The formation of steel–concrete composites using individual steel and concrete elements is commonly ensured by two different connection techniques at connected interface level: mechanical connectors and structural adhesives. Among these two connection techniques, the use of structural adhesive for bonding steel and concrete elements is rapidly increasing; primarily owing to uniform transfer of stresses over the entire bonded area. The behaviour of bonded connection with change in adhesive bond layer thickness at the level of composite interface are analysed using finite element analysis under static loading to examine the ultimate strength and shear stresses. The failure governing parameters of bonded connections, such as engendered stresses in terms of von-mises and hydrostatic stresses at bearing ends of the composite interface along with changes in failure patterns (from adhesive to cohesive) are discussed. Also, the maximum engendered stresses along the failure plane for different bond layer thicknesses are examined. In case of one mm bond layer thickness the variation in shear stresses is very high along (39.28 MPa to 23.15 MPa) and perpendicular (34.62 MPa to 16.97 MPa) to the loading direction. While, the specimen with three mm thickness exhibits maximum load bearing capacity, it also has relatively smaller variation in shear stresses along (34.91 MPa to 21.72 MPa) and perpendicular (32.72 MPa to 17.20 MPa), which shows uniformity of stresses with increase in thickness. However, a further increase in the thickness of the bond layer results in reduction in the shear capacity of the specimen.

This research provides insight of experimental study on performance of concrete produced from natural and recycled aggregates. The strength of recycled aggregate concrete and its durability is still questionable as compared to the concrete with natural aggregates. The intention of this research was to assess the longevity and durability of concrete specimens composed of both conventional and recycled aggregates. This experiment involved preparing concrete specimens with recycled aggregate at 0%, 50% and 100% using a M25 mix design. The physical and mechanical characteristics of the concrete specimens such as compressive test, UPV test and split tensile strength test were assessed over a period of 28 days. The water absorption is very crucial as it can lead to concrete degradation and reduced durability over time. The results of this study indicate that strength of concrete using recycled aggregates along with silica fume and metakaolin shows enhanced mechanical properties. Therefore, recycled aggregates may be a viable and ecologically acceptable and substitute to natural aggregates in the preparation of concrete.

Development of concrete as a construction material is most extensively used, around the world, leading to its inadvertent over exploitation. The extraction of the natural constituents of concrete, namely gravel and sand has a huge environmental impact. The insatiable demand for infrastructural development has led to the exploration of alternate constituents of concrete. The foundry industry waste can be a promising alternative to natural sand in concrete. In this article, the effectiveness of foundry sand, which is a byproduct of ferrous and non-ferrous metal casting industries having high silica content has been explored as a replacement for sand. The presence of silica in waste sand obtained from foundry draws attention towards its use in civil engineering applications such as partial replacement or full replacement of fine aggregate in production of concrete. Many studies have been performed on the use of waste foundry sand in concrete and concrete related items such as replacement of aggregate (fine), and bricks, blocks, and paving stones. The current study provides an idea about the scope of waste foundry sand utilization. It also yields the modification in physical, mechanical, microstructural, and durability properties of concrete.

Fibre composites are nowadays being used in various engineering applications to increase the strength and optimize the weight and the cost of the product .The use of composite material field is increasing gradually in Engineering .Because of the expanding natural concerns bio composites produced out of the natural fibre and resin is one of the late advancement in business and constituent the present extent of natural work. In our project an investigation will be carried out to make better utilization of banana fibre for making value added products. A Specimen is fabricated by hybridisation of Natural fibres (Banana Fibre and Jute Fibre) and epoxy resin. Another Specimen is fabricated by hybridisation of Fibre (Banana Fibre, Jute Fibre, and Carbon Fibre) and epoxy Resin. Experiments are carried out as per American Standard of Testing and Materials (ASTM) standards to find the mechanical Properties of both specimens. The accessibility of characteristic fibre and simplicity of assembling have enticed scientists worldwide to attempt by regional standards accessible inexpensive fibre and to learning their achievability of fortification determination and to what degree they fulfil the obliged particular of great strengthened polymer composite aimed at structural requisition. The effect of fibre loading and length on mechanical properties like tensile strength and flexural strength of composites is studied

The performance of steel-concrete composite structural members depends on the connection at the steel-concrete interface. Structural adhesives are gaining rapid recognition as the bonding material between steel and concrete interfaces. The thickness of adhesive layer in a composite connection plays a key role in maximising the bond capacity. In this paper, the effect of the change in thickness of adhesive layer on the capacity of connection, ultimate slip at the interface, and the shear stiffness of connection have been studied. Twenty-five test specimens were cast and tested under direct shear to achieve the optimum thickness of adhesive layer. The ultimate strength and relative slip of all five adhesive layer thicknesses of steel-concrete specimens, obtained through experimental studies, were verified using finite element analysis. The failure patterns of bonded connection were also critically observed and found to be varying with adhesive layer thickness. It changes from adhesive failure to mixed (adhesive and cohesive) failure, and from mixed failure to cohesive mode of failure, with increasing thickness. At the optimum thickness, the composite interface experiences a mixed mode of failure. The effectiveness of bonded connections over mechanical shear stud connections was outlined through a comparison of the load-slip behaviour of both.

The effectiveness of a composite connection lies in the adequate transfer of forces between the steel and concrete elements. The connection strategy adopted, determines the behavior of connection. This behavior of composite specimens connected using headed studs depends on various factors, such as, cross-sectional area and dimensions of shear connectors, material properties of connectors, grade of concrete, type of loads acting on the members and quantity and location of reinforcement in concrete slab. Current study addresses the effects of confinement of concrete by altering the quantity and location of reinforcement on composite connection. The behavior of connection was investigated in terms of connection bearing capacity, ductility and shear stiffness from load-slip curve. The shear stiffnesses of composite specimens were estimated through bilinear idealization of the obtained load-slip curves using energy balancing approach. The stiffness, strength and ductility of composite connections were found to increase with an increase in the percentage of reinforcement in the concrete layer. The distance between root of stud and first layer of reinforcement was found to be inversely related to strength and stiffness and directly related to ductility.

This paper chronicles the use of structural adhesives in civil engineering construction since its inception. The usage of structural adhesives as effective and popular strengthening agents has been discussed. The application of structural adhesives as connecting agents, especially in cases of steel–concrete composites has also been discussed in detail. Various factors influence the bond strength of interfaces, such as the physical, mechanical and chemical properties of structural adhesives and adherends, the shape of adherends, water immersion, adhesive layer thickness, bonded area geometry, relative humidity and temperature of the environment during curing and service life, the amount and type of fillers and surface finishing of adherends.

The aim of the study was to observe and provide a qualitative comparison of the behaviour of mechanically connected and adhesively bonded steel-concrete composite connections under impact load. For this, steel-concrete composites connections were subjected to drop-weight impact test. The number of blows required for crack initiation and final failure (serviceability failure in case of the stud connection) were noticed. It was found that the adhesively bonded connection can resist comparatively higher number (twice) of blows for crack initiation but, the number of blows required for final failure were relatively less. The adhesively bonded connection showed a brittle failure in concrete near the adhesive concrete interface whereas the mechanically connected specimen showed ductile failure due to concrete crushing in composite specimen nearby the studs.