Fly Ash Replacement Research Articles

Doping Silica Fume Enhances the Mechanical Strength of Slag/Fly Ash Geopolymer Paste under Frost Attack

Benign design of alkali-activated slag/FA geopolymer paste has attracted increasing attention for optimizing its service performance. Therefore, the replacement of fly ash (FA) with 10 wt% silica fume (SF) is investigated by mechanical strength after freeze–thawing cycles and microstructure characterization. The results show that an appropriate dosage (30 wt%) of slag is necessary to prepare heat-free curing alkali-activated slag/FA geopolymer paste with excellent mechanical performance. The SF/slag/FA (SF:slag:FA = 10:30:60, wt%) geopolymer paste exerts an enhanced compressive and flexural strength of 95.2 and 3.2 MPa, respectively. Meanwhile, the doped 10 wt% SF facilitates the propagation of (N, C)-A-S-H chains, rather than the formation of C-S-H gels. It is evidenced by the absent exothermic peak at about 861 °C from the differential scanning calorimetry (DSC) curves. The pores volume and tortuosity also rise for the pore diameter < 20 nm from mercury intrusion porosimeter (MIP) results, corresponding to an improved freezing–thawing resistance with the residual compressive strength of 52.8 MPa and the weight loss of 10.5% after 300 freeze–thawing cycles. It explores a cost-effective and benign facile approach to designing heat-free curing alkali-activated slag/FA geopolymer paste with good freezing–thawing resistance.

Comparative environmental assessment of low and high CaO fly ash in mass concrete mixtures for enhanced sustainability: Impact of fly ash type and transportation

The effect of fly ash type on the sustainability of concrete mixtures has yet to be quantified. This study aims to assess the environmental impacts of low calcium oxide (CaO) and high CaO fly ash in mass concrete mixtures from Thailand. The study analyzed 27 concrete mixtures with varying percentages of fly ash as a cement replacement (0%, 25%, and 50%) for 30 MPa, 35 MPa, and 40 MPa compressive strengths at specified design ages of 28 and 56 days. Sources of fly ash have been located between 190 km and 600 km away from batching plants. The environmental impacts were assessed using SimaPro 9.3 software. The global warming potential of concrete is reduced by 22–30.6% and 44–51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High CaO fly ash has more environmental benefits than low CaO fly ash when utilized as a cement substitute. The reduction in environmental burden was most significant for the midpoint categories of mineral resource scarcity (10.2%), global warming potential (8.8%), and water consumption (8.2%) for the 40 MPa, 56-day design with 50% fly ash replacement. The longer design age (56 days) for fly ash concrete showed better environmental performance. However, long-distance transport significantly affects ionizing radiation and ecotoxicity indicators for terrestrial, marine, and freshwater environments. Furthermore, the results show that a high cement replacement level (50%) may not always have a reduced environmental impact on mass concrete when considering long-distance transportation. The critical distance calculated based on ecotoxicity indicators was shorter than those calculated using global warming potential. The results of this study can provide insights for developing policies to increase concrete sustainability using different types of fly ash.

Utilization of phosphorus slag as fly ash replacement in low-heat Portland cement blends: Comparative study of hydration behaviors, physical properties, and life-cycle assessment

This paper presents the benefits of utilizing phosphorus slag (PS) to replace fly ash (FA) in low-heat Portland cement (LHPC) blends. After the first three days, PS exhibits worse mechanical properties and lower hydration heat compared to FA, presumably owing to its retarding effect. Meanwhile, the mechanical properties of PS are approached that of FA at 180 days. Based on the Krstulovic-Dabic (K-D) model, the Qmax values of LHPC, L75F25 (where the letters stand for the material and the numerals indicate the composition percentage), L65F35, L75P25, L65P35, and L50F25P25 are: 370.4 J/g, 312.5 J/g, 323.6 J/g, 333.3 J/g, 322.6 J/g, and 238.1 J/g, respectively. The effects of pozzolanic reaction and pore structure refinement of PS are more pronounced than that of FA, resulting in the Qmax of PS being relatively higher compared to FA. The number of gel capillaries (d < 10 nm) in L75P25 is 12% higher compared to L75F25 at 90 days. The pozzolanic reaction in FA is mainly occurred within 3 days to 28 days. However, in PS the corresponding period is from 28 days to 90 days. Furthermore, the synergistic impact between FA and PS in LHPC ternary blends is further decreased the drying shrinkage and cumulative heat, increases the H/LHPC content, and refines the pore structure. L75P25 has the lowest strength-normalized cost, which is 0.069 $/t/MPa ∼ 0.100 $/t/MPa less compared to L75F25. LHPC-FA-PS ternary blends has pronounced advantages on the strength-normalized energy consumption and carbon footprint. The strength-normalized carbon footprint and energy consumption of L50F25P25 are 1.89 kg/t/MPa and 5.57 MJ/t/MPa lower compared to L75F25, respectively.

