Rigid pavement joint openings and strain readings were monitored during a 4-month period in an attempt to understand pavement behaviour during joint formation. The displacement data recorded at each joint indicate when and where the joints were formed in the rigid pavement. The strain variations recorded indicate different stress states when a joint was formed some distance away from the gauges vs. close to the gauges. Data and conceptual analysis prove that the recorded strain variations are stress-dependent and reliable. The residual bending stresses measured in the tested slabs before a joint was formed were relatively high, at least in the range of 0.99MPa (143psi) to 1.26MPa (182.2psi). The existence of residual tensile stresses before a joint is formed may increase the slab's risk of cracking. Therefore, special analysis is needed if traffic loads must be applied on a newly constructed concrete pavement before joint formation.