Mineral Additives Research Articles

The Durability of Concrete Mortars with Different Mineral Additives Exposed to Sulfate Attack

For several years, extensive research investigations have been conducted examining the effects of acids commonly encountered by industrial facilities in manufacturing environments. Numerous studies have been conducted to examine the durability of concrete containing various chemical additives and fine metals when exposed to various acid solutions, as well as the preventive steps taken to avoid the deterioration of concrete associated with these acids. This research includes an examination of enhancing the effectiveness and function of concrete when exposed to sulfuric acid. It explores the use of waterproofing (WP) and complementary cementitious materials (SCMs), including silica fume Nano silica and fly ash, as well as a water-reducing additive. Cube-shaped samples measuring 100 x 100 x 100 mm were prepared and completely immersed in 2.5% dilute sulfuric acid solution for 90 and 180 days. . Compressive strength, tensile strength, and absorption tests were performed after 28 days, as well as after immersion in a 2.5% dilute acid solution for 90 and 180 days. The results revealed that after 90 days, there was a 31% reduction in compressive strength for mixtures with 25% FA and 5% SF, and a 46% decrease for mixtures containing WP, when compared to their corresponding results at the 28 day age under standard conditions. Mineral admixtures significantly reduce absorption rates. After 90 days, WP had 3% absorption during acid exposure, and after 180 days, the 25% FA and 5% SF mixture had 2.3% absorption. This results from reduced permeable voids due to decreased capillary pores, enhancing concrete durability. The findings also indicated that the impact of exposure to acid on the strength characteristics of concrete becomes more pronounced with prolonged exposure. In addition, the inclusion of NS, SF, and FA in cement concrete results in the development of a unique material that can meet the growing need for construction materials. Furthermore, this technique delivers economic and environmental benefits by minimizing pollution caused by waste products such as FA and SF, which are a residual by-products of thermal power plants and ferrosilicon production respectively.

Ocean alkalinity enhancement using sodium carbonate salts does not lead to measurable changes in Fe dynamics in a mesocosm experiment

Abstract. The addition of carbonate minerals to seawater through an artificial ocean alkalinity enhancement (OAE) process increases the concentrations of hydroxide, bicarbonate, and carbonate ions. This leads to changes in the pH and the buffering capacity of the seawater. Consequently, OAE could have relevant effects on marine organisms and in the speciation and concentration of trace metals that are essential for their physiology. During September and October 2021, a mesocosm experiment was carried out in the coastal waters of Gran Canaria (Spain), consisting on the controlled variation of total alkalinity (TA). Different concentrations of carbonate salts (NaHCO3 and Na2CO3) previously homogenized were added to each mesocosm to achieve an alkalinity gradient between Δ0 to Δ2400 µmol L−1. The lowest point of the gradient was 2400 µmol kg−1, being the natural alkalinity of the medium, and the highest point was 4800 µmol kg−1. Iron (Fe) speciation was monitored during this experiment to analyse total dissolved iron (TdFe, unfiltered samples), dissolved iron (dFe, filtered through a 0.2 µm pore size filter), soluble iron (sFe, filtered through a 0.02 µm pore size filter), dissolved labile iron (dFe′), iron-binding ligands (LFe), and their conditional stability constants (KFeL′) because of change due to OAE and the experimental conditions in each mesocosm. Observed iron concentrations were within the expected range for coastal waters, with no significant increases due to OAE. However, there were variations in Fe size fractionation during the experiment. This could potentially be due to chemical changes caused by OAE, but such an effect is masked by the stronger biological interactions. In terms of size fractionation, sFe was below 1.0 nmol L−1, dFe concentrations were within 0.5–4.0 nmol L−1, and TdFe was within 1.5–7.5 nmol L−1. Our results show that over 99 % of Fe was complexed, mainly by L1 and L2 ligands with kFe′L′ ranging between 10.92 ± 0.11 and 12.68 ± 0.32, with LFe ranging from 1.51 ± 0.18 to 12.3 ± 1.8 nmol L−1. Our data on iron size fractionation, concentration, and iron-binding ligands substantiate that the introduction of sodium salts in this mesocosm experiment did not modify iron dynamics. As a consequence, phytoplankton remained unaffected by alterations in this crucial element.

