Concrete Production Research Articles

Assessment of the physical and mechanical characteristics of sand for the production of foam concrete using the two-stage foam injection method

The article presents the results of experimental studies of the properties of quarry sand to assess their suitability for use in the production of foam concrete. The sites of quarry sand extraction in the territory of the Akmola region are analyzed and their physical and mechanical characteristics are characterized. Evaluation of the physical and mechanical characteristics of sand was made for four types of sand. The main evaluation parameters were: particle size distribution, homogeneity, shrinkage, density and moisture content of sands. The results of the study showed that the physical characteristics of sands vary depending on their type, which indicates the differences in the natural composition and properties of these materials. Evaluation of the homogeneity of the different types of sands confirms the significant differences between the types. The highest homogeneity (xmax=77.45; xmax-1=14.98; Cc=73.5%) was observed in type 1 sand, while type 4 sand shows the minimum degree of homogeneity (xmax=47.30; xmax-1=42.28; Cc=8.7%). According to the test results, the maximum values of both densities in type 2 are: ρd=1.519 g/cm2, ρw=1.951 g/cm2, and the minimum values of both densities in type 4 are: ρd=1.438 g/cm2, ρw=1.894 g/cm2. The maximum natural moisture content in Type 1 samples is vn=9.5%, while the minimum values are 7.6% and 7.2% (Type 2 and 4). The obtained private density values have a high degree of convergence because the coefficients of variation have very low values: for Type 1 sands are 0.1-0.3%; for Type 2 sands are 0.7-0.8%; for Type 3 sands are 0.5-0.7%; for Type 4 sands are 0.4-0.6% (variation of private density values of dry and wet sands, respectively). Analysis of the results of tests on the shrinkage of samples showed that the maximum shrinkage is observed for sands of type 1 equal to 15.63%, while the minimum shrinkage is characteristic of samples of type 3 and 4 (11.25% and 11.88%). Taking into account the suitability of sand for the production of foam concrete, the most preferable is Type 1 sand mined in the Eltok building sand deposit.

Predicting the impact of adding metakaolin on the splitting strength of concrete using ensemble ML classification and symbolic regression techniques –a comparative study

The mechanical characteristics of concrete are crucial factors in structural design standards especially in concrete technology. Employing reliable prediction models for concrete’s mechanical properties can reduce the number of necessary laboratory trials, checks and experiments to obtain valuable representative design data, thus saving both time and resources. Metakaolin (MK) is commonly utilized as a supplementary replacement for Portland cement in sustainable concrete production due to its technical and environmental benefits towards net-zero goals of the United Nations Sustainable Development Goals (UNSDGs). In this research work, 204 data entries from concrete mixes produced with the addition of metakaolin (MK) were collected and analyzed using eight (8) ensemble machine learning tools and one (1) symbolic regression technique. The application of multiple machine learning protocols such as the ensemble group and the symbolic regression techniques have not been presented in any previous research work on the modeling of splitting tensile strength of MK mixed concrete. The data was partitioned and applied according to standard conditions. Lastly, some selected performance evaluation indices were used to test the models’ accuracy in predicting the splitting strength (Fsp) of the studied MK-mixed concrete. At the end, results show that the k-nearest neighbor (KNN) outperformed the other techniques in the ensemble group with the following indices; SSE of 4% and 1%, MAE of 0.1 and 0.2 MPa, MSE of 0, RMSE of 0.1 and 0.2 MPa, Error of 0.04% and 0.04%, Accuracy of 0.96 and 0.96 and R2 of 0.98 and 0.98 for the training and validation models, respectively. This is followed closely by the support vector machine (SVM) with the following indices; SSE of 7% and 3%, MAE of 0.2 and 0.2 MPa, MSE of 0.0 and 0.1 MPa, RMSE of 0.2 and 0.3 MPa, Error of 0.05% and 0.06%, Accuracy of 0.95 and 0.94, and R2 of 0.96 and 0.95, for the training and validation models, respectively. The third model in the superiority rank is the CN2 with the following performance indices; SSE of 15% and 4%, MAE of 0.2 and 0.2 MPa, MSE of 0.1 and 0.1 MPa, RMSE of 0.3 and 0.3 MPa, Error of 0.08% and 0.07%, Accuracy of 0.92 and 0.93 and R2 of 0.92 and 0.93, for the training and validation models, respectively. These models outperformed the models utilized on the MK-mixed concrete found in the literature, therefore are the better decisive modes for the prediction of the splitting strength (Fsp) of the studied MK-mixed concrete with 204 mix data entries. Conversely, the NB and SGD produced unacceptable model performances, however, this is true for the modeled database collected for the MK-mixed Fsp. The RSM model also produced superior performance with an accuracy of over 95% and adequate precision of more than 27. Overall, the KNN, SVM, CN2 and RSM have shown to possess the potential to predict the MK-mixed Fsp for structural concrete designs and production.

