Mixed Aggregates Research Articles

Second Life for Recycled Concrete and Other Construction and Demolition Waste in Mortars for Masonry: Full Scope of Material Properties, Performance, and Environmental Aspects

This review presents the scope of current efforts to utilize recycled construction and demolition waste in mortars for masonry. More than 100 articles are divided into groups pertaining to the type of mortar, different binder systems, the type of construction and demolition waste (CDW), and its utilization specifics. Cement-based mortars dominate this research domain, whereas recycled concrete is the main material employed to replace virgin aggregates, followed by recycled masonry and recycled mixed waste aggregates. Such application in cement-based mortars could increase water demand by 20–34% and reduce strength by 11–50%, with recycled concrete aggregates being the most favorable. Natural aggregate substitution is disadvantageous in strong mortars, whereas weaker ones, such as lime-based mortars, could benefit from this incorporation. The extent of this topic also suggests possibilities for different recycled material use cases in mortars for masonry, although the available literature is largely insufficient to infer meaningful trends. Nonetheless, the most relevant knowledge synthesized in this review offers promising and environment-conscious utilization pathways for recycled concrete and other construction and demolition waste, which brings opportunities for further research on their use in mortars for masonry and industrial-scale applications.

Influence of flocculation with dry-mixing on slump flow of high-strength concrete

The use of high-strength concrete in construction is expected to increase, and the manufacturing technology employed to produce such concrete needs to adapt to this rise. High-strength concrete has a workability that can vary significantly depending on the mixing conditions, even with the same mix design and in the same environment. This research focuses on the change in workability due to dry-mixing (i.e., mixing of fine aggregate with cement in the early stage) in the mixing process of a high-strength concrete mix using a revolving-double paddle mixer. As a result, it was confirmed that the slump flow value difference caused by dry-mixing was about 25 cm. Furthermore, Cryo-SEM (which can observe the specimens in the frozen state) image analysis revealed that dry-mixing causes flocculation of cement particles. The amount of admixtures adsorbed was then analyzed. This study concluded that flocculation affects the degree and timing of admixture adsorption in the later stages of the mixing process, leading to differences in concrete workability.

Life cycle assessment of concrete incorporating all concrete recycling products

This study evaluates the environmental impact of concrete incorporating locally available raw materials through life cycle assessment (LCA). It explores the integration of all concrete recycling products in the concrete mixes, including recycled concrete aggregates (coarse and fine) as alternative aggregates and ternary blended cements made with recycled concrete powder and waste perlite powder. With the declining availability of conventional supplementary cementitious materials like fly ash and blast furnace slag, alternative resources are essential. The developed concrete mixes reduced the climate change impact by up to 12% when ternary blended cements were used instead of ordinary Portland cement with the same aggregate mix. This can be attributed to the utilisation of industrial waste in the binder, which are locally available without any environmental burden other than transportation. The study maintains the same workability class and assesses the competitiveness of the developed mixes across strength classes, with notable environmental benefits recognised for the C50/60 strength class. A comprehensive assessment of the life cycle inventory (LCI) of the raw materials revealed significant variability between different sources for recycled aggregates, demonstrating the necessity for adopting a range of LCI data for alternative raw materials in the absence of specific data. Transparent reporting of production and transportation data is essential to improving LCA accuracy. The study shows the feasibility of developing circular concrete mixes that incorporate all products from the concrete recycling process, highlighting that optimising material performance and reducing reliance on conventional materials are crucial for increasing their attractiveness to the construction industry.

Evaluation of geotechnical, mineralogical and environmental properties of clayey soil stabilized with different industrial by-products: A comparative study

The utilisation of soil stabilization techniques employing binders like lime or cement enables the use of soils that are classified as disposable, thereby reducing the need for landfills and the consumption of natural resources. However, the production of lime and cement results in significant CO2 emissions. Therefore, the application of industrial by-products (IBP) for stabilizing expansive soils presents an opportunity to minimise the use of traditional binders. This study investigates the geotechnical, mechanical, mineralogical, and environmental properties of four IBP (biomass bottom ash, biomass fly ash, steel slag, and mixed recycled aggregate) combined with a silica-based nanomaterial for road layer applications. The technical feasibility of the use of IBP was demonstrated, especially in combination with nanomaterials, allowing a 66 % reduction in the percentage of added lime, obtaining significant improvements with minimal plasticity and swelling index and bearing capacity CBR values higher than 25 %, applying BBA, BFA and SS. An environmental assessment of leachate analysis was performance, showing an immobilization of heavy metals that makes the application of IBP feasible. In addition, a life cycle analysis study showed the environmental benefits of applying IBP, such as a 50 % reduction in CO2 emissions due to the reduction of lime, resulting from the use of these materials, thus promoting more sustainable economic models.

