Mechanical Properties Of Recycled Concrete Research Articles

Effect of nanosilica and fiber on mechanical properties and microstructure of recycled coarse aggregates road concrete

Recycled coarse aggregate has its own characteristics of large porosity, high water absorption and high crushing index, which adversely affects the mechanical strength and durability of recycled aggregate concrete. In this study, the mechanical properties, durability and microstructure of recycled aggregate concrete (RAC) modified with nano-SiO2 (NS) and fibres were investigated to prepare road RAC, using NS polypropylene fibres (PPF) and basalt fibres (BF) as test variables. Compared with RAC only incorporating NS, NS and fibre synergism can significantly enhance the mechanical properties of recycled concrete, compressive strength increased by 27–51 %, flexural strength increased by 12 %, and abrasion resistance increased by 25–72 %. The synergistic effect of NS and PPF significantly improves the frost resistance of recycled concrete. NS has a volcanic ash effect which can react with calcium hydroxide to produce a large number of C-S-H in the secondary hydration reaction, making the internal structure of the cement matrix denser. Interfacial transition zone microstructure is more compact, thus interfacial transition zone porosity is effectively reduced. The hydration products are attached to the fibre surface, which enhances the bonding ability between the fibers and matrix. Therefore, the fibres effectively inhibit the generation and development of internal micro-cracks. NS optimises the internal pore structure of recycled aggregate concrete and enhances the interfacial transition zone, and NS synergistically with PPF can improve the strength and durability of various mechanical properties of recycled concrete. The research results provide the scientific basis for the application of road RAC.

Mechanical Properties of Recycled Concrete with Polypropylene Fiber and Its Bonding Performance with Rebars

This paper explores the influence of polypropylene fiber on the mechanical properties of recycled concrete and the bonding performance between recycled concrete and steel bars. The results indicate that the compressive strength and splitting tensile strength of concrete decrease with the increase in the replacement rate of recycled aggregate. When the replacement rate of recycled aggregate was 100 %, the compressive strength of concrete decreased by 25.0%, while the splitting tensile strength of concrete decreased by 21.7 %. The compressive strength and splitting tensile strength of recycled aggregate concrete show a trend of first increasing and then decreasing with increasing fiber content. When the fiber content is 0.09 %, the compressive strength and tensile strength of recycled aggregate concrete are optimal. The bond strength of recycled concrete pullout specimens with fiber is higher than that of recycled concrete pullout specimens without fiber, while the slip of recycled concrete pullout specimens with fiber is lower than that of recycled concrete pullout specimens without fiber. The maximum improvement in bonding performance between recycled concrete and rebars with a 50 % recycled aggregate replacement rate is 13.7 %, and the maximum improvement in bonding performance between recycled concrete and rebars with a 100 % recycled aggregate replacement rate is 11.8 %. The bond strength shows a trend of first increasing and then decreasing with increasing fiber content, but the degree of decrease was not significant, while the slip shows a trend of first decreasing and then increasing with increasing fiber content. Compared to the compressive strength of concrete, the splitting tensile strength can better reflect the bond strength between concrete and rebar. The nonlinear relationship between the bond strength, compressive strength, and splitting tensile strength of recycled concrete is established. This study can effectively improve the mechanical properties of recycled concrete, expand the application scope of recycled concrete technology, and promote the sustainable development of the construction industry.

Experimental Study on Preparation and Characteristics of Concrete Modified by Construction Waste

With the advancement of urbanization construction, the proportion of construction waste to the total urban waste continues to increase, especially waste concrete. The treatment and reuse of waste concrete is a major trend that poses enormous pressure on environmental protection. This article focuses on the problems in the preparation of recycled aggregates from waste concrete, which has important practical value. This article presents a new type of recycled concrete prepared through surface modification of recycled coarse aggregate and design experiments to change the replacement rate of coarse aggregate. The physical properties of recycled coarse aggregate, workability of fresh concrete, and mechanical properties of recycled concrete are analyzed. The research results indicate the following: (1) Through surface modification, recycled concrete can improve the workability of fresh concrete at a fixed water cement ratio, which can meet the requirements of mixing, transportation, and pouring of fresh concrete. (2) By modifying the surface of recycled aggregates, the strong water absorption performance of recycled aggregates caused by old mortar and surface defects has been reduced. And the modification effect of recycled aggregate improves the hydration process of recycled concrete, making the surface structure dense and further enhancing the strength of recycled concrete. (3) The compressive strength of recycled concrete specifications from construction waste shows a decreasing trend with the increase in coat aggregate replacement rate. The final ratio is as follows: modular dose of 12%, modification time of 90 min, and 20% recycled aggregate content.

