Answer :
The term “base material” with respect to masonry fasteners refers to concrete, brick or block.
Concrete anchors are used to solve concrete fastening problems.
Concrete anchors are used to solve concrete fastening problems.
I believe the answer is: concrete, brick or block.
To put it simply, base material refers to the ingredients/substance that is used to build the structure of the fasteners. Different type of base materials would affect how strong the masonry fasteners would be and how difficult the fasteners to be used.