Statistical assessment of the factors influencing fly ash reactivity

Siliceous fly ash is a pozzolanic supplementary cementitious material often used in cement and concrete production. The influence of the chemical, mineralogical and physical properties of 75 siliceous fly ashes on their reactivity was examined in this study. The reactivity was analyzed by relative mortar compressive strength and a rapid screening test (a version of the R³ test). A statistical data analysis was carried out to evaluate the factors influencing the reactivity of the ash. The screening test was found to be able to predict the reactivity within short periods of time, while the relative strength is not a good measure for reactivity. It was also found that the TiO2 and chloride content of the fly ash can serve as an indicator for its reactivity.

Performance of coal gangue concrete with fly ash and ground-granulated blast slag: Rheology, mechanical properties and microstructure

This paper aims to examine the effect of coal gangue aggregate (CGA), fly ash (FA), and ground-granulated blast slag (GGBS) on the rheological, mechanical and microstructure properties of concrete. The rheological properties, compressive strength, splitting tensile strength, flexural strength, and uniaxial tensile behaviour of coal gangue concrete (CGC) were determined, and the microstructure of the concrete mixtures were investigated by use of XRD and SEM analyses. The results revealed the action mechanism of CGA and mineral admixtures on the microstructure and macroscopic properties of CGC. FA first increased and then decreased the yield stress and plastic viscosity, while GGBS considerably increased the yield stress and plastic viscosity. Furthermore, a constitutive model was established for CGC containing FA and GGBS under compression. The proposed stress–strain model for CGC is accurate and can be used for nonlinear analysis of structures made of this type of concrete. Moreover, the addition of FA and GGBS consumes calcium hydroxide, but increases products such as hydrated calcium silicate aluminate. These findings elucidate the understanding and optimisation of CGA use in concrete production, while contributing to lowering carbon emissions.

Efficiency of self-compacting concrete made with variable sustainable cementitious materials: A TOPSIS algorithm approach

The use of supplementary cementitious materials as a partial replacement for cement is taking the lead in the concrete production industry. Being known as by-products from various manufacturing properties, concrete produced with such materials is considered a sustainable alternative to normal concrete. Three different by-product materials have been investigated in this study for the production of sustainable self-compacting concrete (SCC), namely, ground granulated blast furnace slag (GGBS), fly ash (FA), and silica fume (SF). Compressive strength, production cost, and global warming potential (GWP) were the main testing parameters for the mixes' performances. Multi-criteria decision-making algorithm was implemented using the TOPSIS model to investigate the ultimate performance of those SCC mixes considering all tested parameters simultaneously. Results showed the best SCC performance can be attained when using about 60 % of GGBS as a partial replacement for cement.

Role of C-F-S-H/PCE nanocomposites on the hydration of Portland cement with varying gypsum levels

This study delves into the role of C-F-S-H/PCE (calcium-ferrite-silicate-hydrates/polycarboxylate ether) nanocomposites on the cement hydration with varying gypsum levels. It is found that the addition of C-F-S-H/PCE nanocomposites simultaneously promotes the dissolution of cement clinker and gypsum during early hydration. What’ more, the early hydration is further enhanced notably by C-F-S-H/PCE nanocomposites at moderately higher gypsum level without compromising the long-term compressive strength. It merits attention that the compressive strength of cement paste emerges as a factor intricately interwoven with not only its microstructure but also the content of AFt (ettringite) it harbors. Anyway, in the presence of the C-F-S-H/PCE nanocomposites, the faster depletion of gypsum leads to an earlier formation of AFm (monosulfoaluminate) whereas the morphologies of various hydration products remain unaffected. The findings demonstrate that the addition of C-F-S-H/PCE nanocomposites increases the demand for gypsum in cement and provide insights into the production of cement and concrete using seeding materials.

