Glued connection for TCC slabs : Experimental and Numerical investigation

Abstract: Timber-concrete composite (TCC) structures are becoming more popular in several industrial applications as an efficient method for optimizing the structural performance and the cost of construction as well as lowering the emissions of carbon dioxide. TCC floors are more sustainable than pure concrete floors and more resistant to vibrations and excessive deflections than pure wooden floors. The effectiveness of a TCC floor is dependent on the connection between the materials. The stiffness and strength of the composite element increases by having a rigid connection. An example of a rigid connection is an adhesive-bonded connection, however obtaining a connection without slip is difficult considering there will always be certain amount of slippage in the connection. In this thesis adhesive connections are investigated with two different types of adhesive, one called Sikasil SG-500 and the other Sika PS. The application of the adhesives for the test specimen differ. Since Sika PS is a more fluid glue, a different approach was necessary than for the Sikasil SG-500. Five test specimen were tested of each adhesive by performing double shear push out tests and comparing the results to a numerical model, which was performed in ABAQUS. In the numerical model, the adhesive was created as a cohesive element. Furthermore the properties of the modeled adhesive was based on the experimental results for respective adhesive. The experimental results showed that both adhesives managed the estimated shear force in the serviceability limit state and the ultimate limit state and yet remained in the elastic region. Sikasil SG-500 turned out to be more flexible while Sika PS specimen resulted in higher shear strength. The short creep tests (30 minutes of a constant load) showed that the deformation increased more for Sika PS than for Sikasil SG-500. However both adhesives had large deformations after only 30 minutes. There was also a difference in the average longitudinal shear strength, where it resulted in 1.06 MPa for Sikasil SG-500 and 2.02 MPa for Sika PS. This study indicates that Sika PS is more preferable in TCC structures than Sikasil SG-500.