Physical, Mechanical and Microstructural Characteristics of Perlite-Based Geopolymers Modified with Mineral Additives

One of the promising raw materials for the synthesis of geopolymers is perlite, which is a natural low-calcium aluminosilicate. This research studied the physical, mechanical and microstructural characteristics of perlite-based geopolymers modified with different mineral additives that were prepared using different methods of introducing the alkali components and curing conditions. The experimental results of the consolidated perlite-based geopolymer pastes showed that curing conditions and the method of introducing the alkali component into the geopolymer matrix had a minimal effect on the average density while demonstrating a significant boost in compressive strength. So, after thermal treatment, the compressive strength increased by 0.63 to 11.4 times for the mixes when fresh alkali solution was used and by 0.72 to 12.8 times for the mixes with the 24 h conditioned alkali solution. Maximum-strength spikes from 1.1 MPa to 13.2 MPa and from 0.7 MPa to 9.7 MPa were observed for the mixes with kaolin when prepared with fresh and conditioned alkali solutions, respectively. It was also observed that thermal treatment facilitates the compaction of the matrix structure by 18% and 1% for the non-modified mix and the mix modified with Portland cement. Perlite-based geopolymers modified with Portland cement and citrogypsum demonstrated a significant reduction in the initial and final setting times with both methods of introducing the alkali solution. On the surface of mixes modified with citrogypsum, regardless of the curing conditions and method of introducing the alkali component, an efflorescence substance was observed. The microstructural analysis of the consolidated geopolymer perlite-based pastes containing citrogypsum demonstrated a loose structure and the presence of efflorescence, which can be associated with a retardation in interaction processes between alkali cations and the aluminosilicate component. EDS analysis demonstrated that the presence of such elements as oxygen, sodium and sulfur may indicate the efflorescence of unreacted sodium hydroxide (NaOH), citrogypsum (CaSO4) and the products of their interaction in the form of crystalline hydrates of sodium sulfate (Na2SO4).

Artificial neural network evaluation of concrete performance exposed to elevated temperature with destructive–non-destructive tests

In this study, it is aimed to predict the performance of concretes obtained by using supplementary cementitious materials (SCM) before and after high temperature using artificial neural network. Thus, in addition to contributing to sustainable development and circular economy by using waste materials in concrete production, predicting concrete strength using artificial neural network without the need for experimental studies will provide a great advantage in practice. In addition, it will also contribute to the literature in terms of determining the optimum amount of metakaolin to be used with fly ash in concrete production. Metakaolin, silica fume and fly ash were used as SCM in different proportions in concrete mixes. Accordingly, a total of 22 concrete series were prepared, one of which was the control series. Porosity, ultrasonic pulse velocity, pressure and tensile strength tests were applied to the series at the end of 7th, 28th and 90th curing periods before high temperature. In order to determine the strength losses after elevated temperature, porosity and compressive strength tests were applied at temperatures of 400, 600 and 800 °C. Mineral additive series showed positive mechanical properties up to 20%. However, it has been observed that the use of fly ash after a certain rate causes a decrease in strength. After elevated temperature, strength loss was observed in all series due to the increase in temperature, while it was observed that the rate of being affected by elevated temperature decreased as the percentage of metakaolin increased. Optimum mineral additive usage percentages were determined as 10% fly ash and 15% metakaolin. On the other hand, the use of mineral additives above the optimum level caused the performance of the concrete to decrease. Then, the concrete compression strengths obtained at 7th, 28th, and 90th days and at 400, 600 and 800 °C temperatures are taken as the outputs of the ANN. The artificial neural network provided the closest results to experimental data. Moreover, to prove the predictive performance of ANN, a comparative analysis was made with GPR, SVM and LR and the smallest value of the RMSE value is obtained with the ANN model. Finally, a fivefold cross-validation criteria was used to objectively present the performance of the model.