A Brief Review on Recycled Aggregate Concrete

This paper briefly introduces the recycling and regeneration preparation of waste concrete, as well as the crushing and screening process of waste concrete blocks. The properties of crushed aggregate and the physical and mechanical properties of recycled concrete were analyzed, and the research status of compressive strength and splitting tensile strength of waste concrete at home and abroad was summarized and analyzed. Factors such as water-glue ratio, water absorption, apparent density of recycled coarse aggregate, state of recycled coarse aggregate and strength of virgin concrete will affect the strength of recycled aggregate concrete. This paper also summarizes the relationship between the splitting tensile strength of recycled aggregate concrete and the compressive strength of the cube.

Study on the mechanical properties and microstructure of recycled brick aggregate concrete with waste fiber

Abstract Recycled concrete technology can promote the sustainable development of the construction industry, but the insufficient mechanical properties of recycled concrete have become a key constraint on its development. By adding waste fibers, the mechanical properties of recycled concrete can be improved, and the problem of disposing of waste polypropylene fibers can be solved. In this article, the effects of recycled brick aggregate content and waste fiber content on the mechanical properties and microstructures of recycled brick aggregate concrete through macroscopic mechanical experiments and microstructure experiments are investigated. The results show that the addition of recycled brick aggregate reduces the mechanical properties of concrete; when the content of recycled brick aggregate is 100%, the compressive strength and splitting tensile strength decrease by 22.04 and 20.00%, respectively. The addition of waste fibers can improve the mechanical properties of recycled brick aggregate concrete, but it is necessary to control the contents of waste fibers in a certain range. When the content of waste fibers is 0.08%, the best improvement effect on the mechanical properties of concrete is achieved; the compressive strength of concrete with a 50% (100%) recycled aggregate replacement rate increases by 6.06% (8.90%), while the splitting tensile strength of concrete with a 50% (100%) recycled aggregate replacement rate increases by 2.30% (6.16%). Through microstructural analysis, the mechanism by which waste fiber improves the mechanical properties of recycled brick aggregate concrete is revealed. The addition of waste fibers has the effect of strengthening the framework inside the recycled brick aggregate concrete, forming a good structural stress system and allowing the recycled brick aggregate concrete to continue to bear loads after cracking. In this study, waste brick aggregate and waste fiber are effectively utilized, which can not only reduce pollution to the environment but also realize the sustainable utilization of resources.

Study on the preparation and mechanical and fatigue properties of alkali excited recycled concrete

This study aims to explore the preparation process of alkali excited recycled concrete, and evaluate its performance in terms of mechanical and fatigue properties, so as to provide theoretical and practical support for the application of sustainable development and environmental protection building materials. Laboratory test and performance evaluation were used to prepare alkali-stimulated recycled concrete specimens with different proportions by adjusting fly ash, alkali activator and water solid ratio in recycled concrete. Then, the mechanical properties of the specimen were tested, including the influence of the cementing material on its compressive strength and the influence of the aggregate quality on its compressive strength. Finally, the fatigue life test is used to analyze the fatigue performance of alkali stimulated recycled concrete, and the influence of different ages and different stress levels on fatigue damage performance of alkali stimulated recycled concrete specimens is studied. The experimental results show that the mechanical properties of recycled concrete can be significantly improved by using alkali excited recycled concrete preparation technology. It is found that under the same stress ratio, with the increase of age, the corresponding fatigue life will increase, the flexural tensile strength will increase, and the fatigue resistance will improve. At the same age, the fatigue life of specimens decreases with the increase of stress ratio, and the flexural tensile strength and fatigue resistance remain unchanged. This study proves the effectiveness of alkali excited recycled concrete preparation technology in improving the mechanical properties and fatigue properties of recycled concrete. Alkali stimulated recycled concrete is not only conducive to resource reuse, reduce the impact of waste on the environment, but also provides a new choice for the sustainable development of building materials. However, further research and application are needed to promote the widespread application of alkali excited recycled concrete in engineering practice.

