This research involved the design of 18 sets of recycled concrete mixture. Table 2 details the exact mix designs, including water-cement ratios of 0.48, 0.53, and 0.59 and the substitution rate of RA for NA ranges from 0 to . Polycarboxylic superplasticizer was utilized to regulate the slump of the fresh concrete mix, ensuring it …

(For example, RAC-100: recycled coarse aggregate concrete with a 100 % replacement ratio.) 2.3.4. SEM test. The micromorphology of the old mortar and the new mortar was analyzed by SEM. The equipment used was a Quanta 600 FEG with a resolution of 1 nm and magnification of 100 to 400,000 times. SEM samples were …

Choose P.O 42.5 grade Portland cement. Sand is general natural sand with fineness modulus of 2.6, particle size range of 0 ∼ 4.75 mm. The coarse aggregate with a particle size of 5 ∼ 20 mm (see Fig. 1 ce:float-anchor refid="fig2"/>). Recycled coarse aggregate comes from the abandoned test wall of the structural laboratory of Shenyang …

Freeze–thaw cycles and steel reinforcement corrosion can damage the properties of concrete structures in a frigid marine environment. In this paper, experimental and analytical research on the …

This construction waste could be reused as recycled coarse aggregate . Compared with natural aggregate, recycled aggregate has sharper edges, rougher surface, higher water absorption, and lower density, which will affect the strength characteristics of concrete . Furthermore, with the rapid development of the lithium salt …

The research on chloride corrosion resistance of recycled coarse aggregate concrete modified by graphite tailings (GTRAC) is in its early stages and has significant potential for improvement in the areas of microscopic mechanism, key influencing factors, mathematical theoretical models, and numerical evaluation. This interdisciplinary study ...

The RCA used in this test was obtained from waste pavement concrete by crushing and processing, followed by the screening process. In this test, the RCA was continuously graded from 5 to 20 mm, where 5 to 10 mm RCA was mixed with 10 to 20 mm RCA in a ratio of 1:2, and the aggregate morphology is shown in Fig. 1.The apparent …

The RCA is composed of coarse recycled concrete aggregate (CRCA) and fine recycled concrete aggregate (FRCA). The CRCA is a small concrete component made up of old coarse aggregate, mortar, and interfacial transition zone (ITZ), whereas the FRCA (>5 mm) is made up of crushed and sieved waste concrete mortar fragments.

Recycled coarse aggregate (RCA) made from waste concrete is not a suitable structural material as it has high absorption of cement mortar, which adheres on the aggregate surface and on the tiny cracks thereon. Therefore, when using RCA made from waste concrete, much water must be added with the concrete, and slump loss …

The chloride profiles and transport characteristics of carbonated recycled coarse aggregate concrete (CRCAC), recycled coarse aggregate concrete (RCAC), and natural coarse aggregate concrete (NCAC) were analysed and compared. The results indicated that the chloride penetration depths and concentrations of CRCAC were …

Great efforts are made to utilize waste in the construction industry for many different reasons, including the limited non-renewable sources of concrete constituents and getting rid of the burdens of deploying waste and its environmental impact. This study aims to assess the suitability of using recycled coarse aggregate (RCA) and plastic waste …

The results show that as the polypropylene fiber content increases, the direct shear stress of concrete (Natural aggregate concrete and recycled coarse aggregate concrete [RCA]) first increases and then decreases gradually. Meanwhile, the best PP fiber content is 0.9 kg/m 3 in this study. Furthermore, the compression …

Materials used for the development of recycled aggregate concrete are: 1) Ordinary Portland cement 53 grade, 2) river sand conforming to Zone II as fine aggregate 3) Coarse aggregate sizes of 10 mm and 20 mm are mixed in the ratio of 40:60 by mass of total coarse aggregate and 4) water-cement ratio of 0.55.

Recycled Concrete Aggregates: A Review. Katrina McNeil. 1), and Thomas H.-K. Kang. 2), *. (Received December 30, 2012, Accepted January 27, 2013) Abstract: This paper discusses the properties of ...

This paper presents guidelines for using recycled-concrete aggregate (RCA) as a full or partial replacement for natural coarse aggregate in new concrete (RCA concrete). Several international standards and guidelines for the use of RCA in concrete are reviewed and contrasted to identify areas in which further development is required.