An investigation on the application of acrylic resin agent for fiber/matrix bond strengthening in green engineered cementitious composites (ECC)

Green cementitious materials are usually developed by the addition of high volumes of mineral fillers. However, the addition of minerals can result in the reduction of mechanical strength. ECCs obtain their superior mechanical behavior from a high volume fraction of fibers. In ECCs, the matrix’s strength and the bond between the fibers and the matrix is a critical parameter, and if it becomes weak, the whole composite becomes weak or fibers may pull out of the matrix. In this study on green ECCs, to increase mechanical strength and also fiber/matrix bonding, the acrylic resin is used in 4 contents (e.g., 0, 2, 4, and 6 % in weight). The tests performed on ECC and plain cement paste (PCP) included tensile, compressive, and flexural. The results show that the acrylic increases the tensile strength, from about 2.0 MPa, up to 20 %, and compressive strength increased from about 88 MPa to 100 MPa. Due to the increase in ductility, the energy-based indexes increase more significantly. Acrylic resin optimum content was measured as 1.5–2.7 % (by weight). The trends show that acrylic resin is more effective for ECCs, because, in addition to enhancing the matrix strength, the resin increases the bonding strength between the matrix and fiber. Seeking the relationship between the results, nonlinear regression was used, and governing equations were presented. Also, using a regression model, the mechanical parameters were predicted successfully using input parameters.

Self-compacting concrete with reduced formwork pressures

Self-compacting concrete (SCC) is normally characterized with high pressures exerted on the formwork during casting. The pressures can easily exceed bearing capacity of a regular formwork when casting a high structural member in one step. The contribution shows new ways of reducing the pressures using mineral additives based on calcinated clay minerals and clay nanoparticles whose addition together with interrupted casting process leads to a substantial reduction of the formwork pressures. Short interruptions in the casting lead to microstructural changes and flocculation, thixotropy and early strength evolution. The positive effects are studied systematically in microstructural studies performed on modified cement pastes using microscopy and viscosimetry. Rheological behavior of standard SCCs is improved towards thixotropy of the mixture by using the mineral additives. The newly developed recipes are tested on SCCs used on real construction sites. Examples of their practical utilization and on-site measurements show on up to 50 % pressure reductions in enriched SCCs compared to ordinary SCCs.

Improved slagging characteristics of low-value solid waste fuel asphalt rock by mineral additives of CaCO3, MgO, and Kaolin under fluidized bed condition

Improved slagging characteristics of low-value solid waste fuel asphalt rock by mineral additives of CaCO3, MgO, and Kaolin under fluidized bed condition

Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania

Abstract. Ocean alkalinity enhancement (OAE) aims to increase atmospheric CO2 sequestration in the oceans through the acceleration of chemical rock weathering. This could be achieved by grinding rocks containing alkaline minerals and adding the rock powder to the surface ocean where it dissolves and chemically locks CO2 in seawater as bicarbonate. However, CO2 sequestration during dissolution coincides with the release of potentially bioactive chemicals and may induce side effects. Here, we used 53 L microcosms to test how coastal plankton communities from Tasmania respond to OAE with olivine (mainly Mg2SiO4) or steel slag (mainly CaO and Ca(OH)2) as alkalinity sources. Three microcosms were left unperturbed and served as a control, three were enriched with olivine powder (1.9 g L−1), and three were enriched with steel slag powder (0.038 g L−1). Olivine and steel slag powders were of similar grain size. Olivine was added in a higher amount than the steel slag with the aim of compensating for the lower efficiency of olivine to deliver alkalinity over the 3-week experiment. Phytoplankton and zooplankton community responses as well as some biogeochemical parameters were monitored. Olivine and steel slag additions increased total alkalinity by 29 and 361 µmol kg−1, respectively, corresponding to a respective theoretical increase of 0.9 % and 14.8 % of the seawater storage capacity for atmospheric CO2. Olivine and steel slag released silicate nutrients into the seawater, but steel slag released considerably more and also significant amounts of phosphate. After 21 d, no significant difference was found in dissolved iron concentrations (>100 nmol L−1) in the treatments and the control. The slag addition increased dissolved manganese concentrations (771 nmol L−1), while olivine increased dissolved nickel concentrations (37 nmol L−1). There was no significant difference in total chlorophyll-a concentrations between the treatments and the control, likely due to nitrogen limitation of the phytoplankton community. However, flow cytometry results indicated an increase in the cellular abundance of several smaller (∼<20 µm) phytoplankton groups in the olivine treatment. The abundance of larger phytoplankton (∼>20 µm) decreased much more in the control than in the treatments after day 10. Furthermore, the maximum quantum yields of photosystem II (Fv/Fm) were higher in slag and olivine treatments, suggesting that mineral additions increased photosynthetic performance. The zooplankton community composition was also affected, with the most notable changes being observed in the dinoflagellate Noctiluca scintillans and the appendicularian Oikopleura sp. in the olivine treatment. Overall, the steel slag used here was more efficient for CO2 removal with OAE than the olivine over the 3-week timescale of the experiment. Furthermore, the steel slag appeared to induce less change in the plankton community than the olivine when comparing the CO2 removal potential of both minerals with the level of environmental impact that they caused.

