Following are the issues concerned with chert:Chert has several problems when it is used as concrete aggregates. When chert gets weathered while it is used in concrete, it develops pop-outs that undergo freezing and thawing. This is due to the highly porous nature of weathered chert.Certain varieties of chert undergo a specific reaction with highly alkaline types of cement. This leads to expansion and cracking of concrete which leads to failure of chert.