This paper presents research results of composite tubes filled with self-compacting concrete. The impact of the selected materials and geometric factors on resistance to the vertical shear was evaluated in this study. The resistance of the tested members was compared with recommendations given in Eurocode PN-EN 1994-1-1. From the results obtained in the tests it can be deduced that more parameters should be taken into consideration when determining resistance to the vertical shear in the interface between steel and concrete than PN-EN 1994-1-1 recommends.
Light-weight Self-Compacting Concrete (LWSCC) might be the answer to the increasing construction requirements of slenderer and more heavily reinforced structural elements. However there are limited studies to prove its ability in real construction projects. In conjunction with the traditional methods, artificial intelligent based modeling methods have been applied to simulate the non-linear and complex behavior of concrete in the recent years. Twenty one laboratory experimental investigations on the mechanical properties of LWSCC; published in recent 12 years have been analyzed in this study. The collected information is used to investigate the relationship between compressive strength, elasticity modulus and splitting tensile strength in LWSCC. Analytically proposed model in ANFIS is verified by multi factor linear regression analysis. Comparing the estimated results, ANFIS analysis gives more compatible results and is preferred to estimate the properties of LWSCC.
The ductility of High Performance Concrete (HPC) can develop both in tension and compression.This aspect is evidenced in the present paper by measuring the mechanical response of normalvibrated concrete (NC), self-compacting concrete (SC) and some HPCs cylindrical specimensunder uniaxial and triaxial compression. The post-peak behaviour of these specimens is definedby a non-dimensional function that relates the inelastic displacement and the relative stress duringsoftening. Both for NC and SC, the increase of the fracture toughness with the confinement stressis observed. Conversely, all the tested HPCs, even in absence of confinement, show practically thesame ductility measured in normal and self-compacting concretes with a confining pressure. Thus,the presence of HPC in compressed columns is itself sufficient to create a sort of active distributedconfinement.
The rheological properties of self-compacting concrete are closely influenced by temperature and the time. Previous studies which aim was to research the effect of temperature on self-compacting concrete workability, showed that the behaviour of fresh SCC at varying temperatures differs from that of normal vibrated concrete. The paper presents the study of rheological properties of fresh self-compacting concrete mixtures made with portland, blast furnace and component cement. Two types of superplasticizers were used. It was proven that temperature has a clear effect on workability; it can be reduced by selecting the appropriate superplasticizer and cement.