EXPLORATION AND COMPARISON BETWEEN REGULAR CONCRETE AND CONCRETE WITH MINERAL ADDITIVES

Concrete is a fundamental building material with critical properties such as durability, strength, and versatility. In recent years, there has been increasing interest in enhancing concrete performance and sustainability by incorporating mineral additives such as fly ash, slag, and silica fume. This study explores and compares the characteristics of regular concrete and concrete with mineral additives to evaluate their suitability for various construction applications. The research focuses on the mechanical properties, durability, and environmental impacts of both types of concrete. Laboratory tests will be conducted to compare the compressive strength, tensile strength, resistance to freeze-thaw cycles, chemical attacks, and workability of regular concrete and concrete with mineral additives. Additionally, life cycle assessments will be performed to analyze the environmental implications of using mineral additives in concrete production. One of the main advantages of mineral additives is their potential to improve the strength and durability of concrete. Fly ash, slag, and silica fume have been shown to enhance long-term strength, reduce permeability, and increase resistance to chemical attacks in concrete mixtures. Furthermore, using mineral additives can reduce the reliance on cement, a primary component of concrete with a significant carbon footprint, leading to reduced greenhouse gas emissions and resource depletion. Index Terms – Concrete, Mineral additives, Durability, Strength.

Mechanical Behavior and Durability of Perlite Based Mortar Exposed to Sodium Sulfate Attack

The objective of this study is to gather additional on the impact of perlite on both the mechanical properties and resistance to chemical attacks of materials. Various combinations ,incorporating perlite in the form of cement additions, were examined. Five different substitution rates of 10 %, 15 %, 20 %, 25 %,and 30 % of cement with powder perlite were utilized for comparison with plain cement. The findings indicate that the interaction between lime,silica,and alumina in powder perlite results in the formation of several hydrates, such as calcium silicate hydrate, hydrated calcium aluminates,and hydrated gelhenite.Our research focuses on the development of natural perlite from maghnia as a potentially pozzolanic supplementary cementing material. In evaluating the pozzolanicity of this material, it was observed that external aggressions, such as chlorides, CO2, and chemical attacks, can compromise the physical and mechanical properties of concrete,affecting its long-term durability. However,natural pozzolans like pelite exhibit a positive influence on the durability of mortars against sulphate attacks. Test results revealed specimens with no apparent degradation, indicating that sulphate ions in the solution did not adversely affect perlite-based mortars. There is a growing preference for mineral additives with lower production costs than cement. Consequently, the optimal mixture was determined to be one containing 25 % perlite. However, cement pastes and mortars incorporating up to 20 % perlite demonstrated satisfactory physical and mechanical properties, comparable to materials without perlite. The investigation into the perlite materials used in conjunction with cement suggests the potential for sustainable concrete. Experimental results indicate that natural perlite powder from Maghnia can be considered a good pozzolanic material, suitable as a mineral admixture in cement production.

WITHDRAWN: An Investigation of a Hybrid Solar-Mineral Disinfection Technique Using Zeolite and Dead Sea Clay

Effluents from water treatment plants (WTP) can often contain a complex mixture of residual micro-contaminants and organisms, not removed during wastewater treatment. A combined trickling filter, activated sludge treatment, ozonation, membrane filtration, and suspended biofilm reactors have been shown to reduce these contaminants in waste effluent but at high capita cost. This study examined an inexpensive method of purifying water, which combines solar water disinfection with natural mineral clays (SOMIN-DIS). The study involved the addition of two types of mineral clays, Zeolite and Dead Sea minerals, to containers of polluted wastewater, at varying concentrations. The containers were then subjected to different durations of sunlight exposure. Then, samples were taken from all of the containers to quantify the overall numbers of Total Coliform, Pseudomonas aeruginosa (P.aeruginosa), and Escherichia coli (E.coli), utilizing the IDEXX system. The findings indicated that incorporating Dead Sea clay and Zeolite into SODIS-treated wastewater decreased the overall number of harmful microorganisms and shortened the disinfection duration, as compared to using natural minerals and solar water disinfection (SODIS) independently. Additionally, the study determined that the most effective concentration of Dead Sea minerals, resulting in the least amounts of harmful microorganisms and shortest purification duration, was 0.001g/ml. In contrast, the optimum concentration of Zeolite was 0.002g/ml. In general, the addition of Dead Sea and Zeolite minerals to the wastewater increased the inactivation of bacteria under SODIS from 40% to 65%.

