8/10/2019 Spec Paving Pavement

1/5

Specification

Specification

15-43

Preamble to Section 8 & 9 Block Paving, Kerbs and Footways

It should be noted that in large areas of Oxfordshire the geological strata is Oxford, Gault and

other clays. Clays are subject to shrinking and heave, depending on the amount of pore water.

Where any footway/cycleway is founded on any clays, then the normal construction will be

modified to take account of the clays.

It is the County policy, and in line with District Council policy, that development are

constructed using high grade materials, therefore, it is essential that all kerb types are

considered, not just the normal pre-cast concrete. It should be noted that in Conservation

Areas natural stone products are the most likely material to be used, and special requirements

may apply in the Chilterns AONB area of South Oxfordshire.

8/10/2019 Spec Paving Pavement

2/5

Specification

15-44

Section 8 - Block Paving and Flags

801: General

Block paving may be used for all roads, footways, cycleways, pedestrian areas, access lay-

bys and adoptable parking areas. The design of pavements constructed with block pavingshall in general conform to BS 7533. Block paving shall be laid only by an approved

Contractor.

802: Materials

Paving blocks shall comply with BS 6717 Part 1 and BS 6677 having a work size thickness

of 65mm where used in non-vehicle trafficked areas and 80mm where used in carriageways,

lay-bys and parking areas and having chamfered wearing surfaces. The tensile splitting

strength of the blocks shall be 3.5 n/mm.

803: Sub-base

The sub-base material shall be Type 1 granular material complying with clause 602. The

finished surface level of the sub-base shall not deviate from the design levels by more than

10mm. The finished surface shall be free of any soft patches and shall be close knit so that

the laying course material cannot penetrate downwards. Where any soft patches are removed

they shall be replaced with Type 1 granular material. Under no circumstances may laying

course material be used to replace soft patches or for levelling the surface of the sub-base.

804: Road Base

Where the pavement construction is not completed before building construction commences

a road base shall be laid consisting of either dense bitumen road base complying with clause

606 or cement bound base complying with clause 607. The finished surface level of the road

base shall not deviate from the design levels by more than 10mm. Prior to laying the laying

course the roadbase shall be punctured on a 1m grid with holes of diameter < 50mm.

805: Laying Course

The laying course sand shall be in accordance with Table D2 of BS7533: Part 3: 1997 (Annex

D). The sand shall be precompacted with a plate vibrator and then levelled by screeding.

The surface level of the bedding/laying course shall be treated with an approved active pre

and post emergence residual weed killer, at the rate of spread recommended by the

manufacturer for total control. Special care must be taken near shrubs and trees, and

arboricultural advice sought.

The moisture content of the bedding sand needs to be a uniform 6-7%, it is therefore essential

that the sand should be stored in an area which is well drained and that it be kept covered

during periods of hot, dry weather or wet weather.

In some locations where a degree of rigidity is considered essential in the pavement surface,e.g adjacent to drainage furniture, the incorporation of 5.6% by weight OPC may be

permitted.

8/10/2019 Spec Paving Pavement

3/5

Specification

Specification

15-45

Only sufficient material for one day's work shall be prepared and in any case such that the

position of this boundary shall not be more than one metre from the laying face at the end of

the working period. Disturbance of the prepared laying course by pedestrian or wheeled

traffic prior to placing of the blocks shall be avoided.

The course shall have a minimum sand thickness of 30mm for a bound road base and 50mmfor a type 1 road base. The screeding of sand is very important and a surcharge of sand is

required from the start.

806: Edge Restraints

Edge restraint shall be provided at the perimeter of all paved areas and shall be adequate to

support traffic loads and prevent the escape of laying course material from beneath the paved

surface. Edge restraints shall consist of pre-cast concrete kerbs and channels complying with

clause 9 or approved made blocks. Where the block pavement abuts an existing structure, the

Engineer's approval shall be obtained before laying commences so that any necessary

strengthening or damp proofing precautions which the Engineer may require, can be carried

out prior to laying the block pavement.

807: Ironwork

Frames and covers for gullies and manholes in block paving areas shall comply with clause

317 and shall be properly bedded on clause 10.09 mortar in accordance with clause 320

before laying commences.

Frames and covers for gullies and manholes in block paving areas shall comply with the

requirements of clause 317 and shall be without flanges, and shall be set 5mm lower than thefinished block level. There shall be a minimum of one course of stretcher bond adjacent to

all ironwork with the aim to have flush. A 300mm to 500mm wide piece of a suitable filter

geotextile shall be laid under the laying sand and up the face of any ironwork or cover slab

to prevent the migration of the laying sand.

808: Bond

The blocks shall be laid hand-tight working from an existing face or edge restraint and shall

be laid to a herringbone pattern in carriageways. Stretcher bond shall only be used in footway

and non-trafficked areas.

