126 / 2022-04-27 16:25:24

Study on effect of internal swelling reaction in concrete on structural performance of prestressed concrete beams

Delayed Ettringite Formation; Alkali Silica Reaction; Concrete Expansion; Prestressed Concrete Beam; High Temperature at early ages

This study investigated the effect of DEF and combined ASR and DEF in concrete on the structural performance of Prestressed Concrete (PC) beams. The PC beam with the expansion by combined DEF and ASR or DEF in the concrete had many split cracks in the axial direction due to the concrete swelling. Although the flexural rigidity in the deflection direction decreased to some extent with increase of concrete swelling, it did not decrease significantly in the subsequent continuous expansion. It was observed that the combination of ASR and DEF (ASR-DEF) expansion in the test specimen leads to a slight decrease in the load flexural loading capacity of the PC beam even though compressive strength of cylinder specimen was less than 5 MPa. Although the small compressive strength indicates flexural compression failure at low load, the beams with large internal swelling finally failed at much higher load due to the flexural tension failure with concrete compressive crushing at top after the reinforcing bars yielded. The cracking pattern of DEF or ASR-DEF affected beams arising from the loading was the similar that of beam without expansion. Hence, it was identified that even large ASR-DEF or DEF expansion in concrete has a slight effect on structural performance in PC structures.