Rheological properties of high-performance SCC using recycled marble powder

Due to the impacts of cement manufacturing and depletion of the natural aggregates for concrete production, recycling of construction and demolition waste materials has become an alternative replacement to natural materials that lower their consumption and satisfy the environment. One of these alternatives is replacing cement with recycled materials from marble, ceramic, granite, and concrete wastes or even replacing the coarse aggregate with crushed marble and other stone wastes. Marble, granite, and natural stone wastes rapidly increase each year due to unmanaged waste disposal processes and the incremental increase in construction potential. Marble slurry, which comes from washing and cleaning marble surfaces, shows a filler effect by giving the concrete a denser and homogenous structure. This study evaluates the marble filler effects on the rheology in the fresh state of self-compacting concrete (SCC) through four SCC mixes by incorporating 10% marble powder (MP) and 33% fly ash (FA) as a partial ordinary Portland cement (OPC) replacement. Tests on paste and mortar were conducted to assess the suitability of the marble dosage on the water content and the superplasticizer amount. Spread flow and V-funnel tests were assessed. The results showed that mixes with MP required additional mixing water to ensure the same workability. Regardless of the high viscosity and air content, the overall developed marble SCC mixes reduced the cement quantity by up to 11% and provided excellent rheological properties like that of the reference mix. Besides the economic benefits, this transformation of waste to valuable materials involves environmental advantages and sustainability promotion.

Lightweight concrete with low-carbon artificial aggregates recycled from biomass ash and slurry waste

The development of artificial aggregates (AAs) significantly reduces carbon emissions of concrete production since the aggregates account for about 70% volume of all concrete ingredients. Therefore, a type of low-carbon AAs was prepared with full solid wastes of biomass ash (BA) and slurry waste (SW) through a pelletizing technique and carbonation curing methods. This study focused on evaluating the feasibility of AAs produced by the synergistic effect of BA and SW; identifying and optimizing the pelletization parameters through the response surface methodology (RSM) with experimental tests; analyzing the effects of blending amounts of BA on the properties of AAs; discussing the improvement of carbonation curing methods for AAs production; assessing the properties of the prepared lightweight concrete (LWC) with AAs. The results indicate the addition of 20wt% BA lightened the bulk density of AAs by about 13% but weakened strength by nearly half due to its porous characteristics. The appropriate incorporation of 5wt% BA could improve the individual pellet and cylinder compressive strength by about 2% and 16%, respectively. AAs cured in pressurized carbonation of 3 d and wet carbonation of 10min demonstrated similar enhancement effects. Pressurized and wet carbonation curing showed respective superiorities in terms of improving effect and curing efficiency. The effects of inclination angle and moisture content on the average particle size are more significant than those of rotation speed, while rotational speed has a dominant effect on the bulk density. RSM simulations identified the optimal inclination angle, rotation speed, and moisture content as 45°, 38.5r/min, and 37.5%, respectively. The LC40 high-strength LWC can be prepared by using full substitution pre-wetting AAs.

Mechanical Properties of Geo-Polymer Concrete by using Water Glass Solution

The environmental concerns related to the production of cement in terms of the energy consumption and the emission of CO2 lead to the search for more environmentally viable alternatives to the cement. One of those alternative materials is Fly ash and GGBS Where Fly ash (FA) and Ground Granulated Blast Furnace Slag (GGBS) is used not as a partial replacement to cement but as the sole binder in the production of concrete. The performance of fly ash and GGBS based materials with sodium silicate (water glass) as an activator was studied

Investigate the mechanical behavior of alkali-activated slag mortar using sustainable waste sodium silicate-bonded sand as an alkali activator and carbon free aggregate

Various products generate different types of industrial by-products based on their production characteristics and procedures. Therefore, an accurate classification of these characteristics would contribute significantly to achieving the goals of resource recycling and environmental protection. This study focused on Waste Alkali-Activated Slag Mortar (W-AASM). In the past, inorganic aggregation technology was successfully adopted to replace conventional concrete binding materials and reduce cement usage. Besides utilizing inorganic aggregation technology, the study has introduced a novel industrial by-product known as Waste Sodium Silicate-Bonded Sand (WSSS). WSSS not only serves as a substitute for sodium silicate in alkali-activated agents but also acts as a complete replacement for fine aggregates in mortar. The experimental findings showed that, in addition to fulfilling the original strength requirements of concrete, it results in a significant reduction in cement consumption, minimizing the extraction of natural resources, and decreasing the overall cost of Alkali-activated concrete production. The study highlighted the advantage of WSSS and showed a new dimension of waste foundry sand application in the concrete industry. This method leads to the recycling of waste materials and their optimal use, and as a result, leads to a sustainable ecosystem. The results of this study can be applied to secondary structures in civil engineering and construction projects in the future, such as precast concrete products, concrete pavements, or roads.

