Structural elements of composite materials are widely used as them allow conceiving stronger as well as economic structures. In the case of wood-concrete composite slabs, the high compressive strength of concrete, together with the great performance and behavior of wood under traction, allows to obtain a resistance, weight and stiffness effective structure; features widely proven in indoor environments. The objective of this research is to model the behavior of wood-concrete slabs at an outdoor environment conditions in order to study its usage in walkways. To achieve this goal, the behavior of the wood-concrete slabs will be conducted through the use of finite element models that are going to be validated with the experimental data previously obtained from tests performed in two composite slabs, which were subjected to diverse loading configurations for 1250 days in outdoor environment (Pena, Fuentes, Fournely, Navarrete, & Pinto, 2015). According to the results, it was possible to conclude that real moisture is greater than the theoretical one, which promotes the decay of wood, nevertheless, this variation did not produce a significant change in the overall mechanical characteristics of composite slabs; in the other hand, numerical modeling demonstrated the importance of the connection transverse stiffness, besides enabling the incorporation of wood moisture effect over its mechanical properties, allowing to quantify the effect of the connection stiffness.