Longitudinal Joint Design
See FHWA’s CRCP Design and Construction Guidelines for the references included in this page. A new, more comprehensive FHWA CRCP Design, Construction, Maintenance and Rehabilitation manual is currently under development and this page will be updated upon its release in the spring of 2016.
The use of longitudinal joints is recommended for pavements wider than 15 ft (4.6 m). Joints are typically located in between lanes and between a lane and a concrete tied shoulder. Tiebars or transverse reinforcement should be provided along longitudinal joints to prevent separation, and to maintain adequate joint transfer efficiency. Two types of longitudinal joints are commonly used in CRCP: construction and contraction joints.
Better practices for concrete pavement joints can be found in the IMCP manual and elsewhere. However, some typical sections of joints that have been used on CRCP pavements are given herein.
A longitudinal construction joint is specified when more than one pass is necessary to pave thetotal pavement width. In the past, it was recommended that trapezoidal or half-round keyways were formed along the longitudinal construction joints to increase its load transfer efficiency. However, some key joints have failed in shear resulting in spalling along the joint. In addition, the area along the keyway may be more susceptible to concrete consolidation problems. It is therefore recommended that tied butt joints be used instead.
Longitudinal contraction (hinged) joints ensure that longitudinal cracking on wide pavements occur along a fixed (weakened) plane. Longitudinal joints are created by performing a sawcut at the specified joint location to relieve the stresses generated in the trans- verse direction of the concrete due to volumetric changes.
Along these longitudinal joints, either transverse reinforcement or tiebars should be used to tie the adjacent slabs together and to maintain adequate load transfer efficiency. Reinforcement design should follow recommendations provided in Section 4.5.