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1. Purpose
1.1 This fabrication and erection specification defines the materials and workmanship for the construction of road works.
2. Scope
2.1 This specification applies to the construction of all roads, parking areas, turning areas, and liquid loading bays on plants designed by Air Products Europe.
3. Related documents
3.1 Air Products Engineering Documents M10 Concrete and Reinforcement M15 Drainage and Underground Service Pipes 4ECE-M18 Earthworks
4. definition
4.1 The sub-base is the lowest layer of the road construction.
4.2 The sub-grade is the level in the ground on which the sub-base of the road construction is built. This is sometimes referred to as the formation level.
4.3 The road-base for flexible roads is constructed directly on top of the sub-base.
4.4 Surfacing refers to the one course wearing coat or two course coat (one base course and one wearing course) applied to the top of the road-base.
4.5 In the case of concrete construction, the concrete slab is the road-base and the surfacing.
5. GENERAL
5.1 Alternatives: In addition to quoting in their tender for the roads specified herein and/or on the drawings, the Contractor may, when they feel an alternative method of construction will be advantageous to Air Products, submit with their tender a full specification of their alternative proposal to Air Products for approval.
5.2 Employment of Specialist and Specialist Equipment: The Contractor shall employ persons with specialised road experience to supervise the work, and shall use equipment specially designed for the execution of the works.
6. ALIGNMENTS AND LEVELS
6.1 All horizontal alignments shall be constructed to ± 20 mm of the dimensions specified.
6.2 The level of road-bases just prior to surfacing shall be within ± 20 mm of the levels specified. In addition, no part of a 3 m long straight edge laid on the surface shall depart from the base by more than 15 mm.
6.3 The levels of base courses and wearing courses after rolling shall each be within ± 10 mm and ± 5 mm respectively of the levels specified. In addition, no part of a 3 m long straight edge laid on the surfaces of either course shall depart by more than 10 mm and 5 mm respectively.
7. INCLEMENT WEATHER
7.1 Laying of any part on a road shall not continue during heavy or continuous rain, nor shall laying take place on frozen ice bound surfaces. All standing water shall be removed before laying starts or recommences.
7.2 Laying of materials containing tar or bitumen binders, or mixtures thereof, shall cease if the temperature of the air is at or falls below 2°C.
7.3 Concreting in cold conditions shall be in accordance with M10.
8. TRAFFIC ON ROADS
8.1 The Contractor shall ensure that all construction traffic used on roads under construction does not damage the sub-grade or the materials already constructed.
8.2 The wheels or tracks of plant moving over the various courses shall be kept free from deleterious materials such as mud or slag.
8.3 No vehicular traffic shall be run on any surface, or layer until the curing period for the material has expired and at least two days elapsed since its final rolling, or such further period as may be decided by the Engineer.
8.4 When construction traffic is run on flexible roads, the wearing course shall be delayed until the end of the construction period. Prior to laying the wearing course, the base course shall be cleaned and sprayed with a tack coat.
8.5 When it is necessary for heavy mechanical erection equipment to be located in areas of rigid roads, the concreting shall be delayed until the end of the erection period. After use and before placing the concrete, the sub-base shall be cleaned and restored to the condition originally specified.
9. EXCAVATIONS FOR BURIED SERVICES
9.1 Excavations for buried services shall generally be in accordance with M15 and 4ECE-M18. The Contractor shall be responsible for the complete reinstatement of all excavations to the satisfaction of the Engineer.
9.2 Road construction and surfacings will be reinstated to match the existing road construction, unless otherwise ordered by the Engineer.
10. SUB-GRADE
10.1 Prior to covering the sub-grade with the sub-base, the sub-grade shall be prepared and the surface treated and protected in accordance with 4ECE-M18.
10.2 After removal of the protective layer and immediately prior to laying the sub-base, the sub-grade shall be inspected, and any soft or unsuitable areas of sub-grade shall be removed and replaced with the specified sub-base material, which shall be compacted as specified for sub-base material.
11. SUB-BASE AND TEMPORARY ACCESS ROADS
11.1 Material: The sub-base shall consist of crushed granular material graded from 75 mm to dust for maximum compaction. When any part of the sub-base fails to comply with this clause, the sub-base shall be removed and replaced as directed by the Engineer.
