3. Bonding Between Fibers and Matrix
The properties in fiber reinforced geopolymer depend on the performance
of fiber, fiber content, precursor of geopolymer and curing environment.
However, the interface between the matrix and the fiber plays a key role
in the overall mechanical properties of the composites. If the interface
is well bonded and the load can be transferred from the matrix to the
fiber with a high carrying capacity, fibers with inert surfaces will
also result in weak interface contact[31]. Regarding the interface
between fiber and matrix, many scholars have studied the interface
bonding zone between fiber and geopolymer by establishing mathematical
or physical models.
Fiber fracture and pull-out from the matrix are the two main failure
mechanisms of geopolymer. At the same time, the fiber will agglomerate
if the fiber content in the matrix is too high, thereby resulting in the
decrease of the matrix strength. Fig. 2 depicts the interface bonding
between different fibers and geopolymers.