or bedding. Contaminated material must be removed and replaced, not just raked over. Fines are what blind a permeable joint, so this is not a cosmetic rule.
• No traffic on screeded bedding. Do not walk or drive on the bedding before paving starts.
• Minimum slopes. 0.5 percent on the subgrade and 1 percent on the finished surface.
• Cut sizes and drainpipes. Cut pavers no smaller than one third of a whole unit, and take care not to damage drainpipes during compaction.

Because the product page does not list a joint width range, we do not state one here. If your paver has an unusual joint spacing, check the manufacturer data sheet in our TDS and SDS library, or call us before you order. Alliance's own note on the product page applies: if the answer is that this is not the right product for your job, we will say so.

How to install Gator Aqua Rock

Alliance says the full step by step procedure is in its official documentation. The product page gives the shape of the job in this order:

1. Spread the bedding. Place Aqua Rock over the base course at 50 mm thickness.
2. Screed it. Screed to plus or minus 10 mm over a 3 m straight edge, and keep all traffic off it until paving starts.
3. Lay the pavers. Keep edge cuts no smaller than one third of a unit. On vehicular work, lay the pattern at 45 degrees to the direction of traffic.
4. Sweep the joints. Sweep Aqua Rock into the joints and sweep the paver faces clean of excess.
5. Compact. Use a low amplitude 75 to 90 Hz plate compactor of at least 4,000 lb centrifugal force, and make a minimum of two passes.
6. Check joint height. Confirm the joints are filled to 3 mm from the paver top, then top up or remove material as needed.

There is no water activation and no cure time in the manufacturer's sequence, because nothing in the joint is meant to bind. That also means there is no dry surface or temperature requirement on the product page, so we do not state one.

How much Gator Aqua Rock you need

Alliance gives coverage on a standard 2-3/8 in paver and notes that it varies with paver shape and joint width:

Package	Coverage per the product page
50 lb bag	20 to 25 sq ft on a 2-3/8 in paver
2,200 lb super sack	880 to 1,100 sq ft

Those figures cover the joint fill. If you are also using Aqua Rock as the 50 mm bedding course, you will need more material for the bed, and the product page does not give a bedding coverage figure, so size that layer from the data sheet. Start with our polymeric sand calculator for the joint estimate, then compare it against the 20 to 25 sq ft per bag figure above. Larger jobs are usually handled by the super sack; call (856) 418-4895 and we will help you settle on the right quantity.

Warranty and testing

The Alliance product page describes Aqua Rock as high strength fractured granite graded to meet ASTM No. 9 and rated for residential and commercial traffic. It does not list a warranty term or lab test results for this product, so we do not state any here. The Gator Aqua Rock technical data sheet with the full sieve analysis, coverage, bedding tolerances and installation procedure is published by Alliance and listed in our TDS and SDS library.

Watch the manufacturer's video

Frequently asked questions

What is ASTM No. 9 stone?

A specified aggregate gradation, roughly 3/8 in down, with almost no fines. Alliance states it is the gradation permeable interlocking paver systems are designed around, and Aqua Rock is graded to meet it.

Can I use Gator Aqua Rock on a driveway?

Yes. Alliance rates it for residential and commercial traffic, including driveways and parking lots. On vehicular work, lay the pavers at 45 degrees to traffic and follow the compaction spec of a 75 to 90 Hz, 4,000 lb plate with at least two passes.

Why not just use polymeric sand in a permeable paver?

Polymeric sand is designed to seal the joint. In a permeable system you want the opposite, water moving through it. Alliance says sand fines migrate down, fill the voids and stop the surface draining within a season or two, while ASTM No. 9 chip stone has 0 to 5 percent passing the No. 50 sieve so the voids stay open.

Can I use Aqua Rock under Gator Base?

Yes. Alliance lists it as foundation material under Gator Base with no compaction needed, which it calls the easier option compared with a sand bed.

Is there a permeable jointing product that does bind?

Within the Alliance line, Gator Nitro Joint Sand is the permeable jointing sand for drainage bases, and Alliance lists it as a product that pairs with Aqua Rock. Our Gator Nitro guide covers how that air cure product works.