A review of the mechanical properties and durability of basalt fiber recycled concrete

Basalt fiber (BF) is an emerging environmentally-friendly fiber. Adding basalt fiber can improve the deficient recycled concrete's poor mechanical properties and durability. By reviewing nearly 120 related papers, the effects of variables such as BF content and length (0–1.5%, 9–18 mm), recycled aggregate substitution rate (0–100%), and cement mix ratio (w/b, 0.25–0.45) on the mechanical and durability properties of basalt fiber-reinforced recycled concrete (BFRAC) were discussed. Due to the presence of vulnerable interfacial transition zones, the mechanical properties of recycled concrete (RAC) continuously deteriorate over time. However, by adding an appropriate amount of basalt fiber, it is possible to improve these structural defects by forming a network structure that enhances cracking resistance within the matrix and improves interface bonding strength among other benefits. Consequently, this significantly improves the overall mechanical properties of RAC. Additionally, while incorporating recycled aggregate (RA) may reduce compressive strength initially, this deficiency can be mitigated through the proper inclusion of fibers in RAC mixtures. Optimal compressive strength for RAC is achieved with a replacement ratio between 25–50% and a fiber content ranging from 0.2–0.3%. Furthermore, properly incorporating fibers into RAC greatly enhances splitting tensile strength and flexural strength as well; specifically achieving optimal splitting tensile strength with a replacement ratio between 40%− 50%, a fiber content at 0.3%, and utilizing fibers with lengths measuring approximately 12 mm long. The primary cause for poor frost resistance in RAC lies within numerous micro-cracks and pores present in RA aggregates which lead to high water absorption rates ultimately reaching critical water saturation points resulting in freeze-thaw damage occurrences during exposure to freezing conditions. When exposed to sulfate attack, RAC undergoes a chemical reaction with sulfate ions present in the concrete, leading to the formation of numerous expansion products that negatively impact concrete performance. Progressive dehydration of hydration products under high-temperature conditions leads to a porous structure within the concrete matrix. Incorporating fibers can impede microcrack expansion during freeze-thaw, sulfate attack, and high-temperature environments, thus enhancing the erosion resistance of RAC. Compared to conventional concrete, interfacial bonding in RAC is less tight and more vulnerable to damage in complex environments. Current research on RAC suggests that the mechanism behind its damage under complex freeze-thaw load coupling environments remains unclear. It is recommended that future studies combine large-scale component tests with computational simulations to address this issue.

Study on the modification mechanism of recycled brick-concrete aggregate concrete based on water glass solution immersion method

Recycling construction waste into concrete through the process of crushing and screening is a vital method of resource conservation. Recycled aggregates often contain imperfections such as micro-cracks, necessitating modification to produce high-performance concrete. Water glass, an economical modifier, addresses this need. However, recycled aggregates often contain concrete and brick aggregates and are difficult to completely separate. At present, there are few studies on the modification of recycled brick aggregates, and there is a lack of comprehensive and systematic research from the aggregate modification mechanism to the macroscopic working performance and mechanical properties of recycled concrete. Based on the above problems, the modification effect and modification mechanism of water glass solution on recycled brick aggregate and recycled concrete aggregate were studied by basic physical properties, SEM, and XRD tests. The relationship between macroscopic mechanical properties and the microstructure of modified recycled brick-concrete aggregate concrete was studied by compressive, flexural, and splitting tensile tests, XRD, NMR, and SEM. The results showed: (1) The best modification scheme for recycled brick aggregate and recycled concrete aggregate is the concentration of water glass solution at 4 % with a soaking time of 5 h; (2) the mechanical properties of recycled brick-concrete aggregate concrete are the best when the brick-concrete ratio is 5:5, and the compressive strength, flexural strength, and splitting tensile strength are increased by 10.84 %, 11.61 %, and 15.08 %, respectively; and (3) the water glass solution improved the pore structure and interfacial transition zone of recycled aggregate. The proportion of harmless pores and less harmful pores increased by 5.66 % and 13.3 %, respectively, and the proportion of harmful pores and more harmful pores decreased by 6.25 % and 12.7 %, respectively. The research results can promote the resource utilization of construction waste.

