The paper presents results from three large scale experiments on seven reinforced concrete panels obtained during an extensive experimental program. This was aimed at possible application of cement reduced (fly ash replaced) concrete in the production of precast segmental linings for tunnels created by a tunnel boring machine (TBM). In particular, this paper is focused on the comparison of fire...

We have studied the mechanism by which dispersed Y 2 0 3 exerts beneficial effects on the oxidation protection of an A1203 coating (film) on the basis of the following models: 1) Y2O3 suppresses surface segregation of S by trapping it in the alloy matrix and accordingly suppresses spalling of the A1203 film; 2.1) The diffusion of alloying elements into the N2o3 film is retarded by dispersed oxi...

This study focused on the residual strengths of reinforced concrete beams with heavy deterioration. This work is based on experimental investigation of reinforced concrete beams naturally corroded over 30 years. Visual inspection was firstly conducted and the concrete cracking, spalling of concrete cover, corrosion of rebar were recorded. Material tests on concrete and corroded rebar were also ...

A mathematical model allowing coupled hygro-thermo-mechanical analysis of spalling in concrete walls at high temperatures by means of the moving boundary problem is presented. A simplified mechanical approach to account for effects of thermal stresses and pore pressure build-up on spalling is incorporated into the model. The numerical algorithm based on finite element discretization in space an...

The use of a three dimensional Discrete Element Method (DEM) is proposed to study concrete submitted to flat rigid nose shaped missile impacts. Spalling, scabbing, penetration and perforation events are characterized by the model. The reduction in missile velocity is compared with real test cases made by the French Atomic Agency. The first results show a good agreement between the numerical and...

Corrosion of reinforcing and prestressing steel due to chloride attack is one of the major causes of deterioration of concrete structures. This is of most concern because of the associated reduction in steel cross-sectional area, spalling and loss of bond. In the case of prestressed concrete structures, the corrosion of prestressing strands can lead to a sudden failure due to higher stress leve...