Radiation shielding properties of heavy-weight concrete and heavy-weight geopolymer concrete incorporating nano-ZnS

The population growth and the subsequent increase in energy demand for buildings require the widespread use of sustainable materials in the construction industry. Therefore, geopolymer concretes (GPC) are expanding with the ability to emit less greenhouse gases (GHG) compared to conventional concrete. In this study, the effect of adding different content of Zinc sulfide nanoparticle (nano-ZnS) 0, 1.5, 3, 4.5, and 6 % by weight of cement on density (ρ), compressive strength, gamma ray radiation protection characteristics, and microstructure based on scanning electron microscope (SEM) is investigated in heavy-weight concrete (HWC) and heavy-weight geopolymer concrete (HGC). The results have shown that nano-ZnS nanoparticles improve the strength and gamma ray shielding properties of HWC and HGC by modifying the microstructure so that by adding the optimal amount of 6 % nano-ZnS, the maximum compressive strength for HWC and HGC was obtained by 57.4 and 41.5 %, respectively. In addition, the highest linear attenuation coefficient (µ)was obtained with the addition of 4.5 % nano-ZnS for HWC and HGC, 12.8 and 8.9 %, respectively.Furthermore, the life cycle assessment (LCA) of the three phases of raw material production, transportation and concrete production has revealed that HGC has emitted 41.5 % less CO2 compared to HWC. In general, HGC in the presence of the optimal amount of nanoparticles has shown a more visible improvement in compressive strength and gamma ray shielding properties. In addition, HGC as an environmentally friendly material, has significantly reduced the emission of CO2.

Mechanical and chemical effects of incorporating stone powder residue in mortars

The construction industry is actively integrating technological innovations to optimize processes and mitigate solid waste in response to global challenges due to population growth and globalization. In this sense, this work addresses the imperative of sustainable development and waste decrease in construction. The research delves into using solid waste, such as ceramic block waste, granites, and marbles, in concrete and mortar production, highlighting challenges related to porosity and reduced mechanical strength. Additionally, the study investigates the incorporation of fibers to enhance the tensile strength of mortars. The main goal is the analysis of stone waste incorporation in mortar production, replacing 10% of sand, cement, and lime by considering particle size, water absorption, and chemical properties of stone powder. Experimental procedures involved cement of type 2, fine sand, and hydrated lime, with sieving systems applied for sand particle size testing. Compressive strength tests of a set of mortar compositions, including reference and modified proportions, were performed. chemical analysis through X-ray fluorescence (XRF) revealed composition aspects of stone powder and its impact on cementitious composites. Finally, it is advanced insights into compressive strength, particularly when the sand is replaced by stone powder, leading to the potential of stone powder to enhance sustainability in construction practices.

Sustainable reuse of waste ceramic tiles powder and waste brick powder as a replacement for cement on green high strength concrete properties

Nowadays, reducing construction waste has grabbed the attention. As bricks and ceramic tiles represent more than 50% of the ceramic waste in many European countries. Thus, the recycling of this waste type is one of the most significant challenges within the paradigm of the circular economy. This paper investigated the impact of substitution levels of cement by waste ceramic powder (WCP) and waste brick powder (WBP) at 0%, 5%, 10% and 15%, on the HSC characteristics. The WBP and WCP materials were characterized in detail by laser granulometry, XRF and XRD measurements, followed by standard mixing, production, and curing of concrete samples. The experiments on dry density, modulus of elasticity, flexural strength, splitting tensile strength, compressive strength, resistance to sulfate attack, water absorption and ultrasonic pulse velocity were conducted to evaluate the hardened properties of concrete. It was demonstrated that the durability and strength of concrete containing WBP and WCP as partial replacements for cement are marginally inferior to those of the control sample. On the other hand, samples containing WBP had a lesser negative effect on HSC properties in comparison with samples containing WCP. However, employing a 5% WBP with 10% WCP mixture enhanced the characteristics of the HSC in comparison to samples containing various percentages of WCP individually. In addition, the microstructure analyses revealed that the addition of 10% WCP and 5%WBP to HSC specimens resulted in higher hydration products and a slightly denser concrete matrix compared to samples containing various percentages of WCP individually. Research findings indicate that a 15% substitution of cement with WCP or WBP illustrated an environmental benefit in concrete production due to a 13.1% reduction in specific energy consumption.

