Did these additions to the Constitution provide justice to Black Americans after the Civil
War?

No,

Explanation:

After the civil war offer, the United States government added several additions to the constitution:

13th amendments : To prohibit slavery in Untied States

14th amendments : Give former slaves the right to obtain citizenships and protection under the law

15th amendments: Give African Americans the right to vote.

But after all those amendments were created, the southern government invented a new way to discriminate African Americans. It's called the segregation laws.

segregation laws separate the public infrastructure between white and black citizens, but black citizens only has access to public infrastructure with lower quality.

what