needs to be determined. In the model it was assumed that the radial crack spacing was

constant but it has been implied in the literature that the cracks at the outer layers of the

concrete are more severe. This could mean that the cracks are also closer together in the

outer layers.

 The length of the micro column was assumed to vary linearly across the two

identified regions (regions 1 and 2) of the cylinder becoming smaller towards the center

for simplification. A different relationship for the variation of the micro column length

can be explored such as a parabolic relationship. It should be noted that constant values

of the micro column length across the cross section were investigated but did not yield

any reasonable results.

 Another issue that needs to be addressed is the modulus of elasticity of concrete. In

this study the modulus was assumed constant but it is known that the initial modulus

varies for different concrete strengths. Empirical relationships that estimate the initial

concrete modulus depended on the design strength are available and could provide

estimations for the different concrete strengths.

 Another aspect of the model that might have an impact on the different parameters

used in this model is the amount of CFRP grid reinforcement. Only a few tests have been

conducted using a specific amount of the CFRP grid. More tests with increasing amount

of CFRP grid reinforcement are needed to validate the confinement model.

 The CFRP grid has not been used for this purpose before and its overall effect on

the behavior of concrete is somewhat different than the effect of other types of FRP

reinforcement. Therefore the findings from other studies do not necessarily apply to the

case of CFRP grid confined concrete.