Compressive Strength Analysis of Mortar Made from Volcanic Sand in Nagari Aia Angek Based on Magnetic Mineral Content

Mortar is a binder or adhesive with a standard viscosity of ingredients (water, cement, and sand). Mortar made has strength, mortar strength is measured using Cement Compression testing machine. Sand in mortar making contains magnetic minerals such as magnetite (Fe3O4) or Fe2+3Fe+2O4-2, hematite mineral (α-Fe2O3) which will be measured for magnetic susceptibility value using Bartington Magnetic Susceptibility Meter Sensor Type B (MS2B). To determine the concentration of magnetic minerals and their relationship with mortar compressive strength, the rock magnetism method was used. Measurement of sand samples of Kamumuan River, Sungai Limau District using Bartington Magnetic Susceptibility Meter Sensor Type B (MS2B) by categorizing sand into 3 treatment, namely Addition of magnetic minerals (PTM) with χLF value 3863.3 x 10-8m3/kg and χFD (%) 0.72, reduction of magnetic minerals (PKM) with χLF value 1920 x 10-8m3/kg and χFD (%) 0.79, normal magnetic minerals (PM) with χLF value 2334.7 x 10-8m3/kg and χFD (%) 0.62. The sample has a grain type that is almost no superparamagnetic grain and has antiferromagnetic properties. Samples grouped by treatment were made into mortar and tested using a cement compression testing machine with the results of mortar compressive strength, namely ATM of 49.4 Kg/cm², AKM of 46.6 Kg/cm², and AM 52.3 Kg/cm². Based on the analysis conducted, the magnetic minerals contained in the sand affect the results of the compressive strength of the mortar, the higher the susceptibility value in the sand, the stronger the compressive strength of the mortar

ANOVA-guided assessment of waste glass and limestone powder influence on ultra-high-performance concrete properties

Ultra-high-performance concrete (UHPC) possesses remarkable structural and durability characteristics, yet its widespread acceptance is hindered by cost inefficiency and environmental concerns. To address these challenges, this study investigates the impact of waste glass and limestone powder as partial substitutes for silica fume and cement in UHPC. For this, three distinct formulations are studied (Control, Optimized-1, and Optimized-2), representing different dosages of waste glass and limestone powder. The research focuses on six critical properties (compressive strength, modulus of elasticity, ultrasonic pulse velocity, initial surface absorption, density absorption, voids, and chloride ion penetration) evaluated at different ages (1, 7, 28, and 90 days for compressive strength, and 7, 28, and 90 days for the remaining properties). So, a total of 171 test specimens were examined, with 3 samples for each age and formulation. Statistical analysis, using ANOVA, assessed and confirmed the significance of the factors in the experimental results. The findings provide comprehensive insights into the UHPC formulations, highlighting the influence of waste glass and limestone powder on specified properties over varying ages. The research reveals that, despite the optimized blends exhibiting lower compressive strength values, all mixes surpass the 150 MPa threshold for cylindrical samples at the 90-day mark. Moreover, the Control mix consistently outperforms the optimized blends in modulus of elasticity at all ages, meeting ACI 239 criteria. The void content analysis shows encouraging trends, with all formulations displaying voids of less than 5% on the seventh day, improving during the curing process. Notably, Optimized-2 demonstrates superior performance over the Control mix after 90 days. Chloride ion penetration is minimal for all blends after 90 days, confirming the effectiveness of mineral admixtures. ANOVA analysis confirms significant impacts of formulation and age on various UHPC characteristics, emphasizing the consistent reduction in performance with alternative mineral additions. The interaction between formulation and age implies variations in property evolution, suggesting potential convergence with alternative formulations.

