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Performance and Service Life of Self-Compacting Concrete
Published in Ganesh Babu Kodeboyina, High Performance Self-Consolidating Cementitious Composites, 2018
Roziere (2007) studied different concretes with paste volume, water content, and limestone powder content variations through shrinkage and fracture characteristics of these SCCs. The restrained shrinkage ring test was used for characterizing the shrinkage effects on the fracture effects of measured-through beam specimens of 100 × 150 × 700 mm. The fracture behavior is characterized through fracture toughness and crack tip opening displacement (CTOD) values. Acoustic emission maps of the fracture specimens were also attempted. It was seen that water content has a more significant effect than pace content on the strength and elastic modulus of these concretes. Li (2011) studied concrete of the joint section between steel and concrete of the box girders of the hybrid cable-stayed bridge across the Yangtze River. The high-strength SCC was made with 55 grade cement containing both steel and polypropylene fibers. The concretes achieved a strength of about 70–80 MPa. The split tensile and elastic moduli of these concretes were also studied. The fracture toughness characteristics of I5, I10, and I30 for these concretes along with the plastic shrinkage cracking and creep were measured. The chloride-ion permeability values of the 28-day concrete were observed to be less than 4.0 × 10−12 m2/s. The freeze–thaw resistance showed that the relative dynamic modulus of elasticity was more than 60% after 200 cycles.
Applications to Fracture Mechanics
Published in Abdel-Rahman Ragab, Salah Eldin Bayoumi, Engineering Solid Mechanics, 2018
Abdel-Rahman Ragab, Salah Eldin Bayoumi
Examination of fractured test specimens indicated that crack faces have moved apart and initially sharp crack has been blunted by plastic deformation. Both crack-face movement and blunting have been increasingly proportional to the material toughness. This has led the proposal to use crack tip opening displacement (CTOD) as a measure of fracture toughness, especially for conditions where considerable plasticity occurs in the vicinity of the crack tip.43 This is based on relating CTOD to the stress intensity factor in the case of small-scale yielding, i.e., LEFM, or to the J-integral for conditions of EPFM.
Influence of different stirring speed on fracture properties of wedge splitting specimens
Published in Mechanics of Advanced Materials and Structures, 2022
All the tests are carried out on a 300 t hydraulic testing machine and the 8-channel IMC acquisition system is adopted to collect data. In the meantime, the clamp extensometer, ranging from 0 to 4 mm is utilized to perform measurement on the crack opening displacement (CMOD) and crack tip opening displacement CTOD. A 5 t load sensor is used to measure the vertical load of the specimen. A resistance strain gauge is arranged at the crack tip to monitor the crack initiation. The displacement loading method is adopted in the test and takes about 30-60 minutes for the process to be completed. Furthermore, the stiffness of the testing machine meets the requirements, and the complete descending section of the loading process is obtained.