Papers by Keyword: Recycled Aggregate Concrete (RAC)

Abstract: Three full-scale reinforced supported beams with different recycled coarse aggregate percentage were researched and compared in order to research their structural responses under different temperature. This paper investigated the impacts of recycled coarse aggregate on the strain of concrete, deformation and the bearing strength of specimen. The experiments show that the flat section assumption is available for RAC components. Besides, the failure force of RAC components is slightly poorer than that of NAC component. By analyzing a large number of studies, the predictions of bending failure strength and deformation of RAC specimen according to the code for design concrete structures (CDCS) are compared with the experimental results. Besides, the bending performances under room temperature and fire were compared.

Abstract: This article mainly research on different replacement rate of recycled concrete at home and abroad are summarized , and expounds the various researchers in the research of recycled concrete. Outlines the basic properties of recycled concrete, and explain the effects of replacement ratio of recycled concrete, for the development and application of recycled concrete are proposed.

Abstract: As an eco-material, the application of recycled aggregate concrete and rapid repair concrete has been deeply researched in recent years. But the application of recycled aggregate concrete with recycled fine aggregate and recycled powder in pavement rapid repair project is seldom. Combing with the related literatures and our own engineering practice, the state-of-the-art report of recycled aggregate concrete and rapid repair concrete is presented, and hope to supply a new way to solve the long-standing issue of waste cement concrete recycling and rapid opening traffic simultaneously.

Abstract: Chloride ion penetrability of recycled aggregate concrete is one of durability, but it is less on research at present. It simulates resist function which recycled aggregate concrete exists in chlorine ion environment, Results on comparing with natural aggregate concrete will provide reference to study on durability of recycled aggregate concrete.

Abstract: Construction waste has been increasing due to fast development of construction industries. These wastes usually end up on landfill or to be left nearby construction site. This paper focuses on the potential use of recycled waste aggregate in a development of reinforced concrete rectangular container, RACC, as a solid waste storage. The filled container is intended to be used as a retaining structure at riverbanks to control erosion. The experimental programme include cube and cylindrical specimens tested to determine characteristic properties of recycle aggregate concrete (Pc, Pt, E). The characteristic properties obtained were used in designing the RACC to function as storage container and also as a retaining wall as referred to BS 8110 and BS 8007. Results showed that recycle aggregate concrete has relatively high compressive strength, tensile strength and modulus of elasticity. RACC size of 1.0 m x 1.0 m x 1.0 m with 150 mm thickness is found to be suitable and safe to be used both as container and retaining wall. This is proven by the maximum deflection and crack widths achieved which are lower than the allowable limit values.

Abstract: In view of the importance of recycled aggregates concrete with primary aim to minimise environmental impacts from construction waste, this study was conducted in order to investigate the effects of recycled aggregates on concrete elastic modulus. The outcomes indicate that type of recycled aggregates influences the development of concrete elastic modulus. In general, the use of recycled aggregates posts significant reductions in concrete elastic modulus.

Abstract: Microstructure is an important factor that influences the mechanical properties of recycled aggregate concrete (RAC). This paper was devoted to an investigation of the relationship between mechanical properties and porosity, hydrate, microstructure of interfacial transition zone (ITZ) in RAC. The result showed that mechanical properties of RAC can be further enhanced with lower porosity, and there was a good linear relation, whereas it did not exist between compressive strength of RAC and average pore diameter. Fine active particles and the hydrate were formed into the cracked and loose layer of ITZ in RAC by A tripe mixing method (TM). Through SEM observation, it is expected that the compressive strength of the RAC can be improved by modifying the porous microstructure and hydrate in ITZ.

Abstract: To make great use of recycled deserted solid and concrete confined by steel tube has been one of the most significant tasks for sake of green low-carbon production and environmental-friendly sustainable development, especially now, as the earthquakes in recent years have resulted in a host of deserted solids and concrete wastes. Engineering application of recycled-aggregate-concrete-filled (RAC-filled) steel tube is a new challenge facing humanity. Force of Steel tube components in practical engineering application is nonlinear and random. Owing to the difficulty in conventional method, it becomes a main subject to reveal the nonuniform axial force mechanisms of steel tube components. First of all, this article adopts finite element method (FEM) to simulate actual force, to analyze mechanics of axial force of steel tube components under uniform, nonuniform and eccentric conditions, thus building a mechanical model. Then the effect on the load capacity of steel tube caused by local factors such as steel tube components under different force conditions and deformation in the process of steel tube production is analyzed. Finally, the three force simulations of circular steel tube components in the diameter of 165mm, a wall thickness of 4mm and 2mm are carried out separately, it turns out that the error of component with a thickness of 2mm is 4.96% while the other is 7.35%. Obviously the simulation and experimental results fit relatively well. Besides, eccentric load is related to eccentricity: the larger the eccentricity is, the smaller the load capacity is. Moreover, it needs to be singled out that nonuniform capacity is greater than centralized eccentric axial load capacity. The research results demonstrate that different parameter selection,different force and manufacturing precision of steel tube and its component exert relatively high influence on load capacity of component. The results also indicate that variety of force conditions and deformation has to be considered in applications of RAC-filled steel tube. Thus, the research provides reference and basis for RAC-filled steel structure design and manufacturing.

Abstract: In modern society, the development of urbanization process makes the increasing waste concrete and natural aggregate resource increasingly drying up. Recycled concrete research has become the inevitable development of society. This paper briefly introduces the research status of waste concrete recycling, and points out the current waste engineering application research status and existing problems of the concrete utilization. The industrialization of recycled concrete is in accordance with the needs of environmental protection and sustainable development strategy.

Abstract: Based on the ever finished investigations of physical and mechanical properties of recycled aggregate concrete (RAC), and a series of experimental studies on the durability, the fatigue behavior, mechanical behavior and the seismic behavior of RAC components. A full scale model of a one-storey block masonry structure with tie column + ring beam + cast-in-place slab system and a one fourth scaled model of a 6-storey frame structure, which are made of reinforced recycled aggregate concrete, are tested on a shaking table by subjecting it to a series of simulated seismic ground motions, and the seismic behaviors of the RAC structures were experimentally investigated. The dynamic characteristics and the seismic response were analyzed and discussed. The overall seismic performance of RCA structures are evaluated, the analysis results show that the recycled aggregate concrete structures with proper design exhibits good seismic behavior and can resist the earthquake attacks under different earthquake levels in this study. It is feasible to apply and popularize the RAC block masonry buildings less than 2 stories and the RAC frame buildings less than 6 stories in the region where the seismic fortification intensity is 8.