BSI 20/30388487 DC 2020
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BS 10948. The application and use of hot- and cold-applied joint sealant systems for concrete pavements. Code of practice
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 19 |
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | 30388487 |
| 3 | BS10948_Text |
| 6 | 1 Scope 2 Normative references 3 Terms and definitions 3.1 adhesion 3.2 ageing 3.3 application life 3.4 bond breaker 3.5 cohesion 3.6 compatibility 3.7 construction joint |
| 7 | 3.7 construction joint 3.8 contraction joint 3.9 cure 3.10 expansion joint 3.11 longitudinal joint 3.12 tied joint |
| 9 | 4 Joint selection considerations |
| 10 | 4 Joint selection considerations 4.1 The dimensions and geometry of sealants used in road and airfield pavements and other trafficked areas should be specified and should take account of the length of slabs between joints, and whether the joint is a contraction, tied or expansion joint. 4.1.1 When the joint sealant is compressed by closure of the joint it tends to bulge upwards since the volume of the sealant remains constant. For this reason, a sealant should be applied so that its top surface is below the level of the adjacent pave… 4.1.2 The bottom of the sealant should be prevented from bonding to the base of the slot so as to avoid high local stress concentrations when the joint opens or closes. For narrow joint slots which are often formed deeper than the required sealant dep… For wider slots, a bond breaker tape should be used at the base, since the slot is usually formed in the concrete to the required depth. 4.2 Types of sealant 4.2.1 Hot-applied sealants and cold-applied sealants should conform to BS EN 14188-1 and BS EN 14188-2, respectively. 4.2.2 Fuel-resistant sealants should be specified for locations where spillage or leakage is likely from parked aircraft or vehicles, or where aircraft or vehicles regularly come to a halt. Fuel resistance of hot- and cold-applied sealants should be a… 4.2.3 Sealants for use adjacent to asphalt surfaces should conform to the asphalt compatibility test given in BS EN 13880-9. 4.3 Factors affecting joint movement |
| 11 | 4.3.1 The temperature range adopted for the design of the joint should be based on meteorological records for the area in which the pavement is to be constructed. 4.3.2 Seasonal movements should be assessed when designing the joint. 4.3.3 The design and construction of the joints should seek to achieve uniformity of condition wherever possible, as joints in pavements with short slabs might not all move equally, and some might not move at all. 4.3.4 Clause 5.4.6 advises that new concrete should be allowed to cure for a minimum of 14 days before joint sealing; mix design and climate permitting, this should allow sufficient time for the concrete to develop the required strength, water or humi… 4.4 Methods of formation of joint slots 4.4.1 Wet-formed joints 4.4.2 Sawn joints |
| 12 | 4.4.2 Sawn joints 4.5 Geometry and size of sealant 4.5.1 Width of sealant 4.5.2 Depth of sealant 4.5.3 Recess joints (Depth to top of sealant) 5 Joint slot preparation |
| 13 | 5 Joint slot preparation 5.1 Joint slot formation 5.1.1 The joint slot faces should be of sound, well-formed concrete. The joint slot should be widened if defective or contaminated concrete is encountered in the original joint slot faces. 5.1.2 The resulting joint slot faces should be plane and within 10 of the vertical. The maximum difference in width between joint slot faces at depths coinciding with the top and bottom levels of the sealant should be 2 mm. The joint slot width when … 5.2 Joint slot surface preparation 5.2.1 Debris from the formation of the joint slot should be removed, e.g. by water-jetting. Slurry remaining after sawing concrete can harden if left to dry out and should therefore be removed as soon as possible. 5.2.2 Temporary caulking material should be inserted into joints that have been prepared but not sealed, to prevent debris from entering the induced crack or formed joint. 5.2.3 Joint slot faces to which the sealant will bond should have any laitance removed and, since they are likely to be smooth and polished, should always be roughened to provide a surface which the primer and sealant can key into. A surface with a te… 5.2.4 The following methods of joint slot face roughening should be considered as being suitable for removing laitance and providing a roughened surface: 5.2.5 As final preparation for sealing and prior to priming where necessary, the joint slot should be thoroughly cleaned using oil-free compressed air at a maximum pressure of 0.5 N/mm2. 5.3 Joint filler 5.3.1 A joint filler or bond breaker tape, or both, as recommended by the sealant manufacturer, should be inserted without twisting and should be firmly located so as not to become displaced before or during sealant application. 5.3.2 Where bond breaker or joint filler is applied after cleaning and priming, contamination of the slot faces should be prevented. 5.3.3 The depth of the top surface of the placed joint filler should equal the required sealant depth plus the required distance between the top surface of the sealant and the adjacent pavement surface, within a tolerance of ± 2 mm. |
| 14 | 5.3.3 The depth of the top surface of the placed joint filler should equal the required sealant depth plus the required distance between the top surface of the sealant and the adjacent pavement surface, within a tolerance of ± 2 mm. 5.3.4 The primer and sealant should be compatible with the bond breaker tape or joint filler material used. 5.4 Priming 5.4.1 The recommended primer used should be as named on the certificate, required by BS EN 14188-1 and BS EN 14188-2, as appropriate. It should provide a visual indication of its presence. 5.4.2 Any primer should be applied to the joint faces by spray or brush as soon as possible after surface preparation. Primer should be applied carefully so that the joint surfaces are continuously and evenly coated. Pools of excess primer should be a… 5.4.3 At the time of priming, where recommended, the prepared joint slot should be clean and dry. Joints should be primed when the adjacent concrete has sufficient strength. 