Workability Assessment of Pumpable Structural-Grade Heavy-Weight Concrete Using Novel Coaxial Cylinder Method

The mixture proportioning of heavy-weight concrete (HWC), as seen from the literature, is primarily based on a trial-and-error approach; even so, data from the literature indicate that obtaining high-slump mixtures for high density levels (more than 3.1 g/cm3) is difficult. Because heavy-density aggregates are prone to segregation at high slump, a low water to cement ratio is generally used for HWCs, and full-scale pumping trials are needed for checking pumping placement. For structural-grade HWCs used in nuclear facilities and specific infrastructure such as tunnel cross-rail floating slabs, rheological properties are needed to quantify the workability for pumping placement. Because use of rheological assessment methods using sophisticated rheometers cannot be realized easily onsite, a novel coaxial cylinder method is proposed in this study for determining the yield stress of HWCs delivering 3,800 to 3,900 kg/m3 density. The device proposed in this study is portable and can be used also onsite. Four structural-grade hematite aggregate HWCs, with design strengths varying from 40 to 70 MPa, were designed with ordinary portland cement. To understand the effect of fly ash addition on rheological behavior, one of the structural-grade HWC with three different levels (15%, 25%, and 35%) of fly ash was investigated. For referring the initial workability and workability retention properties of HWCs used in jobsite pumping, the conventional slump test values of the mixture were compared with yield stress measurements. Experimental investigations suggested that the method proposed in this study are able to adequately capture the workability characteristics required for pumpable mixtures. Further, it was seen that 35% partial replacement of fly ash resulted in 100% reduction in yield stress of HWC mixtures. Fly ash replacement (15% to 35%) did not significantly alter the hardened concrete density (3,800 kg/m3); however, attainment of the specified compressive strength depended on the replacement level of fly ash and extended curing period.

Mechanical and durability studies on fly ash based fibre reinforced concrete

The purpose of this study is to determine the fresh and hardened properties of fibre reinforced concrete along with durability properties with steel fibres (SF) and jute fibres (JF). This study presents properties of concrete prepared with Fly ash (FA) as a partial replacement to Ordinary Portland Cement along with the fibres. Concrete mix of M30 grade was prepared as per IS code guidelines. The specimens were prepared with 5, 10, 15 and 20 % Fly ash replacements along with 0.5, 1.0, 1.5 and 2.0 % Steel and Jute fibre replacements with respect to the binder. For comparison, control concrete mix corresponding to M30 grade was prepared with 0% FA and 0% fibres. Variation in workability with the addition of fibres was determined with the help of slump cone test. Various mechanical strength tests were conducted on the specimens to observe that the strength was enhanced due to addition of fibres. Ultra-sonic pulse velocity test was conducted to determine the strength of prepared specimens in non-destructive way and compared with destructive compression strength values. Durability tests - Carbonation, Acid attack, Sorptivity and Rapid chloride ion penetration tests were conducted to determine the optimum percentage of fibre replacement along with fly ash replacement for long term durability. According to the experimental results, adding 15% fly ash and 1.5% fibres enhanced the mechanical properties, whereas adding 10 and 15% fly ash, 1.5 and 2.0% fibres enhanced the durability properties in comparison with the properties of conventional concrete. This paves the way for developing sustainable alternatives in the construction industry by utilization of marginal materials such as fly ash and jute fibres.

Study on the influence of waste glass powder replacing fly ash on the performance of concrete

The influence of glass powder replacing fly ash on concrete construction and mechanical properties is studied. By using glass powder with certain fineness to replace fly ash in the proportion of 25%, 50%, 75% and 100% respectively, the concrete test is carried out by controlling other ingredients in the mix proportion. The influence of glass powder replacement ratio on concrete slump, expansion, air content, carbonation depth and strength is studied. The test results show that when the specific surface area of glass powder is 600m2 / Kg, when the replacement rate is not more than 25%, its impact on concrete is within the controllable range, and it can replace part of the fly ash for use. This research can accelerate the full recycling of waste glass resources and promote the development of circular economy.

