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This paper presents an experimental research work to evaluate prestress losses in pretensioned 12 prestressed concrete. An experimental program including variables such as concrete mix 13 design, specimen cross-section size and concrete age at the prestress transfer was carried out. 14 Several pretensioned prestressed concrete prismatic specimens were made and tested using 15 the ECADA+ test method, based on measuring prestressing reinforcement force. In addition, 16 specimens were instrumented to obtain the longitudinal concrete strains profiles at any time. 17Measurements from both techniques were taken over one year. Measured prestress losses 18 included elastic shortening losses and time-dependent losses due to concrete shrinkage and 19 creep. A coefficient to account for the relationship between the prestress losses from the 20 measured prestressing forces and the actual prestress losses from concrete compressive strains 21 is proposed. The experimental results were compared with the predicted prestress losses using 22 methods from several codes. 23 Keywords 24Concrete, pretensioned, prestress loss, creep, shrinkage, transfer, strain 25 26 2

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This is a repository copy of Flexural creep of steel fiber reinforced concrete in the cracked state.

This work presented in this paper contributes to a comprehensive research into structural elements containing demolished concrete blocks (DCBs) with a distinctly larger size than conventional recycled aggregates. In this research, 51 cubic specimens made from DCBs and fresh concrete (FC) with a replacement ratio of 30% were fabricated and tested under uniaxial compressive loadings. Two parameters were considered -the cube dimension and the characteristic size of DCBs. The influence of the two factors on the compressive behaviours of normalstrength concrete cubes made from DCBs and FC was examined in terms of the combined cubic compressive strength, the modulus of elasticity and the strain at peak stress. Based on the test results, a formula is presented to describe the relationship between the characteristic ratio (i.e. ratio of the characteristic size of DCBs to the cube dimension) and the combined cubic compressive strength of the specimens made from DCBs and FC, and a model is proposed to predict the combined cubic compressive strength of the specimens with various cube dimensions and characteristic ratios. The following results were obtained. In the case that the characteristic ratio is constant, the combined cubic compressive strength of the specimens made from DCBs and FC decreases significantly with an increase in cube dimension, and the effect of cube dimension on the combined strength accords with both the size effect law and the modified size effect law for conventional concrete. The effects of both the cube dimension and the characteristic size of DCBs on the specimen's modulus of elasticity and strain at peak stress are limited. In the case that the cube dimension is kept constant, the combined cubic compressive strength of the specimens made from DCBs and FC decreases gradually with an increase in characteristic ratio; the influence of cube dimension on this trend is very limited. Both the established formulae and the proposed model agree quite well with the test results.