5.4.4 The moisture content of the concrete surface should also be considered. The moisture content at the concrete surface should be sufficiently low so that it does not detrimentally affect the bond of the primer or sealing material. See 5.4.5 for ad… 5.4.5 When condensation occurs in the joint slots following cool nights or when the joint slots are wet due to recent rain, suitable dry conditions for priming may be achieved by the application of heat to the joint by hot compressed air or by infra-… 5.4.6 Consult the technical data sheet or directly with the manufacturer for guidance on the minimum safe application temperature of the primer, particularly if working in cold climates or over-night. Joint faces must be frost free. Be aware of the … 5.4.7 Heating the concrete in cold weather to raise its temperature to a suitable level for priming is not recommended because the heat will quickly be lost, and at low temperature there is an increased risk of condensation in the joint slot. The cur… 5.4.8 The primed joint slot should be protected from weather, dust and any other contamination until the sealant is applied. The primed joint slot should not be heated or reheated after priming. |
| 15 | 5.4.8 The primed joint slot should be protected from weather, dust and any other contamination until the sealant is applied. The primed joint slot should not be heated or reheated after priming. 6 Sealant application 6.1 General 6.2 Heating hot-applied sealants 6.2.1 For un-primed joints, the sealant should be applied to the prepared joint when it is dry, and the temperature of the concrete is above the minimum specified in BS EN 14188-1 for the type of sealant. The concrete should remain above the minimum … 6.2.2 The recommendations and advice in Clause 5.4 concerning priming should also be applied to sealing where no primer is used. Additionally, advice can be sought from the sealant manufacturer. 6.2.3 The sealant should be heated indirectly using temperature-controlled equipment fitted with thermometers on heating and storage vessels. The sealant should be continuously agitated to avoid local overheating throughout the heating and pouring/mac… 6.2.4 The sealant should be heated to and maintained within the manufacturer’s recommended application temperature range and should be applied into the sealing slot within this range. Regular temperature checks should be made at the nozzle. Type F1 (s… 6.2.5 The performance of a hot poured sealant is crucially dependent on it being heated within safe temperature ranges and period, which should be as recommended by the manufacturer and as given in BS EN 14188-1. 6.2.6 Sealants which are not permitted to be re-melted, should be discarded at the end of a working shift. 6.3 Mixing multi-component cold-applied sealants 6.3.1 The sealant should be applied in accordance with the manufacturer’s instructions using meter mix dispense equipment specifically designed for that purpose. Alternatively, a power mixer should be used for sufficient time to produce a homogeneous … |
| 16 | 6.3.2 After mixing, the sealant should be applied into the sealant slot within the times stated by the sealant manufacturer for the application life of the sealant. 6.4 Application of hot and cold applied sealant 6.4.1 The sealant should be applied so that the top surface of the cooled or cured sealant is the required distance below the surface of the adjacent pavement surface as given in sub-Clause 4.5.3 within a tolerance of ± 2 mm. Where the pavement surfa… 6.4.2 The minimum depth of the sealant should be not less than the depth recommended in Clause 4.5.2 and measured in accordance with Clause 7.5. 6.4.3 The sealant, until solidified or fully cured, should be protected from damage caused by weather, dust and any other contamination. When necessary, the sealant may be trafficked at the end of the cooling or tack-free period, but guidance should b… 6.4.4 The cure times of cold-applied sealants are likely to vary according to ambient temperature. Automatic mixer/dispenser machines allow two component sealants with very short cure times to be used which is advantageous in reducing the time during … 6.4.5 The flow requirements in BS EN 14188-1 and BS EN 14188-2 help to ensure sealants that are self-levelling, do not flow downhill on crossfalls up to 2.5 %. Where the crossfall is steeper than this, e.g., on super-elevated road pavements, additiona… 6.4.6 The purchaser should include details as given in BS EN 144188-1 and BS EN 14188-2, at the time of enquiry or order, where the crossfall is steeper than 2.5 % or the joints are wider than 20 mm. 7 Site testing |
| 17 | 7 Site testing 7.1 Samples of the sealant components may be taken by the purchaser at any time and should comply with BS EN 14188-1 or BS EN 14188-2, as appropriate. 7.2 Where required by the purchaser, samples of liquid sealant should be taken at the point of application to check that the components have been mixed correctly. The sample rate should generally be not less than one per 1 000 m of joint, or not less … 7.3 Samples of applied sealant should be cut from joints to check that the sealant has been applied correctly in accordance with Appendix A. Joints should be sampled at a rate of not less than one per 1 000 m of joint, or not less than one per day’s … 7.4 The void formed by sampling should be refilled with the same product as the material sampled. 7.5 Depth measurements should be taken to the top surface of the installed bond breaker or joint filler, and the top surface of the sealant. Measurements should be taken at three locations along a transverse joint, or at 1 m spacing. The locations sho… 8 Resealing 8.1 The manufacturer’s recommendation should be followed regarding the installation of the new sealant system. 8.2 The old sealant should be removed and surfaces re-prepared to the conditions recommended in Clause 5.2. 8.3 New sealant systems should be compatible with the old sealant, but particularly for cold-applied materials to avoid problems of adverse reaction which can arise if any part of the old sealant remains on the joint slot faces. 8.4 Where it is apparent that the degree of movement in a joint has been sufficient to overstress the existing sealant, the joint slot width should, if appropriate, be increased so as to reduce the strain in the replacement sealant. It may also be nec… 8.5 The joint should be resealed as recommended in Clause 6. |