11.2 Laying: The sub-base shall be laid and compacted in equal layers not exceeding 200 mm thick. All material shall be placed and spread to an even depth without delay.
11.3 Compaction
11.3.1 Compaction shall be carried out using not less than eight passes of vibrating roller, having static load per metre width of 2.5 to 4.5 tonnes.
11.3.2 Compaction shall be completed as soon as possible after the material has been spread.
11.3.3 On completion of compaction, the surface of any layer of material shall be well closed, free from movement under compaction plant, and free from compaction planes, ridges, cracks or loose material. All loose, segregated, or otherwise defective areas shall be made good to the full thickness of the layer and re-compacted.
12. FLEXIBLE ROAD BASE
12.1 Material: The road base shall be constructed using hot rolled asphalt, graded for maximum density using a maximum stone size of 32 mm.
12.2 Laying: All material shall be placed and spread to an even depth without delay.
12.3 Compaction: Compaction shall be not less than eight passes of a smooth wheeled roller, having a weight per metre width of roll of more than 5 tonnes, and shall be completed as soon as possible after the material has been spread.
12.4 Depth of Road Base: The thickness after compaction shall be as shown on the drawings, but shall not be less than 60 mm.
13. ROAD SURFACINGS
13.1 Materials
13.1.1 General: Surfacings may be constructed in two courses.
13.1.2 Wearing Course and Base Course: Surfacings shall be hot rolled asphalt made and laid to produce a road surface of a quality suitable for heavy traffic.
13.1.3 Tack Coat: Tackcoats shall be a suitable grade of bitumen emulsion applied at a uniform rate of spread of 1.8 to 3.0 sq. m. per litre.
13.2 Workmanship
13.2.1 Tack Coats: Bitumen emulsion tack coats will be sprayed on the road-base well in advance of the surfacing and if practical, up to 24 hours beforehand. If necessary, it shall be blended with fine sand.
13.2.2 Laying
13.2.2.1 Basecourse material shall be covered by the wearing course within three consecutive days of laying, except when it is to be used by construction traffic. When the laying of a course has been delayed to allow use by construction traffic, the previous course shall be cleaned and repaired to the original specification.
13.2.2.2 Materials shall be transported in clean vehicles and shall be covered over when in transit or awaiting tipping.
13.2.2.3 The mixed material shall be supplied continuously to the paver and laid without delay. The delivery of material shall enable the paver to be operated continuously.
13.2.2.4 The paver shall provide an even and uniform flow of material across the full laying width, free from dragging or tearing of the material and with minimum segregation.
13.2.3 Compaction
13.2.3.1 Material shall be compacted as soon as rolling can be effected without causing undue displacement of the mixed material. The material shall be uniformly compacted by an 8 to 10 tonnes smooth steel-wheeled roller having a width of roll not less than 450 mm.
13.2.3.2 The material shall be rolled in a longitudinal direction from the sides to the centre of the road, overlapping on successive passes by at least half the width of the rear roll.
13.2.3.3 Rollers shall not stand on newly laid material.
13.2.4 Chippings
13.2.4.1 Chippings shall be applied to the final surface, and shall be spread uniformly after the surface has had its initial compaction, but before its final compaction. Chippings shall consist of 12 mm clean, hard stone, coated before application with 2–3% asphaltic cement of 40 to 50 penetration at 25C.
14. RIGID ROADS
14.1 Materials
14.1.1 Concrete
14.1.1.1 All rigid roads shall be in reinforced concrete and shall be in accordance with M10, unless specified otherwise in this specification.
14.1.1.2 Concrete shall be a designed mix with 28 day cube strength of at least 30 N/mm2 and a cement content of at least 320 kg/m3. Also, it shall be air entrained between 4% and 6% volume.
14.1.1.3 The water cement ratio shall not exceed 0.5.
14.1.2 Reinforcement: Reinforcement shall be a square mesh fabric providing at least 3.9 kg/m2. Reinforcement shall be delivered to site in flat mats.
14.2 Workmanship
14.2.1 Placing Concrete: When concreting has commenced, no cessation of the work will be allowed until the concreting is completed up to the next expansion joint. In the event of mechanical breakdown or adverse weather, the Engineer or the Engineer’s Representative may permit the use of a construction joint.
