No abstract

No abstract

A conceptual model for the prediction of the shear-flexural strength of slender reinforced concrete beams with and without transverse reinforcement is presented. The model incorporates the shear transferred by the un-cracked concrete chord, along the crack's length, by the stirrups, if they are, and, in that case by the longitudinal reinforcement. After the development of the first branch of the critical shear crack, failure is considered to occur when the stresses at any point of the concrete compression chord reach the assumed biaxial stress failure envelope. A physical explanation is provided for the evolution of the shear transfer mechanisms, and the contribution of each one at ultimate limit state is formulated accordingly. Simple equations are derived for shear strength verification and for designing transverse reinforcement. The method is validated by comparing its predictions with the results of 1131 shear tests, obtaining very good results in terms of mean value and coefficient of variation. Because of its accuracy, simplicity and theoretical consistency, the proposed method is considered to be very useful for the practical design and assessment of concrete structures subjected to combined shear and bending.Peer ReviewedPostprint (published version

Highlights:8  Experimental studies on fatigue and monotonic tests with corroded an uncorroded steel

Fifty percent of the total weight of construction and demolition waste is concrete. Consequently, the utilisation of crushed waste concrete must be considered as imperative in concrete production. Recycled aggregates are formed basically by adhered mortar and original aggregates. Adhered mortar is a very porous material, with a high absorption capacity and high permeability. Four different percentages (0, 25, 50 and 100%) of wet recycled coarse aggregates were used in the production of the concrete tested, the same compressive strength being obtained in all four mixes. The microstructure of recycled aggregate concrete was analysed using a fluorescent light optical microscope, which made it possible to observe the high porosity of recycled aggregates with and without adhered mortar, the increment of air void percentage in new cement paste when high amounts of recycled aggregates are used and the effectiveness of new interfacial transition zone in recycled aggregate concrete.