Concrete Paving Day 2

BASE COURSE MATERIAL

• Should be crushed rock including particles of all sizes.  
• No particles should have a diameter more than one third of the thickness of the required base course layer.
• It should contain no soil or plant material.
• Lay geotextile fabric first where soft clay which might push into and through the base course material.
• For layers of 100mm thick of more, use 40mm all in aggregate.

 

Preparing The Sub-grade:

Even after excavating, the sub grade might have holes that need filling to bring it up to the desired level. Fill these with base material, and compact in layers no more than 100mm thick using a plate compactor or rammer.

The finished sub-grade level should match within 20mm, the contour of the finished paving

Preparing Base Course:

This should also be laid in layers no thicker than 100mm and compacted to a uniform dense condition, especially around manholes and kerbs. The finished texture of the base course should not allow bedding sand to filter through.

The final surface of the base course should match the contour of your finished paving with no bumps, and no holes deeper than 10mm.

Edging:

Wooden edging, two layers of 25mm timber

Soldier course of either standing or flat pavers

Paving kerb- segmented raised kerbing

Paving edge- concealed, underground PVC strip Haunching- concealed concrete strip.

Soldier course of standing pavers

 

Preparing Bedding Sand: 

Bedding sand supports your pavers, but will not hide irregularities in the base course. It should be damp but not wet, coarse river sand (not beach sand).

1. Don't compact bedding sand directly. It compacts under the pavers. To test how much the thickness will reduce, spread some sand over a small area. Laya paver on top, and thump that with a rubber hammer. The resulting reduction in sand thickness will tell you how much your sand compacts.
2. Pave in manageable sized areas. Spread sand only over an area you know you can finish in one session. Spread the sand to slightly more than the depth your rubber hammer test indicated would produce a compacted sand depth of between 20mm and 30mm. That will usually be 35mm to 40mm.
3. Screed the sand to a uniform level. As with any screeding, you need guides or runners at each side to run your screed board on. If you have already laid a soldier or kerb course, you may be able to use that to support your runners. If not, you'll need to drive pegs, and fix your runners to them, just like concrete boxing.