14.2.2 Treatment at Manholes: Manhole covers and frames shall be housed in separate small slabs of the same dimensions as the exterior of the manhole shaft. The slabs shall be bounded by expansion joints.
14.2.3 Compaction and Preliminary Finish: Concrete shall be compacted and finished by a machine designed and constructed specifically for road construction.
14.2.4 Final Brush Finish: This final finish shall be applied by lightly dragging a stiff wire brush across the surface in the direction of the drainage just prior to setting.
14.2.5 Curing
14.2.5.1 After finishing, the exposed surfaces of concrete shall be covered immediately with polythene sheets firmly held down at the edges to retain the moisture. Alternatively, the surface may be treated with an approved curing compound. This shall be mechanically sprayed on the surface at the rate of 4 to 5 m2 to the litre using a fine spray.
14.2.5.2 Any groove over a joint shall be protected from the entry of curing compound.
14.2.6 Reinforcement
14.2.6.1 The reinforcement shall be so placed that after compaction of the concrete, it shall be 50 mm below the finished surface of the slab.
14.2.6.2 Reinforcement shall overlap by not less than 450 mm nor not less than 60 bar diameters whichever is the greater.
14.2.6.3 Reinforcement shall be modified, as approved by the Engineer, to suit manholes and surface boxes, junction, or slabs of abnormal width or length.
14.3 Joints, Grooves, Fillers, and Sealers
14.3.1 Special Requirements for Liquid Oxygen Loading Bays
14.3.1.1 In the concrete loading bays around liquid oxygen fill points, the grooves of all joints except expansion joints shall be sealed with a portland cement based grout. Sealing shall be delayed until after 28 days from placing concrete.
14.3.1.2 At expansion joints in concrete loading bays, a filler of 25 mm compressed mineral wool board shall be provided 12 mm wide for the full depth of slab instead of grooves, filler, and sealer.
14.3.2 Arrangement of Joints
14.3.2.1 Unless otherwise agreed, all joints shall be as follows: Contraction joints shall be located at a maximum spacing in two perpendicular directions of 25 m. Expansion joints shall be located at a maximum spacing in two perpendicular directions of 100 m. All joints shall be straight and continue across the full width or length of the slab. Construction joints shall only be located when it is not possible to terminate the work at specific joints. They shall not be located within 3 m of other parallel joints.
14.3.3 Joint Details: Joint details shall be as shown on the drawings.
14.3.4 Grooves at Joints: Grooves shall be made at joints by either forming or sawing after the concrete has set.
14.3.5 Sealing of Grooves
14.3.5.1 When traffic is permitted to use the road before permanent sealing is in place, the joint grooves shall be protected by inserting a temporary sealing.
14.3.5.2 Permanent sealing of joints shall not be carried out until 28 days after placing of the concrete.
14.3.5.3 The joint shall be cleaned and scoured immediately prior to permanent sealing. The groove shall be air dry at the time of sealing.
14.3.5.4 Prepared joints shall then be primed and sealed with a hot poured compound, except as detailed in Clause 14.3.1.
15. KERBS
15.1 Kerbs shall only be provided when specifically detailed on the drawings. In all other cases, road edges shall be provided with hard shoulders.
15.2 Unless required otherwise, kerbs shall be half splayed precast concrete, 150 mm wide by 150 mm deep or 300 mm deep as required. For radii of less than 12 m, kerbs shall be preformed.
15.3 Kerbs shall be bedded on a 300 mm deep bed of concrete 300 mm side, and backed with a 300 mm wide haunch 75 mm from the top.
15.4 Joints between kerbs shall be filled and pointed with cement mortar, except for the joint nearest to the road expansion joint, which shall be 25 mm wide and filled with sealer.
16. WATERPROOF MEMBRANE
16.1 When required, waterproof membranes shall be approved polythene or similar sheet, with a thickness of 0.12 mm.
17. CONSTRUCTION PROGRAMME
17.1 When the road-base or wearing course are to be deferred until the completion of plant construction, the exposed sub-base or road-base shall be suitable for plant construction traffic, and is to be maintained in a suitable condition for ensuring continuous uninterrupted access to the construction site for the duration of the construction programme.
17.2 Immediately prior to final construction of the road-base and wearing course, the sub-base or road-base shall be cleaned, lost material replaced, repaired, and completed.
17.3 An application of a binder shall be supplied before the wearing course.