Optimizing Concrete Properties Utilizing Marble Waste Powder with Fine Aggregate and Coconut Shell with Coarse Aggregate

The study delves into the innovative utilization of marble waste powder and coconut shell as potential additives in concrete production, aiming to enhance its mechanical and physical properties. By replacing 20% of coarse aggregate with coconut shell and varying the proportion of marble waste powder as replacements for fine aggregate at 25%, 50%, 75%, and 100%, a series of experimental mixes were formulated. Ordinary Portland cement of grade 53 served as the binding agent. Results indicated significant improvements in various engineering properties of the concrete, particularly in cube compressive strength, split tensile strength, and flexural strength. The study underscores the economic and ecological viability of incorporating these waste materials, highlighting their role in augmenting concrete performance while reducing environmental impact. This research contributes to advancing sustainable practices within the construction industry by optimizing material usage and enhancing concrete properties through innovative means. Key Words: Marble waste powder (MWP), Coconut shell (CS), Concrete.

Experimental Investigation of Sustainable Concrete Production using Blast Furnace as A Cement Substitute- A art of Review

The pursuit of sustainable construction practices has led to a growing interest in alternative materials that can reduce the environmental impact of traditional concrete production. This experimental study focuses on the utilization of blast furnace slag as a substitute for cement in concrete, aiming to assess its mechanical properties, environmental impact, and overall sustainability. The primary objectives of this research are threefold. Firstly, the study seeks to evaluate the mechanical properties of concrete by varying the content of blast furnace slag in the mix, with a specific emphasis on strength, durability, and structural performance. This involves conducting a comprehensive analysis of the concrete's compressive strength, flexural strength, and other relevant mechanical characteristics. Secondly, a life cycle assessment (LCA) will be employed to analyze the environmental impact of the concrete mixtures. This assessment will compare carbon dioxide (CO2) emissions, energy consumption, and overall sustainability of the concrete produced with varying percentages of blast furnace slag. The LCA will provide valuable insights into the environmental implications of using slag as a cement substitute, aiding in the identification of eco-friendlier concrete production practices. Lastly, the research aims to assess the environmental impact of blast furnace slag itself when employed as a cement substitute. This involves examining the production, transportation, and incorporation of blast furnace slag into the concrete mix, providing a holistic view of its sustainability across the entire life cycle. The experimental approach involves the meticulous design of concrete mixes with different percentages of cement replaced by blast furnace slag. The varying mix designs will be tested for mechanical properties, and the data obtained will be used to draw correlations between slag content and concrete performance. In summary, this research endeavors to contribute to the body of knowledge surrounding sustainable concrete production by exploring the mechanical, environmental, and sustainability aspects of utilizing blast furnace slag as a cement substitute. The findings of this study are anticipated to provide valuable insights for the construction industry to adopt more environmentally friendly practices while maintaining or enhancing concrete performance.

Copper heap leach residue aggregates in concrete: Properties and performance

This study assesses the feasibility of using copper heap leach residue (CHLR) as a sustainable alternative to natural aggregates in concrete production. The CHLR possesses flaky-angular shape grains with rough surface texture and microcracks, crystalline silica of 51.6 %, 6.1 mg/g silt-clay with a median particle size of 4.3 mm, and it becomes suitable for the partial replacement of natural fine and coarse aggregates after removing 4.2 mg/g fines through 60-minute wash. Concrete containing 25–75 % CHLR aggregates met design slump and air content of 125±25 mm and 2±0.5 %, respectively, while also demonstrating a negligible 2.9 % reduction in fresh density and 2.8 % increase in compaction factor. Concrete containing 50 % CHLR as a partial replacement of natural coarse and fine aggregates achieved compressive strengths of 47.3 MPa and 45.1 MPa at 28 days, while the compressive strength of control mix was 46.7 MPa. The mechanical properties significantly declined at 75 % CHLR incorporated concretes. The BSE-EDS analysis highlighted improved interfacial transition zone for CHLR aggregates with minimal microcracks at early age compared to the natural aggregates but developed interfacial transition zone microcracks with prolonged curing leading to a decline in mechanical strength development.