A literature review of the latest trends and perspectives regarding alkali-activated materials in terms of sustainable development

The purpose of the paper was to analyze trends in the formation of alkali-activated materials (AAMs) produced from alternative starting materials to blast furnace slags and fly ash. The research was reviewed on the basis of literature data from the past few years, which shows that the researchers are increasingly paying attention to the possibility of synthesis of AAM from such waste materials as industrial slags and ashes, concrete and demolition waste, red brick waste and glass waste. This is driven by the need to find competitive solutions to the commonly used blast furnace slags and fly ashes in the cement industry, which are also a source for obtaining traditional AAM. Analysis of material solutions has shown that these materials are being successfully used to produce new AAMs, with most of them being only a partial replacement for slags and fly ash. The article also points out that silicon- and aluminum-rich waste materials such as red mud, rice husks, and waste glass can be successfully used to activate AAMs materials, in place of typical activators in the form of sodium silicates or hydroxides, which in turn contributes to lowering the carbon footprint of AAMs. However, the future of this type of solution depends on several factors, the most important of which seems to be the understanding of the polymerization mechanisms of the more complex aluminosilicate systems and the achievement of reproducible physical and chemical parameters of AAM, resulting in strong and durable binders and, ultimately, construction materials made from them.

Early-Age Cracking Potential of Fly Ash High Performance Concrete Internally Cured with Super Absorbent Polymers

Abstract Early-age cracking is problematic for high performance concrete (HPC) made with a low water/binder ratio. The application of fly ash (FA) as a cement replacement can contribute to reduced CO2 emission and clinker factor, as well as improved durability of HPC. Super absorbent polymers (SAPs) were also applied for better curing and a higher rate of hydration to optimize the FA HPC. The current study utilized a temperature stress test machine to investigate the early-age cracking potential of FA HPC with internal curing by SAPs. Test results and the related analyses suggested that the introduction of internal curing alleviated the autogenous shrinkage, restrained stress, as well as tensile creep for HPC with 0 % and 20 % FA replacement level. The application of SAPs reduced the cracking potential of HPC with a low FA replacement level, whereas it aggravated the cracking when the FA replacement level was high.

USE OF HIGH SULFATE FLY ASH IN PUMICE BLOCKS

In order to reduce cement consumption, which is one of the significant factors in man-made carbon dioxide emissions, studies are being conducted on issues such as alternative building materials. Replacing cement with fly ash is at the forefront of cement reduction studies. However, the use of fly ash with a high sulfate content in structural elements is limited by European and American standards. Here the production of pumice stones used as wall material is discussed. Pumice blocks were made by replacing the cement in pumice blocks with high sulfate fly ash. High sulfate fly ash increased the late strength of pumice blocks by about 13%. In addition, as a result of a brief economic analysis for Türkiye, it turned out that wall costs could be reduced by up to 8% thanks to the replacement of fly ash. The mechanical and physical tests performed on the blocks produced concluded that the cement could be replaced with fly ash with a high sulfate content of up to 30%.

Experimental evaluation of alkali-activated and portland cement-based mortars prepared using waste glass powder in replacement of fly ash

The decreasing trend in coal fly ash production has led to a rapidly growing interest in finding alternative materials to replace fly ash in concrete. In this study, the use of glass powder to replace fly ash in concrete was investigated. The performance of portland cement and alkali-activated slag-based mortars containing fly ash (class F) or glass powder (aluminosilicate-based) was evaluated via a series of experiments, including fresh, physical, mechanical, and restrained cracking tests. Notably, a customized restrained shrinkage test was used to investigate the cracking potential. Results showed that the ultra-fine glass powder performed differently in the two binding systems. In the portland cement system, the use of glass powder yielded higher concrete mechanical performance compared to the concrete containing fly ash, while the opposite conclusion was obtained for the alkali-activated system. Comparing the alkali-activated system with the portland cement system, the alkali-activated materials with either fly ash or glass powder had higher free shrinkage and developed cracks much earlier under the restrained drying shrinkage. However, the alkali-activated materials maintained a high level of strain in the steel ring, which was primarily attributed to the development of multiple cracks and their different bonding at the mortar and steel interface.

