Truckcell – Design & Installation Guidance for Gravel Surfaces

Truckcell® Porous Aggregate Surface

Truckcell is a recycled plastic, cellular porous paving solution for use in Sustainable Drainage Systems (SuDS). Truckcell is suitable for a wide range of trafficked applications where a stabilised, free-draining surface is required and where high vehicle loads are expected. Typical applications include: coach and truck parks, emergency access and maintenance routes. Considerations relating to the movement and attenuation of water within the porous pavement are not covered in this document. This document is intended to be a summary presenting typical solutions. Contact ABG for site specific advice.

Installation and design guidance for ABG Truckcell heavy duty porous pavers for permeable gravel surfaces

Installation and design guidance for ABG Truckcell heavy duty porous pavers for permeable gravel surfaces

Truckcell® installation process

The following generic guidance must be read in conjunction with the specific project specification within the contract documents and the design notes below.

Truckcell heavy duty porous paving for grass surfaces installation process

1. Install the specified lower filter/separator geotextile and subbase stabilisation onto the prepared subgrade formation.

2. Install the specified subbase and edge restraints.

3. Install the upper ABG Terrex NW9 filter/separator geotextile on top of the subbase (optional).

4. Install the specified bedding layer to a uniform thickness.

5. Ensure an accurate right-angled Truckcell™ laying pattern by setting-out the site using string-lines. Check the lines regularly for accuracy. Start installing the Truckcell™ blocks. Wherever possible start laying from a right angled corner and progress across the site in rows. The blocks can be installed in a width or lengthwise orientation and cross-bonded if required or appropriate to fit the site. When installing the interlocking type blocks (80mm thick) ensure that the male/female connectors are fully located together. Use protective gloves to avoid abrasions.

6. Truckcell™ Pavers can be cut to fit around obstructions & curves using a hand or power saw. Wherever possible avoid using small cut-pieces less than one-third original size.

7. Fill the cells with the specified angular aggregate, so that the finished level is at the top of the cells. A single pass with a light vibrating plate machine or roller may be used to firmly bed the pavers and settle the fill. Top-up the cells with aggregate as required after settlement. It is preferable not to overfill the cells with aggregate. The use of rounded pea gravel/shingle is not recommended.

8. The surface may be trafficked by slow moving plant during the cell filling process, but care must be taken not to displace the open celled grids.

9. The surface may be trafficked immediately after the cells are filled.

10. A routine management and maintenance programme, to keep the surface in good condition and free of debris and weed growth, will help to sustain the porosity, quality and longevity of the system.

Notes

a. Advice on subgrade CBR% strengths, ground conditions, and construction over weak ground is available from ABG.

b. Alternative ABG stabilisation geosynthetics may be used in lieu of ABG Abgrid geogrid. These include ABG Gridtex Type 2 highstrength woven geotextile or ABG Abweb geocells. If the subbase stabilisation is omitted, the total subbase layer thickness (‘D’ on Table 1) is typically increased by a minimum of 50%.

c. A permeable open-graded (reduced-fines) aggregate is recommended, such as DTp Type 3 low-fines roading aggregate, or BS 7533-13:2009 SuDS aggregate (4/20 or 4/40). However, where a conventional DTp Type 1 subbase is to be used, it is essential that a drainage system such as ABG Fildrain is incorporated. Specific advice is available from ABG.

d. Maximum subbase particle size should match minimum subbase thickness, but must not exceed 75mm diameter. For subbase thicknesses of around 100mm, a minimum 37.5mm particle size should be adopted to allow effective installation of the Abgrid.

e. Typical paving edge restraint solutions include: concrete, timber, railway sleepers, steel and heavy-duty plastic.

f. The subbase may be overlaid by an ABG Terrex NW9 geotextile to provide enhanced water treatment function if required.

g. To provide a stable bedding layer for Truckcell, the bedding layer must not be sand.

h. The maximum advised gradient for vehicular trafficked applications is 8% (1:12) 5°.

i. When designed in accordance with the recommendations, Sudspave complies with BS8300:2009 : “Design of buildings and their approaches to meet the needs of disabled peopled” – Code of Practice (ISBN 9780 580 57419) & Building Regulations Document ‘M’ Section 6.

j. All stated dimensions & weights are nominal and in accordance with manufacturing +/- tolerances. Truckcell manufacturing tolerance +/-1.5%.

k. The recommendations in this document are only suitable for use with ABG products.

Table 1: Truckcell® typical DTp Type 3 sub-base thickness (D) requirements – refer to specific construction drawing

Vehicle Load & Frequency CBR (%) strength of subgrade soil (Table 2) (D) DTp sub-base thickness (D, mm) Abgrid Geogrid
Light vehicles with emergency HGV access 6+ 100 20/20
=4-6 100 20/20
=2-4 120 30/30
=1-2 220 30/30
Light vehicles with one HGV per week 6+ 125 20/20
=4-6 150 20/20
=2-4 200 30/30
=1-2 325 30/30
Light vehicles with 10 HGV’s per week 6+ 165 20/20
=4-6 200 20/20
=2-4 275 30/30
=1-2 425 30/30
Regular HGV access 6+ 200 20/20
=4-6 250 20/20
=2-4 350 30/30
=1-2 500 30/30

Table 2: Field guidance for estimating subgrade shear strengths

CBR (%) DCP Result 1 (Sandy Soils) HSV Result 1 (Clayey Soils) Tactile (Clayey Soils) Visual (Clayey or Sand Soils)
1 <1 <30 kPa Easily indented by fingers Adult standing will sink >30mm
1-2 <1 30-60 kPa Indented by strong finger/thumb pressure Adult standing sinks 10-30mm
2-4 1-2 60-120 kPa Cannot be indented by thumb pressure Utility truck ruts 10-25mm
5-7 2-3 120-200 kPa Can be indented by thumb pressure Loaded construction vehicle ruts by 25mm
>8 >3 >200 kPa Difficult to indent by thumb nail Loaded construction vehicle ruts by <10mm