The doping technique in the interface zone treatment: fresh and old concrete connections

Abstract

In order for concrete structures to have an adequate lifetime it is necessary to assess their durability and also to consider their maintenance. This has encouraged the development of specific technologies to solve problems concerning deteriorated and damaged parts. This study analyses the behavior of the interface zone between fresh and old concrete after scraping the old concrete (physical treatment) and also using the doping technique (chemical treatment). The doping technique consists in dry powder or high performance paste impregnation followed by fresh concrete pouring, or direct pouring of fresh high performance concrete. The performance of that connection was evaluated through flexural tensile tests until failure. The tests were carried out on conventional concrete prismatic specimens (fck = 20 MPa). At the end of the tests the specimens were remolded. The results indicated that the failure in the remolded specimens occurred outside the interface zone and the flexure resistance values were the same when compared to the original values, showing the efficacy of the procedure for connecting fresh and old concrete.