Application of concrete produced from reused ready-mixed concrete wastewater filtration residue

During the production of ready-mixed concrete, waste slurry was filtered under pressure to obtain Wastewater Filtration Residue (WFR). Physical and chemical analysis of the WFR was conducted using methods such as XRD, SEM. The flowability and activity index of the cement mortar with composite admixtures, prepared by replacing fly ash (FA) with WFR powder at weight ratios of 0%, 25%, 50%, 75%, and 100%, were tested. Different strength grade concretes were prepared by replacing FA at weight ratios of 0%, 25%, and 50%, and replacing fine aggregate at weight ratios of 0%, 5%, and 10%, in order to analyze the variation of concrete strength. The results indicate the following: 1) The WFR was primarily composed of fine particles with various shapes and loose surfaces, making it suitable for concrete preparation. 2) WFR had poor flowability (59.83%) and hydration activity (51.7%), but FA addition improved both. Increasing FA content enhanced flowability ratio and hydration activity. At 1:1 FA-to-WFR ratio, flowability reached 81.44% and hydration activity reached 75.73%. 3) When WFR replaced FA (25%, 50%) or manufactured sand (5%, 10%) in concrete preparation, the strength of the concrete decreased with an increase in the WFR content. In low-strength grade concrete, the strength reduction was significant when WFR replaced FA. However, the strength reduction was less influenced by the design strength of the concrete when WFR replaced manufactured sand. 4) It was recommended to replace fine aggregate with WFR for concrete preparation, with the replacement ratio not exceeding 10% by weight.

Influence of mix proportioning parameters and curing regimes on the properties of ultra-high strength alkali-activated concrete

This study investigates the influence of mix proportioning parameters and curing regimes on the material properties of alkali-activated binder-based ultra-high strength concrete (AAB-UHSC). The effects of five groups of mix proportioning parameters (i.e., fly ash replacement ratio, silica fume replacement ratio, alkali to binder ratio, water glass modulus, and steel fiber content) and three curing regimes(i.e., ambient curing, standard curing, and hybrid curing) on the workability, compressive strength, flexural strength and microstructure development of AAB-UHSC were systematically evaluated. The results indicated that increasing the steel fiber and silica fume dosage negatively affected the flowability of freshly mixed AAB-UHSC. There existed an optimal alkali-to-binder ratio and water glass modulus in terms of flowability, compressive strength, and flexural strength, but the fly ash replacement ratio had a complex effect on the material performance of the AAB-UHSC. The microstructures of the specimens cured in hybrid curing regimes were denser, and fewer cracks were observed, which resulted in higher strength compared to specimens cured under ambient curing and standard curing conditions. The three types of curing regimes adopted barely alter the phases and molecular bonds of hydration products based on the XRD and FTIR results. In addition, the correlations between the compressive strength of the AAB-UHSC obtained under ambient curing conditions, standard curing conditions, and obtained under hybrid curing and standard curing conditions were analyzed, and the fitted results had higher correlation coefficients (R2).

Preparation of inorganic binder-stabilised material with iron tailings: strength formation and gradation optimisation

This study focuses on mechanical strength and gradation optimisation of inorganic binder-stabilised material with iron tailings for pavement engineering. The mechanical strength and compatibility of iron tailings mortar with various inorganic binders were explored. Mechanical strength formation of iron tailings mortar was analysed using hydration products, micromorphology and microstructures. Composition optimisation of inorganic binder-stabilised material with iron tailings was discussed using the central composite design-response surface method. Results showed that the mechanical strength formation of iron tailings mortar is primarily dependent on ettringite and calcium silicate hydrate (C–S–H) gels. Iron tailings mortars with an appropriate amount of lime or fly ash replacement of cement exhibit a denser structure and adequate pore structure distribution that help improve their mechanical properties compared with cement iron tailings mortars. To balance the amount of iron tailings and the strength of cement-stabilised material, optimal application conditions were proposed for different levels of highways.

