Joints in concrete July 23, 2019 By Allan For my concrete plan and elevations what lines and codes should I use for concrete joints? Joints can be shown as follows: Joint type Abbreviation Linetype Construction joint—general CJ Construction joint—straight CJ(S) Construction joint—dowelled DCJ Construction joint—keyed KCJ Isolation joint IJ Contraction joints—keyed KJ Contraction joints—dowelled DJ Contraction joints—sawn or trowelled joint SJ Expansion joints —dowelled DEJ Expansion joints —keyed KEJ