Scientists from Ural Federal University have discovered that even small air voids in high-strength mortar that binds precast concrete structures reduce the earthquake resistance of buildings.
A source at the university said: "Modeling showed that the voids in the upper part of the bonding elements, i.e. the joints, act as strong stress concentration centers, which accelerates cracking of the concrete and increases plastic deformations in the reinforcing bars, ultimately leading to a deterioration of structural integrity. Calculations also showed that if 30% of the mortar is lost in the upper part of the joint, the load-bearing capacity of the building's structural column decreases by 31.63%. Thus, even with only 10% air voids in the mortar, the plasticity modulus (a crucial indicator of the building's earthquake resistance) decreases by at least 26%."
This study focuses on defects in mortar filling at GSC-type reinforcing bar joints, a technique commonly used in the assembly of reinforced concrete structures. These voids arise from improper grouting and often remain hidden, but they lead, even in the early stages of operation, to cracking and accelerated steel corrosion under loads, particularly during earthquakes.
Scientists emphasize that the transition to prefabricated construction requires improved quality control of connections, particularly mandatory verification of the complete filling of gaps between connection points. Without this, even modern, highly resistant materials cannot guarantee the stability of buildings in earthquake-prone areas.
The study was published in the journal Computer Modeling in Engineering Sciences