Effects of recycled micro-powders mixing methods on the properties of recycled concrete

Recycled micro-powders were introduced into recycled concrete by adhering them to the surface of recycled aggregate, and a systematic comparison was conducted with recycled concrete prepared with the recycled micro-powder admixture to examine the effects of the mixing modes of recycled micro-powders on the workability and mechanical properties of recycled concrete. In addition, the microhardness test, the hydration products, and the hydrated microstructure were used to investigate its mechanism. The results indicated that recycled micro-powders as a cement admixture decreased the fluidity and compressive strength of recycled concrete. However, the incorporation of recycled micro-powders attached to recycled aggregates improved the fluidity of recycled concrete and obtained a higher compressive strength; in particular, the 28d and 56d compressive strengths increased by 3.66 % and 7.28 %, respectively, compared to those of ordinary recycled concrete. When the incorporation amounts of recycled micro-powders into recycled concrete were identical, the recycled concrete exhibited a denser microstructure and higher microhardness in the interface transition zone when the recycled micro-powders were adhered to the recycled aggregate.

Experimental investigation on the seismic behavior of TRAC frame column with RCA treated by the silica fume cement paste

AbstractThe physical properties of recycled coarse aggregate (RCA) can be strengthened by pre‐soaking them in silica fume cement paste, thereby improving the mechanical properties of recycled concrete. To evaluate whether treated recycled coarse aggregate (TRCA), which is obtained by pre‐soaking in silica fume cement paste, can be applied to structural elements, considering the axial compression ratio and volumetric stirrup ratio, TRCA concrete (TRAC) frame column specimens and natural aggregate concrete (NAC) column specimens were prepared. Subsequently, a cyclic loading test was conducted on the specimens. The failure mode, hysteresis loop, skeleton curve, ductility, and energy dissipation capacity of the specimens were analyzed and compared. The results showed that compared with NAC specimens, the bearing capacities of the TRAC specimens were slightly higher. The seismic behavior of the TRAC frame columns achieved performance level similar to that of the NAC structural members at low axial compression ratios. This indicates that the RCA treatment of pre‐soaking in silica fume cement paste is effective, and TRAC can be used as loading‐bearing structural concrete.

EVA/KH560 synergistically modified recycled concrete mechanical properties - Experiment and molecular dynamics simulations

Considering the long-term working performance of recycled concrete (RC) members, there is a need to compensate for the performance deficiencies of RC. In this study, the mechanical properties of RC were improved by two different modification methods, and the reinforcement effects of RC modified by Silane Coupling Agent (KH560)/Ethylene vinyl acetate copolymer (EVA) and RC modified by EVA alone were compared and analyzed. The effects of separate modification and co-modification on RC were analyzed through multi-scale methods in terms of macro-mechanical properties, microstructure, chemical composition and molecular mechanism, respectively. The results of macroscopic mechanical experiments showed that the compressive and shear strength of EVA/KH560 synergistic modification is higher than that of EVA alone. Scanning Electron Microscope (SEM) data showed that the surface density of the old and new concrete interfaces was higher under EVA/KH560 co-modification. X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) data showed that more cement gel will be produced under EVA/KH560 synergistic modification. Molecular dynamics (MD) simulations show that EVA single modification can produce hydrogen and ionic bonds at the interface of old and new concrete, while EVA/KH560 synergistic modification not only produces them, but also forms a stable Si-O-Si chemical bond.

Analysis on the mechanical properties of recycled concrete

Recycled concrete consists of cement, water and aggregates as conventional concrete; however, the difference is that the former includes a certain percentage of recycled aggregates to achieve environmental friendliness and economic efficiency. This article would focus on the existed application of recycled coarse (RCA) and fine (RFA) aggregate in concrete manufacturing and observe the material properties, such as compressive strength, shear strength, and slump value with different proportion of recycled aggregate mixed during fabrication. Based on sample results from existed experiments, for different amount of recycled coarse aggregate applied for concrete making, the material property would be varied and the appropriate amount of recycled coarse aggregate applied is around 50% for aggregate proportion (could be different for different type of RCA applied). In RFA section, two main resources of RFA are introduced, which are the wasted bricks and concrete. By investigating related research articles, the conclusion of wasted concrete is better than wasted bricks in making RFA is obtained. Several researches are included in RFA replacement experiments, and the conclusion of RFA replacement is that the proportion should be less than 20% in fine aggregate part. Also, intermediate materials such as fly ash, slag powder and silica fume should be applied to guarantee the cohesive property of concrete product. This article illustrates the hurdles and benefits of recycled aggregate application in current stage, and the prospects of recycled aggregates application in concrete products can be more predictable by analyzing the available experiments

Effect of nano-SiO2 modified recycled coarse aggregate on the mechanical properties of recycled concrete

