Code of practice for installation of joints in concrete pavements
1985 Edition

Recommended joint spacing is influenced by factors such as thermal expansion, placing temperature, slab thickness, reinforcement, and subgrade friction. Transverse joints include expansion joints typically 20 mm wide, and contraction joints spaced according to slab properties. For reinforced slabs with expansion joints only, spacing varies from 45 m for 0.25 m thick slabs to 12.5 m for 0.10 m slabs. When dummy contraction joints are included, expansion joints range from 51 m to 30 m, with contraction joints from 17 m to 7.5 m. Unreinforced slabs have smaller contraction joint spacings around 4.5 m, with expansion joints spaced between 27 m and 36 m. Continuously reinforced concrete pavements use expansion joints only at ends or junctions, with elastic joints spaced every 4–5 m. Thicker airfield pavements permit wider spacing with appropriate sublayer treatment.

Dowel bars, made from steel conforming to IS 432 (Part 1)-1982, facilitate load transfer across joints while allowing horizontal movement and must be properly aligned and supported during concreting. Tie bars serve to hold slab edges together to prevent joint opening and are bonded across joints within the slab. Installation requires ensuring bars are clean, correctly spaced, and adequately supported to avoid displacement. Side formwork should be designed with openings to accommodate tie bars. Both dowel and tie bars must comply with relevant IS specifications and be installed following the prescribed alignment and cover requirements.

Joint fillers should be premoulded and resistant to decay and insect attack when buried, conforming to IS 1838 (Part 1) - 1983. Sealing compounds must meet Grade A requirements of IS 1834-1984, exhibiting strong adhesion without cracking or spalling. A primer complying with IS 3384-1965 is to be applied to enhance bonding. Sealants should be carefully poured to avoid spillage, and excess filler must be promptly removed to maintain joint integrity. These specifications ensure joints remain durable and weather-resistant throughout their service life.

For prestressed concrete pavements, steel-plate expansion joints with reinforced concrete subslabs and drainage channels beneath the joint plates are employed to accommodate significant movements. Joint plates are bitumen coated and separated by polyethylene layers to enhance durability. Continuously reinforced concrete pavements utilize steel-plate expansion joints at ends and transverse elastic joints with continuous reinforcement passing through the joint. A bond-breaking layer is applied on steel to permit movement, and grooves are filled with plastic or ply inserts, often not requiring sealing compounds due to limited movement. Expansion joints extend across the full pavement width and depth with filler thickness at least twice the maximum expected slab expansion, and dowel bars are provided for load transfer except at structural junctions.

Routine inspections should be conducted every six months, recording joint conditions such as cracks, sealant degradation, and dimensional changes. Maintenance involves removing debris and deteriorated sealant, thoroughly cleaning joint surfaces, and refilling with approved sealant materials. To prevent tackiness or material pick-up under traffic, exposed sealing compounds should be dusted with hydrated lime. Proper cleaning and sealing before traffic exposure, combined with maintaining vertical slab edges and appropriate dowel bar placement, help prolong joint service life and minimize deterioration.