Block shapes designed to assist with the formation of boundaries and with changes of

direction may be incorporated as appropriate. Full blocks shall be laid first, closure units

shall then be laid. Each area shall be completed as far as possible in full block units. Infilling

to boundaries and obstructions shall proceed as the laying course proceeds and shall be

completed before compaction commences. Alignment of the blocks shall be checked

periodically and adjustments made where necessary to achieve straight joint lines.

809: Road Base

In agreement with the Engineer the developers are permitted to omit laying the blockwork

until after building words are completed. In such cases the top 75mm of sub-base shall be

replaced with dense bitumen macadam binder course. Prior to laying of the blockwork the

base shall be cleaned, if the surface is in a poor condition the base course shall be removed

8/10/2019 Spec Paving Pavement

4/5

Specification

15-46

and replaced with MOT Type 1 granular material to the correct level. If the DBM binder

course remains it shall be punctured as Clause 804.

810: Trimming

Block shall be trimmed to shape and size in order to form boundaries and to work aroundobstructions. Where trimming is required it shall be carried out using an approved block

splitting device or a powered concrete saw. No part of a block of less than one half of a whole

block in size shall be used. Where it is unavoidable to fit the blocks neatly up to an

obstruction with the Engineer's approval an in-situ granolithic concrete fillet may be formed.

The granolithic concrete shall consist of one part OPC, one part of fine aggregate and 2 parts

of 10mm granite chippings measured by volume. Wherever in-situ concrete is used, careful

selection of fine aggregate and colour pigment is required to achieve a colour match with the

blocks. Such fillets are only acceptable with a minimum 120mm width and depth.

811: Compaction

The blockwork surface shall be compacted by a plate compactor to ensure the filling of the

lower block to block joint by the laying course material and to produce an even surface finish.

The plate compactor used shall have a plan area of not less than 0.25m and shall transmit an

effective force of 75-100kN per square metre of plate area. The frequency of vibration shall

be within the range 75-100Hz.

Compaction shall follow completion of laying as soon as possible after each day's work and

shall be compacted to within one metre of the laying face. No other area shall be left

uncompacted at the completion of each day's work.

812: Joint Filling

After compaction of the blockwork surface jointing sand, free flowing silica sand complying

with Table D3 of BS7533: Part 3: 1997 Annex D shall be brushed into the joints and using a

plate vibrator compacted to refusal. The finished level of the sand shall be 5mm below the

top of the blocks. The sand shall contain no deleterious salts or other contaminants and shall

not stain the surface of the blocks.

Joint filling and final compaction shall be completed as soon as practicable after laying and

at the completion of each days work. No traffic shall be permitted on the block surface untilfinal compaction has been satisfactorily completed.

Note: A neoprene coated sole plate may be required on special surfaces

813: Sealer

Finally, an elastomeric prepolymer sealer shall be applied in accordance with the

manufacturer's instructions to the surface of the small element paving immediately after the

jointing sand has been brushed/vibrated in making sure it is evenly spread over the surface of

the paving and allowing it to completely fill the joints before being absorbed into the jointing

8/10/2019 Spec Paving Pavement

5/5

Specification

Specification

15-47

sand. Generally rate of spread varies between 2-3m/litre. No sealant shall be left to "pond"

on the surface of the slabs. Approved sealants are Nufins Blockseal, A.C.M. Paveseal or

Resiblock Ltd's Resiblock Superior.

814: Early Trafficking

Where during the period of early trafficking any movement of the surface course occurs the

blocks shall be removed as directed by the Engineer and the cause established. After remedial

work has been carried out to the Engineer's satisfaction, the disturbed area shall be

immediately relaid and recompacted in accordance with the requirements of the foregoing

clauses.

815: Construction in Inclement Weather

No laying of concrete blocks or laying course shall take place on frozen material in the lower

layer. No frozen material or material containing ice shall be used.

816: Precast Concrete Flags and Tactile Paving

Precast concrete flags shall be manufactured in accordance with BS7265 part 1 and shall

comply with Table 3 Type F(400 x 400) and shall have a work size thickness of 65mm they

shall be used in footways only.

Tactile flags for use on pedestrian approaches to uncontrolled crossings will be the modified

blister type as shown in Guidance on the Use of Tactile Paving Surfaces - DETR January

1999 and be buff, or contrasting colour, other than red. The arrangement of the flags shall be

shown in the standard drawings or those given in the Guidance.

The use of tactile flags constitutes a traffic sign and they shall therefore not be installed or

used in a non-standard way.

Use of the different tactile surfaces e.g Cycleway paving (bar pattern), Hazard warning

pavement (corduroy) and directional guidance paving (round ended bars) shall accord with

the County Council's "Street Furniture and the Street Environment - A draft Code of Practice

and Specification Guidance Note for Oxfordshire County".