Assessment of the Combined Effect of Silica Fume, Fly Ash, and Steel Slag on the Mechanical Behavior of Concrete

Every ton of cement produced emits half a ton of carbon dioxide, so there is an immediate need to limit cement use. Cementitious materials such as fly ash, silica fume, and steel slag can be substituted for cement in making concrete more rigid and stronger. This research work has been done to analyze the change in compressive strength in concrete, reducing the use of cement and coarse aggregate, in the case of varying percentages of cement replacement circumstances. To get this job done, there’s been conducted a variety of laboratory tests changing the partial cement replacement proportions with silica fume and fly ash and partial aggregate replacement with steel slag in the concrete mix. The test result showed that 15% silica fume, 10% fly ash, and 30% steel slag replacing proportion withstand more compressive load than the normal cement concrete mixture. The SEM test also supports the compressive strength test result by showing the internal bonding between the materials in the replaced binder-aggregate specimens. On the other hand, the flexural strength test came out with the best proportion of 15% cement replacement with fly ash and silica fume along with 10% coarse aggregate replacement with steel slag. The XRD patterns of the materials used also enumerate the standardization and testing procedures. The usage of sustainable cementitious materials like fly ash, silica fume, and steel slag incorporates the motivation behind reducing the industrial byproducts/wastes generated in such an amount that hampers our mother nature. The overall representation of this research will emancipate the initiatives taken toward greener and more sustainable construction.

Assessment of sustainable eco-processed pozzolan (EPP) from palm oil industry as a fly ash replacement in geopolymer concrete

This research focusses on the feasibility of using eco-processed pozzolan (EPP), a palm oil industrial by-product, as partial replacement for fly ash (FA) in the geopolymer concrete (GPC); in addition, the effect of another palm oil industrial by-product, palm oil clinker (POC) as the lightweight coarse aggregate in the EPP-based GPC was also investigated. The ratios of alkaline activator to binder and sodium silicate to sodium hydroxide were kept constant, and the specimens were cured at 60 °C for 24 h. The mechanical properties, namely compressive, splitting tensile and flexural strengths, and modulus of elasticity (MOE) were investigated; further, microstructural analyses such as SEM, XRD and EDX were conducted. The test results show that the utilisation of 10–30% of EPP as FA replacement produced the compressive strengths in the range of 28–39 MPa. The splitting tensile strength of both the lightweight (LW) and normal weight (NW) GPC, except for M6 containing 30% of EPP substitution, fulfilled the minimum requirement of 2.0 MPa. In addition, the flexural strength of GPC produced about 12% of the respective compressive strength. The lower MOE of LW GPC compared to the NW GPC is attributed to the lower stiffness and specific gravity of POC aggregates. The XRD analysis shows the evidence of geopolymerization products of quartz, sillimanite, magnetite, and almandine.

Effect of Bamboo Leaf Ash on The Properties of Geopolymer Concrete at Ambient Curing Temperature

As a result of the growing environmental concerns in the cement industry and the rising cost of building materials, alternative cement technologies have become an area of increasing interest. In this study, geopolymer concrete containing fly ash class F and bamboo leaf ash was chosen as a cement substitute in concrete manufacturing. This research was an experimental study evaluating the effect of bamboo leaf ash (BLA) on geopolymer concrete by addition as a partial replacement of fly ash. The test samples were 100 x 100 x 100 mm cubes and 300 x 150 mm cylinders at the ambient curing temperature. The design mix of C25 was used for this study. This research aimed to explore the suitability of the use of bamboo leaf ash as a mixing material in geopolymer concrete in more environmentally friendly industries. The properties that were investigated in this study are the basic aggregate tests, XRF analyses of BLA and fly ash, and workability tests by evaluating slump and compaction factor tests. In addition, compressive strength and splitting tensile strength of 28, 56, and 90 days. Therefore, in this study, various levels of bamboo leaf ash were utilized, including 0%, 5%, 10%, 15%, and 20% BLA. The alkaline liquid-to-binder ratio for all mixes was constant at 0.6, while the Na2SiO3 to NaOH ratio was 2.5. The test results of the workability show that the increased amount of bamboo leaf ash gradually reduces the alkaline liquid. The result of compressive and splitting tensile showed that fly ash substitutes that contained 5% and 10% of the bamboo leaf had higher strengths of about 38.7 MPa, 40.8 MPa, 4 MPa, and 4.22 MPa, respectively than other mixtures. Therefore, bamboo leaf ash can be one of the constituent materials used to improve the mechanical properties of geopolymer concrete

Effects of Waste Glass Powder on Rheological and Mechanical Properties of Calcium Carbide Residue Alkali-Activated Composite Cementitious Materials System.