Gravels constitute the majority of coarse aggregate used in concrete with crushed stone making up most of the remainder. Natural gravel and sand are usually dug or dredged from a pit, river, lake, or seabed. Crushed aggregate is produced by crushing quarry rock, boulders, cobbles, or large-size gravel. Recycled concrete is a viable source of ...

This study intends to propose a new model for estimating the autogenous shrinkage of recycled aggregate concrete (RAC) with recycled coarse aggregate (RCA). To this end, two groups of RCAs were selected to prepare RAC samples with different RCA substitution levels and water-to-cement (w/c) ratios. The autogenous shrinkage was …

Also recycled fine aggregate (RA1) and recycled coarse aggregate (RA2) are used as RA in the concrete mixtures. For this purpose, twelve concrete mixtures in three groups are produced, and the mechanical properties such as the compressive strength, the tensile splitting strength, elasticity modulus, physical properties such as …

Recycled coarse aggregate concrete (RCAC) can be made by replacing natural coarse aggregate (NCA) with RCA [5]. The global protection of the environment is growing. RCAC is a green building material, which conforms to the sustainable development strategy of carbon peaking and carbon neutrality goals. In recent years, the research on …

The slump test is the common and practical workability test for fresh concrete and is performed in accordance with ASTM C143 [17]. Fig. 1 shows the slump values for HPCs that are prepared with natural aggregate (b) and RA (c). The maximum detected slump value of HPC without RA was 185 mm [18].Previous studies, however, had …

the recycled aggregate. The use of recycled aggregate generally increases the drying shrinkage creep & porosity to water & decreases the compression strength of concrete compared to that of natural aggregate concrete. It is nearly 10-30% as per replacement of aggregate. Recycling reduces the cost (LCC) by about 34-41% & CO 2 emission (LCCO 2

In the present investigation, an attempt was made to study the influence of the strength of parent concrete on the properties of recycled aggregates and recycled aggregate concrete. In this study, four grades of normal concrete mixes: M20, M25, M30, and M40 were considered as parent concrete to produce the recycled coarse …

Recycled coarse aggregate (RCA) is the most common idea, but it does not gain wide acceptance among practitioners due the adhered mortar poses which deleterious effects on the concrete. However, a suitable concrete mix design enables the recycled aggregate concrete (RAC) to the achieve target strength and suitable for wide range of …

Recycling of concrete is a simple process. It involves breaking, removing, and crushing existing concrete into a material with a specified size and quality. As per study about 75 to 80% of total construction material consist coarse aggregate portion. When the structure is demolished, the waste concrete in a large quantity is produced.

high strength concrete with recycled coarse aggregate of partial replacement for conventional coarse aggregate. The tests conducted are Split Tensile Strength and Flexural Strength of concrete by replacing coarse aggregate at different percentages by 0%, 10%, 20%, 30% 40%, 50% by weight and the mixes are test for a period of 7

These included four different RCA replacement levels (0%, 30%, 50% and by weight of the natural coarse aggregate) and two different cementitious systems (plain system – Type I portland ...

Plain Portland cement P.O 42.5R is used in the test, which meets the Chinese standard for common Portland cement (GB175-2007), and its mineral components are presented in Table 2.Natural river sand with a nominal maximum size of 4.75 mm is used as the fine aggregate, which has an apparent density of 2590 kg/m 3 and a …

Given that the present work primarily focuses on presenting a numerical framework with the ability to reasonably predict the fracture behavior of seawater and sea-sand mixed recycled coarse aggregate concrete despite the model's approximations such as neglecting individual aggregates and the interfacial zone between aggregate …

Abstract This study proposes a new mix design method for C30 recycled concrete using recycled aggregate crushed from different strength source concrete (SC). The dosages of cement, water, sand, and coarse recycled concrete aggregate (CRCA) are the same as the corresponding components in natural concrete, but the CRCA …

Type I ordinary Portland cement was used as a binder content for the experiment. The chemical compositions were illustrated in Table 1.River sand with the size below 5.0 mm was complied with zone 2 grading limit of the DoE design method used as fine aggregate [18].Crushed granite was used as coarse aggregate with specific …