Life-Cycle Assessment and Environmental Costs of Cement-Based Materials Manufactured with Mixed Recycled Aggregate and Biomass Ash.

The development of new building elements, such as concrete and mortar with sustainable materials, which produce a lower carbon footprint, is an achievable milestone in the short term. The need to reduce the environmental impact of the production of cement-based materials is of vital importance. This work focuses on the evaluation of the life-cycle assessment, production costs, mechanical performance, and durability of three mortars and three concrete mixtures in which mixed recycled aggregates (MRAs) and biomass bottom ash from olive waste (oBBA) were included to replace cement and aggregates. Powdered MRA and oBBA were also applied as complementary cementitious materials with a reduced environmental footprint. Chemical and physical tests were performed on the materials, and mechanical performance properties, life-cycle assessment, and life-cycle cost analysis were applied to demonstrate the technical and environmental benefits of using these materials in mortar and concrete mixtures. This research showed that the application of MRA and oBBA produced a small reduction in mechanical strength but a significant benefit in terms of life-cycle population and environmental costs. The results demonstrated that finding long-term mechanical strength decreases between 2.7% and 14% for mortar mixes and between 1.7% and 10.4% for concrete mixes. Although there were small reductions in mechanical performance, the savings in environmental and monetary terms make the feasibility of manufacturing these cement-based materials feasible and interesting for both society and the business world. CO2 emissions are reduced by 25% for mortar mixes and 12% for concrete mixes with recycled materials, and it is possible to reduce the cost per cubic meter of mortar production by 20%, and the savings in the cost of production of a cubic meter of concrete is 13.8%.

Snapshot on 3D printing with alternative binders and materials: Earth, geopolymers, gypsum and low carbon concrete

The rapid development of 3D concrete printing now offers mechanical efficiency and freedom to push the limits of construction design. The digital manufacturing process holds potential for reducing carbon footprints through design optimization. Printable concrete, which is a mix of cement (based on ordinary Portland cement), aggregates, and admixtures, is attractive due to widespread and cost-effective constituents. However, many common formulations omit gravel, requiring higher cement paste volumes and inducing significant embodied carbon. Assessing the potential of low-carbon cements like Limestone Calcined Clay Cement (LC3), calcium aluminate cement (CAC), or magnesium-based cement for 3D printing is a current challenge that can address this issue. Tailoring these construction materials to printing applications and environmental needs now drives scientific exploration. This paper comprehensively reviews alternative materials and binders such as earthen materials, geopolymers, low carbon binders or gypsum-based materials, addressing fresh and hardened properties, developed digital processes, targeted applications, and discussing advantages and drawbacks of each alternative.

Experimental Study on Concrete Strength Behavior Using Plastic Waste as a Partial Replacement of Fine Aggregate

Waste from plastic materials is outstripped due to the growth of industrialization and urbanization. Plastic materials are non-biodegradable; decomposition is not possible all the time. The recycling of plastic materials by using them in concrete will be a great deal for plastic management. This research investigation aims to measure the optimum percentage of plastic in concrete without a reduction in concrete strength and shear behavior of reinforced concrete. Using the provision of Mix Design ACI 211.1-91, the M28 concrete grade was created. Plastic materials have been collected and passed through a No-4 sieve (4.76mm). The combination of fine aggregates and ground plastic materials (RPET, PP) in the weight fraction of fine aggregate mix (0%, 2%, 4%, 6%, 8%, 10%) was used in the concrete. Concrete beams (750´150´150 mm) are reinforced with two 12 mm longitudinal steel bars in the tension zone, with proper clear cover for testing the shear capacity. In order to conduct the compressive and tensile splitting test, concrete specimens with a diameter of 100 mm and a height of 200 mm were used. The experimental findings demonstrate guidelines for using plastic as a partial replacement within 2% to 4% of fine aggregate to produce the best outcomes.

