Building blocks of society
Building block
Oxford:

1 child's toy
积木
2 figurative
(basic element)
基础成分
the basic building blocks of matter
物质的构成要素

构成要素 seems to be the winner here.
Results for 社会 + 构成要素 on baidu give us a bunch of different sentences that use this pattern:

什么是社会?它的构成要素有那些?

第三章 社会及其构成要素

论社会的构成要素

...理解中国人的心理与行为_中国传统社会的构成要素(上)...