I discussed a doctoral thesis at the College of Engineering at the University of Basra (Shear strength of indirectly loaded reinforced concrete beams poured with self-compacting concrete containing recycled concrete as coarse aggregate)

The thesis presented by the student Thamer Hussein Amer Al-Mousawi dealt with the classification of lintels into seventeen deep lintels with a cross section in the shape of the letter T of reinforced concrete, fifteen deep lintels of rectangular section, and six thin rectangular lintels. These lintels are divided into four groups, the first group includes twenty-four deep lintels Subjected to indirect loads and without shear resistance reinforcement The second group contains six deep beams subjected to direct loads and without shear resistance The third group includes six skinny beams subjected to direct and indirect loads The last group includes deep beams subjected to indirect loads with their containment On vertical shear armature

The thesis aims to conduct a laboratory and analytical study regarding the structural behavior of deep and thin reinforced concrete beams with a cross-section and a rectangular one.

The thesis concluded that the directly and indirectly loaded deep beams can bear additional loads

After the diagonal cracking due to the phenomenon of Arch action

The test results show that the presence of RCA causes a reduction in the amount of slant cracking and the maximum loads, where the maximum load decreased by 14%, 38%, and 42% when the RCA replacement increased to 25%, 50% and 75%, respectively, in the first group of deep beams.

As for the rectangular deep beams, the decrease was 2%, 23%, and 25% when the RCA substitution increased by 25%, 50% and 75%, respectively.