Growth of Vannamei Shrimp (Litopeneaus vannamei) in Rearing Media with Different Salinities

The addition of calcium, phosphorus and magnesium minerals has been carried out separately in vannamei shrimp cultivation activities using fresh water media. Furthermore, the combination of the three types of potassium is expected to mutually fulfill the mineral needs of vannamei shrimp so that their growth becomes more optimal. This research aims to analyze the growth of vannamei shrimp reared in various media with different mineral levels. The treatments in this study were P1 (30 ppt), P2 (20 ppt), P3 (10 ppt), P4 (0 ppt without the addition of minerals), and P5 (0 ppt with the addition of various types of mineral sources). The research results show that the best SGR weight is found in P1 at 12.42%/day. The highest SR value was also obtained at P1, namely 65%. The SR and SGR values at P5 are higher than at P4, but still lower than at P1, P2, and P3. Based on these results, it is known that the growth of vannamei shrimp reared in fresh water media with added minerals has increased compared to vannamei shrimp reared in fresh water media without added minerals, but is still lower compared to the growth of vannamei shrimp reared in water media. sea. Furthermore, research is needed on adding other types of minerals to low salinity vannamei shrimp cultivation media.

Use of lupine with bischofite in feeding of broiler chickens

Currently, feed and mineral substances of non-traditional origin are widely used in feeding animals and poultry. The effectiveness of using new mineral complexes and non-traditional feed ingredients is constantly being studied. In this regard, the study of mineral additives and non-traditional feeds, as well as the eff ectiveness of their use in feeding animals and poultry is an urgent problem. The purpose of the work was to study the use of lupine together with bischofite in feeding of broiler chickens. In order to achieve the purpose of research two scientific and economic experiments were carried out on broiler chickens of the cross Ross 308 to study the infl uence of an alternative feed protein (lupine variety Deco) and a natural mineral additive (bischofi te) on the quality of the resulting products. The duration of each scientific and economic experiment was 37 days. It was found in the results of the first scientific and economic experiment that the use of lupine of the variety Deco and the natural mineral additive bischofite in the diets of broiler chickens in the feed composition made it possible to obtain additional profi t in the amount of 197,64–1345,38 rubles per 120 heads of broilers. The level of profi tability in the 1st experimental group of broiler chickens was higher by 1,01 abs.%, in the 2nd experimental group by 6,72 abs.% and in the 3rd experimental group by 4,03 abs.% compared to the control group. In the control group this figure was 19,77 %. It was established in the results of the second scientific and economic experiment that the use of variety lupine Deco and the natural mineral additive bischofi te in the diets of broiler chickens contributed to additional profi t in the amount of 1171,51 rubles per on 120 heads of broilers. The level of profitability in the experimental group was higher by 5,56 abs.% compared to the control group.

The Use of Sargassum spp. Ashes Like a Raw Material for Mortar Production: Composite Performance and Environmental Outlook.

The accumulation of brown algae from the genus Sargassum has been increasing over the years in coastal regions of the Caribbean, Africa, Brazil, and Mexico. This causes harmful effects to the ecosystem, human health, the economy, and the climate due to gas emissions from its decomposition process. There is the possibility of this biomass being reused in civil construction, and some studies have been carried out on its application to common Portland cement mortar. As such, the objective of this study is to evaluate the potential of sargassum ash as a mineral addition to partially replace fine aggregates in Portland cement mortar. Characterization of the raw materials was carried out through X-ray fluorescence spectroscopy, loss on ignition, particle size distribution, Brunauer-Emmett-Teller (BET) analysis, real density, X-ray diffraction, scanning electron microscopy, and dispersion spectroscopy of electrons. The mortars were prepared by partially replacing the fine aggregate (sand) with sargassum ash at 0%, 5%, 10%, and 20%. Mortar performance was evaluated through water absorption, apparent porosity, apparent specific mass, and compressive strength 7, 28, and 63 days after curing. Lastly, a life cycle assessment was conducted in accordance with ISO standards 14040:2006 and 14044:2006. The results showed that replacing sand with sargassum ash increases water absorption and apparent porosity, and decreases the apparent specific mass and compressive strength as replacement increases. Nevertheless, the compressive strength results after 63 days for 5 and 10% replacement did not differ statistically from reference values. The life cycle assessment indicated that mortars with partial replacement of sand by sargassum ash show positive environmental impacts when compared to reference values for most categories, regardless of the scenario analyzed, especially for mortar with 10% replacement. As such, the use of sargassum ash at 10% does not alter the mortar's compressive strength values after 63 days, but does reduce its environmental impact. The application of this biomass in civil construction materials provides a destination for this algae, and that can be a solution to mitigate the social, environmental, and economic problems it has been causing.

