Analisis parametrico de las variables que influyen en el comportamiento adherente de las armaduras pretesas en el hormigon

Prestressed concrete technique through the use of prestressed reinforcement is extended in the precast concrete industry. This technique consists on casting a concrete element over a previously prestressed reinforcement, proceeding to release once the concrete has reached a determined strength so the prestressed stress introduced to the reinforcement be transmitted, by bond, to concrete.; The bond behaviour of prestressed reinforcement includes two phenomena: prestress transmission from the reinforcement to concrete and anchorage of the reinforcement. This bond behaviour is characterized by mean of two lengths: transmission length and anchorage length. The good design of these lengths is a basic and fundamental aspect in the project of precast prestressed concrete elements to guaranty the appropriate transmission of prestress and to allow the anchorage of the reinforcement along the structural element service life.; The influence of the parameters related to the concrete dosage on the transmission and anchorage lengths of prestressing strands have been analyzed.; The ECADA test method has been applied. With this method the operations of transmission of prestress and anchorage of the reinforcement are sequentially done. The transmission and anchorage lengths are determined from the force control supported by the reinforcement testing series of specimens with different embedment lengths.; The differentiation of the concepts of anchorage length without slips and with slips has been proposed. The relationship of the parameters of dosage with the bond stress and the registered slips during the processes of transmission and anchorage has been studied. Expressions to value the slips distribution of the reinforcement in the transmission zone and in the anchorage zone have been proposed. A study on the determination of the transmission length from the free reinforcement slip end has been done and the viability to experimentally determine the transmission length from the slips sequence in the pull-out end as a function of the embedment length has been verified. The experimental results have been compared with results and predictions from other authors and standards, and an expression to calculate the transmission length have been proposed. Finally, the bond behaviour of self-compacting concretes has been compared with the bond behaviour of traditional concretes.