Research on the evolution law of aggregate micro-texture during long-term wearing of asphalt pavement

The micro-texture of aggregates plays a very important role in anti-skid performance of asphalt pavement. Three kinds of aggregates, limestone, basalt and sandstone, were used to prepare asphalt mixture to study the evolution law of micro-texture of aggregates under long-term wear. One Third Scaled Model Mobile Load Simulator (MMLS) was used to conduct wear tests on asphalt mixtures under two working conditions: drying and water immersion. Laser confocal scanning microscopy (LCSM) was used to test and analyze the micro-texture evolution of the original aggregate, mixed aggregate, and accelerated loaded aggregate surfaces. The mechanism of texture evolution was analyzed based on the mineral composition, Vickers hardness, and micro-structure of the aggregate. The results show that wear can lead to varying degrees of polishing of the aggregate micro-texture, with limestone>basalt>sandstone, and the drying condition is more severe than the water immersion condition. The wear degree of the texture is closely related to the mineral composition and hardness of the aggregate. The more complex the mineral composition, the greater the hardness and hardness dispersion, the less likely the texture will be polished. The micro-texture indexes Ra and Rq have the highest correlation with anti-skid performance, and the relationship between them is obtained by fitting. Scanning electron microscopy (SEM) shows that the fine particles in sandstone are easy to fall off, which is conducive to the regeneration of texture, and is also the internal reason for its best anti-skid durability.

Supramolecular solvents based on hydrophobic natural deep eutectic solvents and primary amines for preconcentration and determination of enrofloxacin in milk

In this work, coacervation in primary amines solutions with hydrophobic natural deep eutectic solvents based on terpenoids and carboxylic acids was demonstrated for the first time. A liquid-phase microextraction approach was developed based on supramolecular solvent formation with primary amine acting as amphiphile and hydrophobic deep eutectic solvent making up mixed vesicles and serving as coacervation agent. Such supramolecular solvents could be used to separate wide range of substances from different aqueous media, such as food products, biological liquids and wastewaters. It is important that both hydrophobic and ionic interactions with supramolecular aggregates take place ensuring synergetic effect and better extraction ability, which is significant in separating relatively polar analytes. Different primary amines and deep eutectic solvents were investigated for liquid-phase microextraction of proof-of-concept amphoteric analyte (enrofloxacin, widely used veterinary fluoroquinolone antibiotic) and its determination by high-performance liquid chromatography with fluorescence detection using Shimadzu LC-20 Prominence chromatograph and RF-20A fluorescence detector. It was found that the supramolecular solvent based on 1-nonylamine, formed after addition of a deep eutectic solvent based on menthol and hexanoic acid (molar ratio of 1:1), provided maximum extraction recovery (85 %) and maximum enrichment factor (34). To characterize the extraction system, the composition of the phases was investigated, and cryo-transmission electron microscopy images were obtained. Vesicular aggregates were observed in the supramolecular solvent. The extraction mechanism was proposed in terms of formation of mixed aggregates to capture the analyte. Limit of detection was found to be 7 μg kg−1, while linear range of 20–250 μg kg−1 was established. Relative standard deviation values were lower than 7 %. Relative bias did not exceed 12 %.

Eco-friendly concrete: Combining treated wastewater and recycled aggregates.

The concrete industry is a significant consumer of drinking water and natural aggregates, such as sand and gravel. However, the scarcity of water and aggregate resources and the challenges associated with the disposal of construction and demolition waste prompted the exploration of alternative materials. This study investigates the feasibility of incorporating secondary treated wastewater from UASB reactors followed by trickling filters and mixed recycled aggregates as potential alternatives. To assess the viability of these alternatives, the study considered the replacement of 100% potable water with treated wastewater, as well as varying proportions of recycled gravel (20, 40, 60, 80, and 100%) and recycled sand (10, 20, 30, 40, and 100%). Physical and mechanical properties were negatively affected, but it was possible to reach compressive results over 40 MPa and splitting tensile strength over 4 MPa for almost all mixes. Regarding physical properties, the use of alternative materials caused poorer outcomes for density, water absorption, and air-void ratio. The limited magnitude of these detrimental effects indicates the potential of manufacturing concrete with the addition of combined treated wastewater and recycled aggregate as a viable strategy while enhancing reuse practices.

Influence of Bio-Additives on Recycled Asphalt Pavements.