The Influence of the Matrix Grain Size and Mineral Addition on Improving the Knock-Out Properties of Molding Sands with an Inorganic Binder

This article presents the results of tests of molding and core sands with inorganic binders incorporating a mineral in the form of raw perlite ore. This material serves to reduce the final strength, thereby improving the knock-out properties. The assumption was made that the selection of the optimal fraction of the loosening additive, tailored to the grain size of the matrix of the molding sand used in foundries, could significantly affect its mechanical and technological parameters. The tests were conducted on molding sands prepared using three quartz sands with the addition of perlite ore of different grain sizes. In addition to determining the final tensile strength, the permeability and grindability of the molding sands were assessed. The results indicated that the raw perlite ore significantly reduced the final strength of the molding sands in each considered system, with the best efficiency achieved when using finer fractions. Moreover, the mineral’s addition had a minor impact on the technological properties of the molding sands, such as permeability and grindability.

Experimental and Numerical Investigations of the Effect of Curing Conditions on the Temperature Rise of Concrete

This paper presents experimental and numerical studies investigating the impact of three curing conditions on temperature evolution in concrete cubes. The tests were performed on samples of the same volume (3.375 dm3) under different curing conditions: room temperature, insulation boxes, and adiabatic calorimeter. Various cements (Portland cement, Portland composite cement, and blast furnace slag cement) and aggregates (gravel and basalt) were examined. The temperature evolution for all mixtures was analyzed, revealing a correlation between temperature increase and concrete type. Under insulation and adiabatic curing, Portland cement with gravel aggregate exhibited the highest temperature rise, while blast furnace slag cement with basalt aggregate showed the lowest increase. The incorporation of slag, ash, or other mineral additives reduced temperature rise. Additionally, basalt aggregate’s higher heat capacity and thermal energy accumulation led to a decreased temperature increase compared to gravel. Using recorded thermal data, a numerical procedure predicting temperature development in nonadiabatic conditions through direct adiabatic tests is proposed. Comparisons between experimental and numerical temperature evolutions confirmed the model’s accuracy.

The influence of selected mineral ingredients on the technological properties of sealing slurries

Sealing slurries used to modify the subsoil should meet a number of requirements, including: rheological properties, setting time, appropriate mechanical strength and durability. The study determined the technological properties of sealing slurries prepared with ordinary Portland cement and blended binders containing appropriately selected mineral additives. The tests used granulated blast furnace slag, silica fly ash and ash obtained in the fluidized bed combustion of coal. The assessment of the technological properties of fresh slurries included the selection of an appropriate rheological model and the assessment of the rheological properties of the sealing slurry, such as: plastic viscosity, apparent viscosity and yield point. The research determined the factors causing improvement of the technological properties of fresh slurry. The use of supplementary cementitious materials, also in systems with fluidizing admixtures, allowed for a significant modification of the rheology of the tested sealing slurries. The obtained results indicate their beneficial effect on the functional properties of slurries, enabling their use as binder components replacing Portland cement, while limiting or even eliminating the addition of superplasticizers.

Energy-Efficient Mixtures Suitable for 3D Technologies

Compositions of fine-grained concrete mixtures that provide the minimum required strength values in 1 day (7.5 MPa) have been developed. A comparison was made of the test results of the properties of samples printed on a 3D printer with samples made according to the same recipes on a vibrating platform. A laboratory printer was designed and constructed to study the properties of extruded mixtures. The method was also proposed for measuring concrete mixes’ structural strength. Analysis of experimental data allowed the establishment of the features of the influence of the mineral additives and slag–alkaline binders for a comparison of basic physical and mechanical properties of concretes for 3D printing. It has been experimentally shown that possible undercompaction of the fine-grained mixtures formed on a 3D printer and decrease of properties are compensated by the introduction of hardening activator and superplasticizer additives. The novelty of this work lies in determining the comparative effect of various products of technogenic origin on the properties of mixtures for 3D printing.