Improving the performance of the interface between old mortar and recycled coarse aggregate (RCA) is a hot topic and important to enhance the properties of recycled aggregate concrete (RAC). In this paper, the RCA was soaked by nano-SiO2 (NS-RCA) then the water absorption and crushing index of NS-RCA were investigated. The mechanical properties, such as compressive strength, flexural strength, and elastic modulus of RAC prepared by NS-RCA (NS-RAC) were studied. The Thermogravimetric and Differential Thermal Analysis (TG-DTA) and scanning electron microscopy (SEM) were applied to analyze the properties of the interface transition zone (ITZ) around unmodified RAC and NS-RAC. A modified stress–strain model of NS-RAC was proposed considering the concentration of nano-SiO2 and soaking time. The testing results showed that the concentration of nano-SiO2 and soaking time had significant effects on the strength and durability of RCA and the mechanical properties of RAC. The 2% concentration of nano-SiO2 and 48 h soaking time had the best modification effect on RCA. The compressive strength, flexural strength, and elastic modulus of NS-RAC with best modification were 31.8%, 33.2%, and 89.6% higher than those of unmodified RAC respectively. The TG-DTA and SEM analyses indicated that NS-RAC had the denser microstructure of ITZ. This study is conducive to enrich the knowledge about using NS-RAC and supplying guidance for its mix design.

Research Progress on Fiber-Reinforced Recycled Brick Aggregate Concrete: A Review.

The addition of fibers to strengthen recycled concrete can strengthen the inherent deficits and deficiencies of concrete containing recycled aggregates to some extent and enlarge the concrete's application range. In order to further promote the development and application of fiber-reinforced brick aggregate recycled concrete, the research results regarding its mechanical properties are reviewed in this paper. The effect of the content of broken brick on the mechanical properties of recycled concrete and the effects of different categories and contents of fiber on the basic mechanical properties of recycled concrete are analyzed. The problems to be solved in research on the mechanical properties of fiber-reinforced recycled brick aggregate concrete are presented, and the related research suggestions and prospects are summarized. This review provides a reference for further research in this field and the popularization and application of fiber-reinforced recycled concrete.

Size effect on dynamic compressive failure mode and mechanical properties of recycled concrete

AbstractIn order to study the size effect behavior of recycled concrete under dynamic compression load, a meso‐scale model of recycled concrete was established. The particle size of coarse aggregate, replacement ratio of recycled coarse aggregate, and section size were used as parameters to explore the mechanical properties of recycled concrete under uniaxial dynamic compression load, such as failure mode, compressive strength, peak strain, and residual strength. The effects of strain rate, particle size of recycled coarse aggregate, and replacement rate of recycled coarse aggregate on the size effect of dynamic compression of recycled concrete were further analyzed. The results showed that under uniaxial dynamic compression load, the damage degree of recycled concrete deep and along with the change of the strain rate change, recycled concrete dynamic compression strength and strain rate were positively correlated. There is the critical strain rate is 1/s, which weaken the influence of the size effect, when the strain rate reaches 10/s, the dynamic compressive strength of recycled concrete increases with the increase of section size. At the same time, when the strain rate is high, the particle size of recycled coarse aggregate and the replacement rate of recycled coarse aggregate have little effect on the size effect behavior of recycled concrete.

Study on macroscopic mechanical properties and mesoscopic damage mechanism of recycled concrete with metakaolin under sodium sulfate erosion environment

The sodium sulfate resistance of recycled concrete (RC) under dry-wet (DW) cycle was studied, and the mesoscopic damage mechanism of RC under uniaxial compression was revealed by using statistical damage theory. The substitution rate of metakaolin (MK) and the number of DW cycles were considered in the test variables. The microstructure of RC was characterized by acoustic emission (AE), scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrometer (XRF). The results showed that with the increase of the number of DW cycles, the peak stress and elastic modulus of the specimen increased at first and then decreased, and the peak strain and mass change rate tended to increase. When the cycle times extended from 0 to 120, the peak stress of MK0 increased from −37.2 MPa to −50.7 MPa and then decreased to −29.1 MPa. The deterioration degree and mechanical properties of RC were improved by adding MK. The peak stress of MK15 increased by 26.4% and 16.4% respectively when it was cycled for 0 and 120 times compared with that of MK0. Based on the statistical damage theory, it was considered that there were 2 mesoscopic damage modes of fracture and yield, and the effective stress dominated the damage evolution of specimen during the failure process. The peak state and critical state were distinguished, and the mean values of σcr/σp and εcr/εp were 0.884 and 1.392 respectively. This paper provided experimental support for improving the sulfate resistance of RC, and provided theoretical basis for the use of in erosive environments.

