How to Install a Concrete Mat

Installation instructions for Flexible and Firm Concrete Mats

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Guide for Installation of Concrete Erosion Mats

Installation Anchoring and Handling Concrete Erosion Mats

A guide to design, usage, anchoring, overlapping and installation and handling of concrete mats

Please note that Australian Concrete Mats (ACM) technical drawings, illustrations, notes and anchoring details are to be used as a guide only. Every soil condition, water flow rate and project have varying parameters. ACM recommend the use and anchoring details be designed specifically by a qualified and certified engineer who is familiar with your site and project conditions.

 

Longitudinal Joins

When laying the mats side by side, it is best to make the longitudinal join go in the same direction as the water flow. This helps with preventing the water getting under the mats.
Where the concrete mat sections meet, install tightly side-by-side ensuring no gaps. Join together using anchoring ubars or zip ties at 900mm increments.
We also recommend placing an extra 800mm wide joining strip (two layered) under the join evenly spaced on either side.

NOVEMBER 2023 – These notes are an amendment and update to the installation guide booklet. This applies to longitudinal joins when laying mats side by side where there is an expected high water flow and/or alluvial soils or areas of erosion.

Transverse or Overlapping Joins

On the transverse or overlapping joins ensure the mat that is placed on top is in the direction of water flow. The concrete mat panels should overlap each other by 450mm under the previous panel.
It is recommended to dig and place the underside mat 450mm under the previous panel. Tie the over-lap with a UBar Anchor or metal zip ties at 900mm increments.

Trenching in Sides

If the edge of the concrete mats is exposed to sheet flow, recess the outside 2 rows of the blocks. This will reduce the water from getting under the Concrete Mats.

In high flow water areas, place the mats into a 300mm wide x 600mm deep trench and backfill. Or dig the bottom of the mat 450mm beyond the anticipated scour point

Start Of Water Channel Mat

At the start of a water channel, trench in the leading edge 450mm or 3 blocks and backfill with non-erodible soil.
Additional anchors are recommended at every 600mm spacing to prevent the water from undermining the mats.

UBar Anchoring

We recommend getting an engineer to designthe anchoring methods. UBar anchors are primarily used to help stabilise the mats in position and prevent water from getting under the mats and eroding the subsoil. They are designed to help hold the mats in place so the vegetation can grow through.
You can never have too many UBar anchors. UBar anchors are made 300mm, 450mm and 600mm long or custom lengths. In an area where the soil is alluvial other anchoring techniques can be used, like Earth Anchors. In hard surface areas use screw bolt with washers. (Refer to next section)

Australian Concrete Mats are anchored using ubar anchors every metre each side of the mat and at the joins. See how they are hammered in to start then pushed in by excavator to finish. you can never anchor enough – do not reply on weight of the mat to hold in place – especially if you expect a high flow of water across mat or on slopes or curves. Refer to our anchoring guide for best methods (click here).

Anchoring in High Flow Waterways or Alluvial Soils

We recommend getting an engineer to design the anchoring methods.

In areas with high water flow or with alluvial soils, may require additional anchoring methods
• Use UBars Anchors with longer legs
• Using Hulk Earth Anchors or a washer to hold down plate over the concrete mat.
• Using Y12 Deform Bar rods at the base of the concrete mats in-between the concrete shapes and pin over the rods to displace the loads.

Anchoring mats into Rock Shelf or Concrete Slab

We recommend getting an engineer to design the anchoring methods.

In areas with high water flow or with alluvial soils, may require additional anchoring methods

  • Use UBars Anchors with longer legs
  • Using Hulk Earth Anchors or a washer to hold down plate over the concrete mat.
  • Using Y12 Deform Bar rods at the base of the concrete mats in-between the concrete shapes and pin over the rods to displace the loads
  • Anchor the Y12 reinforcing rod down using screw in Galvanised high-strength masonry anchors (recommended size is 12 x 150mm
    or longer) placed every 800mm apart.
  • A 50×50 3mm Galvanised washer(or larger), must be used with the Screw Bolt to secure and pull the Y12 rod and concrete mat down.

