A.2/3,2%,3%B.1/3,1%,1%C.2/3,3%,2%D.2/3,1%,1%
A.C15,100mm B.C25,100mm C.C20,120mm D.C30,120mm
A.7d,8MPa B.5d,5MPa C.7d,7MPa D.7d,5MPa