Optimizing Concrete Paver Block Production: A Linear Programming Approach for Enhanced Profitability in the Construction Industry

As an operational optimization (maximization or minimization) methodology, linear programming (L.P.) in operation research has proven successful in several areas by offering logical outcomes to challenging issues, including resource constraints. The study aimed to bridge the gap between theoretical applications of L.P. and the practical needs of the construction industry, specifically focusing on determining the optimal production quantities of 60 mm and 40 mm concrete paver blocks for Janta Udhog Pvt. Ltd. as a case study to achieve maximum profitability, offering essential new insights into how L.P. may successfully handle the complex problems encountered by businesses in this industry. An interview with the owner of Janta Udhog Pvt. Ltd. was conducted to obtain the primary data for the study. Secondary data such as sale records, monthly demand of each product, and inventory records were also obtained to formulate a linear programming model. The model was then solved using the LINGO software. This research underscores the optimal production recommendations for Janta Udhog Pvt. Ltd., advising the manufacture of 566.67 units of the 60 mm block and 350 units of the 40 mm block, leading to a maximum daily profit of NPR 2966.67. By applying linear programming techniques, these findings contribute to a more informed and strategic decision-making approach in the construction sector. The study illuminates the benefits of utilizing linear programming in challenging situations, providing valuable insights for academics, business owners, and decision-makers.

Optimal utilization of low-quality construction waste and industrial byproducts in sustainable recycled concrete

Construction and demolition waste (CDW) contains abundant low-quality recycled brick aggregates (RBA) that can potentially substitute natural aggregates (NA) in concrete production. However, recycled brick aggregate concrete (RBAC) shows inferior mechanical and durability performance compared to natural aggregate concrete (NAC), posing barriers to RBAC widespread adoption. This study investigates the combined influence of supplementary cementitious materials (SCMs) derived from industrial byproducts and hooked-end steel fibers (HSF) on properties of concrete with 0%, 50% and 100% RBAs from CDW as replacement for natural coarse aggregates (NCA). Addition of 0.5% HSF and 20%, 10%, and 30% fly ash (FA), silica fume (SF), and ground granulated blast furnace slag (GGBS) as cement replacement, respectively, were considered. Effect of different SCMs and HSF on compressive strength, splitting tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption (WA), freeze-thaw (FT) and acid attack resistance of concrete were studied. Results indicated that individual incorporation of HSF showed more contribution towards mechanical performance while combined incorporation of SCMs and HSF enhanced both mechanical and durability properties, along with reduction of up to 15.6% in embodied carbon of RBAC. Microstructural examination showed pore refinement and interfacial transition zone densification in RBAC with SCMs and HSF. This study demonstrates that sustainable RBAC with excellent mechanical and durability requirements could be produced using demolished brick waste and industrial byproducts.

Insight into the interaction mechanism of polycarboxylate superplasticizer and polyacrylamide in cementitious materials

Due to the economic and environmental benefits, manufactured sand is gradually replacing natural sand in concrete production. However, the residual polyacrylamide (PAM) in manufactured sand negatively affects the concrete rheology, and thus more polycarboxylate superplasticizer (PCE) is required. This study investigates the interaction mechanism between typical PAM and PCE, and further demonstrates their effect on cement hydration. Results show that there is competitive adsorption between PAM and PCE, and PAM occupies the adsorption sites of PCE on the surface of cement particles. Meanwhile, Ca2+ can combine PCE and PAM to form a polymer group, making part of PCE ineffective. Cationic PAM has the most significant effect on the adsorption of PCE on the surface of cement particles, whereas nonionic PAM has the least effect. The result of this study helps optimize the compatibility of PCE with manufactured sand concrete.

New cold-bonded artificial aggregate using a Ba(OH)2-activated cementless binder for cement-free concrete production

This study introduces cold-bonded cementless artificial aggregates using a Ba(OH)2-activated GGBFS binder system through a pelletization technique to produce complete cement-free concrete as an engineering application. The developed aggregate offers mechanical properties, achieving 10.8 MPa bulk crushing strength at 28 days and satisfying the requirements of lightweight aggregates according to EN 13055. Additionally, it complies with TCLP regulations, demonstrating excellent leaching resistance. The complete cement-free concrete was produced using the developed aggregate, demonstrating promising mechanical properties, exceeding 64.5 MPa compressive strength and 35.5 GPa elastic modulus, greater than previous studies. Economic analysis revealed a production cost of approximately USD 60.85/ton. Regression analysis identified a strong correlation (R2 = 0.9979) between disk revolving speed and diameter, enabling efficient production scaling across different scales (lab-scale, semi-pilot, and pilot). This research paves the way for a sustainable, cement-free, and natural aggregate-free concrete, achieved through the introduction of an eco-friendly, high-performance cold-bonded artificial aggregate and cementless binder that preserves mechanical integrity while delivering significant sustainability values.