On the sum of two affine Cantor sets

Suppose that $K$ and $K'$ are two affine Cantor sets. It is shown that the sum set $K+K'$ has equal box and Hausdorff dimensions and in this number named $s$, $H^s(K+K')<\infty$. Moreover, for almost every pair $(K,K')$ satisfying $HD(K)+HD(K')\leq 1$, there is a dense subset $D\subset \mathbb R$ such that $H^s(K+\lambda K')=0$, for all $\lambda\in D$. It also is shown that in the context of affine Cantor sets with two increasing maps, there are generically (topological and almost everywhere) five possible structures for their sum: a Cantor set, an L, R, M-Cantorval or a finite union of closed intervals.