As a municipal solid waste, waste glass undergoes pozzolanic activity when ground to a certain fineness. In this paper, calcium carbide residue (CCR) and Na2CO3 were used as composite alkali activators for a glass powder-based composite cementitious system. A total of 60% fly ash (FA) and 40% ground granulated blast furnace slag (GGBS) were used as the reference group of the composite cementitious material system, and the effects of 5%, 10%, 15%, and 20% glass powder (GP) replacing FA on the rheological behavior, mechanical properties, and microstructure of alkali-activated composite cementitious systems were investigated. The results showed that with the increase in GP replacing FA, the fluidity of the alkali-activated materials gradually decreased, the shear stress and the equivalent plastic viscosity both showed an increasing trend, and the paste gradually changed from shear thinning to shear thickening. Compared with the reference sample, the fluidity of the alkali-activated material paste with a 20% GP replacement of FA was reduced by 15.3%, the yield shear stress was increased by 49.6%, and the equivalent plastic viscosity was elevated by 32.1%. For the 28d alkali-activated material pastes, the compressive strength and flexural strength were increased by 13% and 20.3%, respectively. The microstructure analysis showed the substitution of FA by GP promoted the alkali-activated reaction to a certain extent, and more C-A-S-H gel was formed.

Effective utilization of agricultural ashes in development of sustainable geopolymer concrete

The use of concrete is widespread in the construction industry due to its successful and desirable properties. As industrial and urban development rapidly increases, the demand for concrete is also reaching new heights compared to other materials. In this regard, there is a pressing need for alternative materials to replace cement and industrial by-products. This paper proposes the effective utilization of agricultural ashes, including rice husk ash (RHA), bagasse ash (BA), and palm oil ash (PA), in geopolymer concrete. The study evaluates fly ash-based geopolymer concrete's compressive strength and microstructural performance by replacing fly ash with varying percentages of agricultural ashes. The results show that including agricultural ashes in the fly ash-based geopolymer blends yields higher strength than the 100% fly ash-based geopolymer concrete. However, using higher dosages of agricultural ashes decreases strength and forms micro-cracks in the geopolymer phases. Therefore, using 20% RHA or 15% BA or 15% PA as a precursor in fly ash-based geopolymer concrete can produce sustainable construction material and contribute to greener construction. Green concrete can help advance the circular economy and promote environmental protection.

The compressive strength and the setting time of partial replacement of fly ash by palm oil fuel ash on geopolymer paste and mortar

This study replaced fly ash with palm oil fuel ash (POFA) in geopolymer paste and mortar. The alkaline activator was a mixture of sodium silicate solution and sodium hydroxide solution with a ratio of 2.5. Three variables were evaluated: the raw material combination (100% fly ash and 25% POFA substituted to fly ash), the mass ratio of raw material to alkali activator (60/40, 65/35, and 70/30), and NaOH molarity (8 M and 10 M). The geopolymer mortar was utilized based on the highest compressive strength of geopolymer paste. The ratio of fine aggregate to binder was 65 to 35. The result showed that the compressive strength of geopolymer paste increased as NaOH molarity increased. 25% substitution of POFA for fly ash increased the compressive strength of geopolymer paste from 12.0% to 27% at 28 days. The raw material/ alkali activator ratio of 65/35 indicated the highest compressive strength. The POFA replacement for fly ash had a longer setting time than 100% fly ash. The compressive strength ratio of mortar to the geopolymer paste was 0.66 and 0.59 for the 65/35 and 70/30 ratios of raw material to alkali activator, respectively.

Recycling prestressed concrete pile waste to produce green self-compacting concrete

Construction and demolition waste is produced in large quantities and constitutes an overlooked resource with significant potential for recycling and reuse. In fact, recycled concrete aggregate (RCA) has a high resource value, although it is also the case that RCA has characteristics that complicate its reuse. This research study looks at the efficacy of producing green self-compacting concrete (SCC) using uniform in-situ prestressed concrete pile waste (RCA) as a replacement for natural aggregate and fly ash (FA) as a replacement for Type 1 Portland cement (OPC). In accordance with the European standard, the workability characteristics of the SCC mixtures were assessed using slump flow, T500 time, J-ring flow, L-box, and V-funnel tests. The hardened properties of compressive strength at 7, 28, and 91 days as well as pulse velocity, Young's modulus, and surface resistivity were also tested. Based on this study, it is possible to produce SCC with both RCA and FA that has better workability and hardened properties than does RCA and also to reduce the negative effects of the latter. SCC produced without coarse natural aggregates showed compressive strength above 50 MPa and maximum compressive strength above 74 MPa at 91 days. SCC produced in this way is, therefore, viable for industrial use.