macro cracks造句

the failure of concrete is caused by the formation, growth and confluence of crack, then creating the macro cracks in concrete
研究表明混凝土的开裂，首先起源于骨料和砂浆的粘结界面，进而发展至砂浆中。
It's difficult to find macro cracks in a sentence. 用macro cracks造句挺难的