This research aimed to investigate the mechanical and physical properties of Roller Compacted Concrete (RCC) used with Recycled Concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³,of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’, s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15. 0 MPa at 28 days, splitting tensile strength above 1. 9 MPa, flexural tensile strength above 2. 9 MPa, and modulus of elasticity above 19. 0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.

Self-consolidating concrete (SCC) is a relatively new approach to making concrete, and it is characterized by its high flowability and resistance to aggregate segregation in the plastic state. A total of 3 beams were tested in this experimental investigation on the flexural ductility of reinforced concrete beams made with self-consolidating concrete. The beams were made from concrete having average compressive strength of 30 MPa and reinforcement ratio in the range of 0.15-1.38. Three self-consolidating reinforced concrete beams with different percentage of and constant amount of were cast and incrementally loaded under bending. During the test, the strains on the concrete middle face and on the tension and compression bars as well as the deflection at different points of the span length were measured up to failure. This paper compares the ductility of reinforced beams cast with SCC concrete to the theoretical calculations based on two codes (ACI, CSA) recommended for the reinforced concrete members that vibrated into place to ensure proper filling and consolidation. Based on the results obtained, effect of increasing tension reinforcement on the curvature and displacement ductility of the self-consolidating concrete reinforced members is more deeply reviewed. Comparisons between theoretical and experimental results are also reported here. Generally, it was concluded that, self-consolidating reinforced concrete beams yielded greater ductility as opposed to the theoretical calculations based on two codes (ACI, CSA) recommended on conventional reinforced concrete beams.

In this research, we observe the effect of high strength SCC concrete on shear behavior, cracking moment & condition. The main testing parameters are concrete type, stirrups distance and concrete strength variation. Therefore nine samples were casted which three of them are normal concrete with 400 MPa strength and the others were SCC with high strength of 60 and 80 MPa. Stirrup distances of 80, 100 and 133 millimeters used for each groups. The testing beams were loaded with simple supports under two concentrate loads. The results have appeared that stiffness and ultimate shear strength increased with using SCC concrete whereas the displacement decreased. Modes of cracking and patterns of normal and high strength SCC concrete were the same in ultimate load and ductility and ultimate load is increases by stirrups distance reduction in each beams.

Fire behaviour of ordinary (traditional), dense and SCC concretes is reviewed. Concrete is usually known as a material with good fire resistance. However, the mechanical resistance of concrete reduces with rising temperature because of chemical and dimensional changes, which can result in failure of the concrete element. Concrete has considerable amounts of water, which with high thermal capacity and low thermal conductivity of concrete can result in a low heat transfer rate from hot surface to bulk of concrete and hence delay the failure of component in fire. In contradictory, these characteristics can result in producing high vapour pressure in regions near the surface and spalling of concrete, which reduces the fire resistance of element, especially when the cover of reinforcing bars fails. The risk is much higher in dense concretes, like HSC and HPC. During the expose of concrete to fire, simultaneous heat and mass transfer phenomana cause that humidity trnsfers into internal layers. The vapor pressure will be rised in a region near the surface and reached to a maximum in a distance, which depends upon heating rate, moisture content, porosity, properties of materials, environment conditions, etc. The spalling will be occurred, if tensile strength is less than this pressure. Dense concrets may suffer from spalling in conditions that is not a risk for normal concretes. Self-compacting concretes also show different behaviour from other concretes at high temperatures. This is due to different compounds and high content volume of powders. The powders may result in a consirable decrease in fire resistance of concrete, because of low thermal stability or rise of packing of system, which can cause spalling in early stages of fire.