What Are the Causes of Concrete Cracks and Heaving?
Concrete cracking results from environmental and structural stresses. concrete image by Empath from Fotolia.com Cracking and heaving are common flaws in concrete. Because concrete is a mixture of cement, gravel and sand, it has a finite tensile strength that is prone to fracturing under environmental or structural stress. Concrete was used in natural forms by the Ancient Egyptians and Chinese. The Romans then invented synthetic concrete by mixing volcanic ash with lime mortar, sand and gravel. Modern or “Portland” cement was invented in the 19th century and is a mixture of chalk and clay which has been baked in a lime kiln. By the late 19th century concrete being was being reinforced with steel and iron. Cracking from Shrinkage Because hydration is required to bond concrete’s cementitious content, evaporation shrinks drying concrete. When this happens stresses develop, leading to cracks. Higher amounts of water in the concrete mix raises tensile stress during drying as more shrinkage o