The construction and maintenance of asphalt pavements is a resource-consuming sector, where the continuous rehabilitation of the superficial layers demands large volumes of non-renewable resources. The present work focuses on the design and characterization of asphalt mixtures for the binder layer of an asphalt pavement containing 50% reclaimed asphalt (RAP), in which seven different bio-based additives, identified as R1A, R1C, R2A, R2B, R2C, R3A, and R3B, were added to improve the workability, strength, and stiffness properties. The experimental program envisioned the hot mixing of aggregates and RAP with either a 50/70 or a 70/100 bitumen and, in turn, each of the seven bio-additives. The asphalt mixtures underwent the characterization of their densification properties; air voids; indirect tensile strength (ITS); indirect tensile stiffness modulus at 10, 20, 40, and 60 °C; and rutting resistance at 60 °C. The results highlighted that the performance in terms of workability and ITS of the resulting mixtures depends on the type of bio-additive and largely on the fresh bitumen type, while the stiffness at high temperature is not significantly affected by the presence of the bio-additives.

Mechanical Properties, Workability, and Experiments of Reinforced Composite Beams with Alternative Binder and Aggregate

Arguably the most important element in the sustainability of concrete development is the discovery of an optimal sustainable binder and substitution for the increasingly depleted reserves of natural aggregates. Considerable interest has been shown in alkali-activated materials, which possess good characteristics and could be considered environmentally friendly because of their use of secondary materials in production. The aim of this study was the determination of the mechanical properties of three different mixtures based on the same locally accessible raw materials. The reference mixture contained Portland cement, the second mix contained a finely ground granulated blast furnace slag instead of cement, and the third mixture contained a portion of light artificial aggregate. The experiments focused on the testing and mutual comparison of the processability of the fresh mixture and mechanical characteristics (like compressive and flexural strength, as well as resistance to high temperatures and surface layer tear strength tests). Reinforced concrete beams without shear reinforcement and with three levels of reinforcement were also tested with a three-point bend test. The results show that, overall, the mechanical properties of all the tested mixtures were similar, but each had its own disadvantages. For example, the blast furnace slag-based mixture had a more vulnerable surface layer or a debatable loss of bulk density in the light aggregate mix at the expense of the mechanical properties. One of the main results of the research is that it was possible to technologically produce beams from the alkali-activated concrete (AAC) mixture. Then, the performed beam experiments verified the mechanism of damage, collapse, and load capacity. The obtained results are essential because they present the use of AAC not only in laboratory conditions but also for building elements. In beams without shear reinforcement, the typical tensile cracks caused by bending and shear cracks appeared under loading, where their character was affected depending on the degree of beam reinforcement and loading.

Exploring the Use of Iron Ore Tailings in Concrete by Partial Replacement of Fine Aggregates

Concrete is the most durable, resilient, available and affordable material in the built environment. The manufacture of large quantities of iron ore has created difficulties for the environment and disposal. The utilization of IOT as fine aggregate in building material production is relatively feasible. Experiments were conducted to determine the suitability of iron ore tailings as replacement of fine aggregates for concrete. The iron ore waste was collected from Gua Iron Mines, Singhbum. Mix Design was carried out for concrete of grade M35 using standard practice for selecting proportions for normal weight. Iron ore waste replaced with fine aggregates in mixes by 30% and 35% respectively. The materials used for M35 grade of concrete is coarse aggregate 10-20mm, fine aggregate is of Zone 2, cement of 53 grade. Tests were performed on materials, for cement and fine Aggregate Fineness test, Specific Gravity were performed. Water absorption test, specific gravity, Impact value these were performed for Coarse aggregate. It was observed that compression values of concrete for 30% for 3 days its 13.703 Mpa, For 7 days its 16.503 Mpa, and for 28 it was 28.033 Mpa

Studying the effect of the ratio of water to binder and sand to aggregate on the hardness of concrete mixtures and compressive strength of roller-compacted concrete by experimental method

In roller-compacted concrete technology, withthe use of low water and cement content, the concrete mixture after kneading has high hardness and compaction equipment must be used to compact and shape the product.Therefore, the content of mixing water, binder, and aggregate are considered decisive factors, greatly affecting the properties of roller compacted concrete in both the fresh state and the hardened state.The paper uses the mathematical method of two-factor rotatable central compositional planning to simulate the effect of volumetric ratios of water-binder (VN/VCKD) and sand-aggregate (VC/VCL) on the objective functions of the test. The selected objective functions are the hardness of the concrete mixture and the compressive strength of the roller-compacted concrete at the age of 28 days.From the obtained objective functions, it is shown that both control variables VN/VCKDand VC/VCLhave a significant influence on the valuesof the experimental model. When the VN/VCKDratio increases, the water content contributes to increasing the plasticityand reducing the hardness of the concrete mixture. At the same time, excess water exists in the concrete mass in the form of air bubbles,pores,and magnetism. That reduces the compressive strength of the product. Furthermore, the VC/VCLratio of the aggregate that is too small or too large tends to cause the compressive strength of the concrete to decrease.

