Why don't they just cConcrete anywhere that they have to Cement?
concrete will crack even when you joint it or cut it...its just that if you joint it correctly the cracks will take place in the joint and be less visable.. ncrete is just cement with stone aggregate added for economy...
These are called expansion joints----Concrete moves depending on temperature and will crack if it doesn't have a place to give a bit.
First; Cement is one component of Concrete. Second Concrete will shrink as it cures or hardens. The first cracks that you will notice are shrinkage cracks. Also, concrete expands and contracts with changes in temperature, joints must be created to allow for movement due to this expansion, these are know as expansion/contraction joints. You will feel these when driving over a concrete roadway or bridge deck. A Civil Engineer for 30 years
Cement is Portland Cement. One of only a few ingredients that comprise Concrete. The cracks as the CE said are contraction/control joints. As Concrete cures, hardens, the Concrete shrinks. The control joints are not the full depth of the Concrete, but rather only a few inches. These joints again as the CE said are for controlling the cracking of the Concrete. This along with the rebar that is embedded in the pad, keeps the Concrete cracking to a minimum, but lets the control joints do there job.