Study on Mechanical Properties and Mesoscopic Numerical Simulation of Recycled Concrete

To obtain the mechanical properties of recycled concrete (RC) under different replacement rates (RRs) of recycled coarse aggregate (RCA), a quasi-static uniaxial compression test, a uniaxial splitting tension test and a uniaxial dynamic compression test of RC with replacement rates (RRs) of 0%, 20%, 40%, 60%, 80% and 100% were carried out. ABAQUS was used to investigate the cracking and failure of RC. The results showed that, when the RR was less than 60%, the uniaxial compressive and tensile strengths of RC decreased with the increase in RR, but slightly increased when RR was greater than 80%. Under impact load, the dynamic compressive strength of RC increased linearly with the increase in the strain rate, showing an obvious strain rate effect. With the increase in RR, the strain rate sensitivity of RC gradually decreased. The concrete damage plastic (CDP) model can describe the mechanical behavior of RC well. The damage and failure of RC occurred first at the old interface transition zone (ITZ) and old mortar. As the strain rate increases, the damage and failure rate of the specimens is intensified. Research on the mechanical properties of RC can provide a basis for the application and promotion of RC technology.

Research on eccentric compressive behavior of steel fiber reinforced recycled concrete-filled GFRP tube columns

Recycled concrete-filled GFRP tube (CFGT) columns can not only meet the recycling of waste concrete but also use FRP tubes to improve the mechanical properties of recycled concrete. This paper proposes a new structural form of steel fiber reinforced recycled concrete-filled GFRP tube column, and carries out research on the performance of CFGT column under eccentric compression. The variables considered in the experiment include GFRP tube thickness, the replacement rate of recycled coarse aggregate (RCA), steel fiber volume content, and initial eccentric distance. The bias bearing capacity, load-lateral mid-span deflection relationship, and nominal stress–strain relationship of the columns was analyzed. The tested results indicated that the addition of steel fiber kept the core concrete relatively intact after the specimen was destroyed and finitely compensated for the negative effect of recycled concrete on the whole specimen. In addition, a finite element model which was in good agreement with the experimental results was established, and the relatively complete Nu-Mu curves and Nu/N0-Mu/M0 curves were obtained by parameter analysis. Finally, formulas for calculating the bias bearing capacity and the corresponding mid-span bending moment of CFGT columns were proposed.

Analysis of dynamic size effect of recycled concrete using base force element method

AbstractA 2D meso models of recycled concrete with different sizes is established using the base force element method. The specimens are loaded with different strain rates. The meso damage of recycled concrete is analyzed. In addition, the structural performance of specimens under the joint actions with strain rate and size are also studied. The simulation results find that the compressive strength has little difference when the values of strain rates are lower than 0.1 s−1. The greater the strain rates, the greater the difference of compressive strength between different sizes when strain rates are larger than 0.1 s−1. In addition, the Bažant statistical theory can be used to analysis the mechanical properties of recycled concrete. Besides, a modified formula in calculating the dynamic size effect of recycled concrete is also given based on the Bažant statistical size effect theory.

Properties investigation of recycled aggregates and concrete modified by accelerated carbonation through increased temperature

Carbonation can modify waste concrete aggregate and sequester CO2; however, the slow reaction speed in a room environment limits its industrial application. In this study, the carbonation reaction of recycled coarse aggregates were accelerated at 70 °C. The physical properties of the recycled coarse aggregate before and after accelerated carbonation treatment and the mechanical properties of recycled concrete were tested and evaluated. Based on the results, an increased carbonation temperature can accelerate the carbonation reaction rate of the recycled concrete aggregate. The calcium hydroxide contained was fully carbonated in the first 12 h. Carbonation modification reduced the water absorption rate to 23.6% and the crushing value to 36.2%. Moreover, the mechanical performance of recycled concrete mixed with carbonation-modified aggregates was evaluated through a uniaxial stress–strain constitutive test. The 28 d compressive strength showed a 14.2% increase at 100% substitution of recycled modified aggregates relative to recycled aggregates. The elastic modulus and brittleness of the recycled concrete were also improved.