PENGARUH SERAT BAMBU TERHADAP KAPASITAS LENTUR PELAT BETON CAMPURAN STYROFOAM DEGAN PERKUATAN TULANGAN WIREMESH

Lightweight concrete is a concrete technology innovation that is currently developing. The advantage of lightweight concrete is that it uses less time and costs compared to concrete in general but has the disadvantage of lower strength. This research aims to determine the effect of adding bamboo fiber on the flexural capacity of lightweight concrete slabs mixed with Styrofoam. The lightweight concrete mixture used is Styrofoam at 50% of the weight of the mixed aggregate. Variations in adding bamboo fiber with a diameter of 1 mm and a length of 40 mm are 0% and 0.5% of the cement weight. The test object consists of a lightweight concrete plate measuring 50 cm x 150 cm x 8 cm with wire mesh reinforcement with a diameter of 8 mm. Tests were carried out when the concrete was 28 days old by applying an even load gradually until the slab collapsed. From the test results, at a loading of 300 kg, the average deflection value for lightweight concrete slabs with reinforcement reinforcement with 0% bamboo fiber was 1.18 mm and for lightweight concrete slabs with 0.5% bamboo fiber was 1.57 mm. Lightweight concrete slabs mixed with bamboo fiber have a greater deflection than lightweight concrete slabs without a mix of bamboo fiber. This shows that the addition of bamboo fiber to lightweight concrete slabs does not increase the flexural capacity of the slab. The difference between theoretical calculations and testing is due to the theoretical calculation formula used in this research not taking into account the content and properties of Styrofoam in the plates. The two variations of concrete slabs used in the test did not experience any cracks and met the maximum allowable deflection requirements at loads reaching 300 kg.

LCA applied to comparative environmental evaluation of aggregate production from recycled waste materials and virgin sources

Nowadays, all productive sectors, including the construction industry, are facing the challenge of reducing their environmental impact. To achieve this objective, numerous actions are being carried out to access greater levels of environmental and economic sustainability. Techniques as Life Cycle Assessment contribute to quantifying environmental impacts, promoting a circular economy in a sector that consumes a high volume of resources, materials, and energy while generating large amounts of gaseous, liquid, or solid emissions. The present study aims to deepen our understanding of aspects that demonstrate the benefits of using RA instead of natural aggregates. This study not only quantifies the environmental impact but also explores the effects of potential improvements in the productive system and their impact on reducing environmental harm. The Life Cycle Assessment methodology is applied to quantify and compare the environmental impacts generated in the production of a ton of mixed recycled aggregates (MRA) from construction and demolition wastes, based on the data provided by plant managers. This is compared to the environmental impacts generated in the production of one ton of natural aggregates extracted from a quarry. The results revealed that the production of mixed recycled aggregate is more environmentally beneficial, confirming a reduction of 70.66% in environmental impacts during the production of recycled aggregates, in comparison to the natural aggregates extraction. Furthermore, the economic analysis demonstrates the economic advantage since the cost of producing recycled aggregates is over 30% cheaper than natural aggregates, being more competitive even when the transportation distances from the plant to the work sites exceed those of natural aggregates.Graphical

Influence of the Properties of Different Types of Recycled Aggregate on the Service Properties and Leaching of Paving Blocks Manufactured at Industrial Scale.

The literature shows that a circular economy can benefit some sectors such as the construction industry. This sector demands huge amounts of raw materials and produces waste when buildings and structures are demolished. This paper explores the possibility of manufacturing at industrial scale paving blocks using different types of construction and demolition wastes as aggregates, without modifying the commonly used industrial conditions. A total of four different recycled aggregates were used in this research. Both natural and recycled aggregates have been characterized. The dosages were optimized (three different formulations). Prefabricated tests have been carried out on the products manufactured in industrial plants and the evolution of mechanical properties over time has been analysed. The results obtained were analysed statistically by applying the principal component analysis (PCA) method. To ensure the security of the elements manufactured, the ionic leaching of the materials used as recycled aggregate and of the elements produced has been tested. The main implications of this research on the construction industry show that the majority of recycled aggregates used could replace 25% of the natural aggregate in manufactured precast concrete, that the properties of the aggregates should be taken into account in the different standards and that all paving blocks manufactured in this study can be considered environmentally safe (no risk of leaching) according to the Netherland Soil Quality Decree. Therefore, it is evident that it is possible to manufacture on an industrial scale paving blocks with mixed recycled aggregates, concrete and ceramic in nature, both with the fine and coarse fractions that meet the requirements of its reference standard UNE-EN 1338 and the Netherland Soil Quality Decree that evaluates environmental risks due to leaching.