Cutting The Mats

Cutting the Geogrid material is easy. We have found a battery grinder with a blade is easiest.
A pair old industrial scissors or a sharp knife can do the same job.
You do not need to cut the concrete; you only have to cut the Geogrid Material and underlay.

Hand Placement Rods

To help manually position the mat into place we recommend using our complimentary Hand Pulling Rods.
Not only do they save the bending of your back, but they also help with preventing your fingers being pinched.

Seeding and Back Filling With Top Soil

In areas that require the Concrete Mats to have grass to help anchor the mats down, we recommend seeding directly over the geofabric mats. Placing 50mm of topsoil and watering in.

The best tools to help spread the topsoil is a concreting aluminium rake.

If using mats as pavement surface like a driveway its best to top fill with road base that has a high clay content so that the mix sticks between the concrete shapes and minimises washout.

Construction Notes

An Engineer must design and /or sign off on the design and onsite installation.

Grade the sites so that water will not flow above, below, or around the outside of the area protected with Australian Concrete Mats. All subgrade surfaces prepared for placement of mats shall be smooth and free of all rocks, sticks, roots, other protrusions, or debris of any kind.

Apply site specific seed, including native grasses directly over the concrete mats and cover with top soil.
Australian Concrete Mat rolls are available in width of 1200mm or 2400mm wide.

A) To achieve wider widths, install concrete mats adjacent to one another, install additional underlay geogrid under all adjoining mats. A minimum of 450mm of underlay shall extend under each side of the mat and directly against the subgrade.

B) Install 300mm, 450mm or 600mm rebar U-anchors or stainless steel zip ties in 900mm increments the length of the longitudinal seam. (or as designed by an Engineer for the conditions).

At the beginning of the Australian Concrete Mats, transition the initial leading edge properly with matting or sod. If exposed to concentrated flows embed 450mm vertically into the subgrade to serve as an anchor trench. The trench shall be filled and compacted with suitable fill or other (as specified by Engineer).

For additional sections of mat, the mats must be overlapped. The downstream section must be underneath the upstream section by at least 450mm. Prior to installing overlap, flip upstream mat back 600mm. Excavate 60mm of soil 450mm from edge of the upstream mat. Downstream section is laid in the shallow trench, lightly spread topsoil, seed and fertilize over the initial edge. Flip end of the upstream mat over the soil covered initial leading.

Install 450mm U-Anchors in 900mm increments across the overlap, install anchors directly behind blocks. U anchors consist of 12mm rebar U-anchor with 450mm legs.

At the end of the armoured channel, embed the mat 450mm into a termination trench. Fill and compact termination trench with soil (determined by Engineer).

Technical Drawings for Installation of Mats

Installation of Flexible and Firm Concrete Mats

Every project site has its specific needs and requirements.

Download and refer to these technical drawings as a guide for how to install the Concrete Mat,  However, your specific project may require engineer certified and designed specifications for application of this mat for your project.

Checklist for Installation of Flexible Concrete Mats

Handy Checklist for Installation of Flexible Concrete Erosion Mats

Every project site and team has its specific differences and requirements.

Download and refer to this checklist as a guide for some suggestions for successful installation of the Flexible Concrete Mat,  However, your specific project may require engineer certified and designed specifications, and steps not noted in this document. Please create your own team checklist. for your project, this is offered a an example and guide only..

Click to download pdf of the project checklist for your installation team

Tools for Installation of Concrete Mats

A guide for which tools and equipment can be used for installation of Flexible Concrete Erosion Mats.

Gloves
Zip Ties
Hand Hooks
Hand Tools
Clevis
Portabe Concrete Cutting Saw (if cutting)
Rigging
Lifting Straps
Smooth Bucket
Excavator
Skid Skeer

Permanent erosion protection and prevention