Evaluating the influence of volumetric properties on back-calculated asphalt layer moduli using falling weight deflectometer data

The back-calculation process performed in pavement systems is the numerical analysis of captured deflections to estimate layer stiffness parameters. Prediction of fatigue performance in terms of back-calculated asphalt layer moduli by using a Falling Weight Deflectometer (FWD) has specific challenges in terms of testing protocol, skillset, and complex back-calculation analysis. The performance of the asphalt layer is primarily governed by extrinsic parameters such as temperature, vehicular transient loading characteristics, moisture content, and intrinsic parameters such as binder properties and aggregate mix properties. The role of volumetric properties of asphalt mixes contributes significantly to the back-calculated asphalt layer moduli in terms of the overall life of the structure. The asphalt layer moduli value is dependent on the traditional volumetric properties of asphalt mixes such as air voids in the mix, voids in mineral aggregate, and the percentage of bitumen mix. In this study, a total of 60 in-service pavement sections are identified from three different categories of roads to perform FWD tests and collection of asphalt layer core samples. A detailed laboratory investigation has been carried out to estimate the volumetric properties of different core samples. This study uses field investigations to determine the degree of interdependency between the volumetric characteristics of asphalt mixtures and temperature on the back-calculated layer moduli. Furthermore, the findings from this study are utilized to establish several correlations at the aggregate level, demonstrating strong relationships with R2 values ranging from 0.84 to 0.875. The developed model is validated and depicted in good agreement with the actual values.

Effect of Brick Aggregate Content on Performance of Recycled Construction-Solid-Waste Aggregate.

In road engineering, road construction requires a large amount of natural aggregate; its substitution with recycled construction-solid-waste aggregate not only saves resources but also reduces the burden on the environment. The main components of construction solid waste are concrete blocks and brick slag; the breakability of the latter can affect the performance of mixed recycled aggregate, which hinders the use of construction solid waste in road engineering applications. To analyze the applicability of recycled construction-solid-waste aggregate containing brick slag aggregate in the subgrade layer, the effect of brick aggregate content on the CBR (California bearing ratio) and crushing value of mixed recycled aggregates was evaluated based on laboratory tests, and the field compaction quality of the recycled aggregates was analyzed. The results show that the 9.5-19 mm mixed recycled aggregate samples were crushed to a higher degree during the compaction process. A brick aggregate content less than 40% had little effect on the performance of mixed recycled construction-solid-waste aggregate. It is recommended to use a 22 t road roller for five passes (two weak vibrations + two strong vibrations + one weak vibration) at a speed of 3 km/h in the main compaction stage of the subgrade filling.

Study on Slump and Compressive Strength of Gangue Based on Aggregate Size Gradation

In order to solve the ecological environment pollution caused by a large amount of coal gangue accumulation and the problems of poor conveying performance and low support strength of paste filling materials. Based on the standard slump test and uniaxial compressive strength test, the slump and compressive strength (post-coagulation) of gangue paste under different aggregate size aggregations were obtained through orthogonal experiments in this study. The results show that the slump of the gangue filling paste with four types of aggregate size gradations is negatively correlated with the mass fraction, and the slump of the filling paste with a coarser aggregate content is more obviously affected by the mass fraction The increase of fine aggregate content has a significant impact on the compressive strength of the filling paste, which shows a trend of first increasing and then decreasing. When the mixing ratio of coarse aggregate and fine aggregate is 5:5, the compressive strength of the paste reaches the best. In addition, different proportions of aggregate mixing cause the filling paste to form different skeleton structures, including the skeleton void structure at 7:3 or 6:4, the skeleton dense structure at 5:5, and the skeleton suspension structure at 4:6, which are decisive for the final performance of the paste. By analyzing the experimental results of the compressive strength and slump of the gangue filling paste, it was found that the relationship between the compressive strength and slump of the gangue filling paste is a power index function. Through data fitting, it was found that the regression coefficient of the fitting function is no less than 0.97, and the fitting effect is good for evaluating the strength of the filling paste under the aggregate size grading.