Production Of High Strength Concrete Research Articles

Synergistic effect of recycling waste coconut shell ash, metakaolin, and calcined clay as supplementary cementitious material on hardened properties and embodied carbon of high strength concrete

Researchers are investigating eco-friendly binders like coconut shell ash (CSA), metakaolin (MK), and calcined clay (CC) as supplementary cementitious materials (SCM) in high-strength concrete (HSC). Abundantly available as industrial or agricultural waste, these materials, when combined with Portland cement (PC), offer synergistic benefits. This not only improves concrete performance but also addresses waste disposal issues, presenting a sustainable and environmentally friendly solution for long-term use in HSC production. However, this study performed on fresh and mechanical characteristics of HSC blended with CSA, MK, and CCA alone and together as SCM after 28 days of curing. A total of 504 samples of standard concrete were cast and the cubical samples were tested to achieve the targeted compressive strength about 80 MPa after 28 days. The experimental results indicated that the rise in tensile, flexural and compressive strengths of 9.62%, 8.27%, and 10.71% at 9% of CSA, MK, and CC as SCM after 28 days of curing. As SCM content increases, the density, porosity and water absorption of concrete decrease. Moreover, the workability of fresh concrete is getting reduced when the concentration of SCMs increases in HSC. In addition, the concrete's sustainability assessment revealed that employing 18% MK, CC, and CSA as SCM reduced carbon emissions by approximately 11.78%. It is suggested that using 9% CC, MK and CSA together in HSC yields the best results for practical applications in civil engineering.

Using the surface energy of nanoparticles to produce high-strength concrete

The article considers a method for activating cement hardening processes using nanomaterials due to the magnitude of their surface energy: when injected into concrete, nanoparticles dump it due to the desire to transition to a stable state. Such activity leads to a significant gain in strength, hardness and the production of high-strength concrete. It is shown that such an effect can be achieved by surface impregnation of concrete with sols (colloidal solutions) based on SiO2 nanoparticles. It is advisable to start impregnation from the third day of hardening under normal conditions. At this age, the main heat of the cement's own exothermic hardening reaction has already been released into the environment, and the introduction of additional energy will not cause a shift in equilibrium towards slowing down the hardening processes in accordance with the Le-Chatelier principle. The results of physico-chemical studies of concrete after hardening, explaining this effect, are presented.

Suitability of marble powders in production of high strength concrete

A tremendous amount of non-biodegradable waste is created during mining and processing tasks of layered stones like marble. Over time, this has become a global problem because it harms the environment in multiple ways. Hence, it is necessary to find an alternate way to securely dispose and reuse marble wastes. The construction sector is one of the significant consumers of natural resources for the production of material binders and aggregates. As a result, in recent years, number of researchers have carried out studies in which various kinds of marble waste have been incorporated into concrete with the intention of substituting either cement or aggregates or both. This paper presents the effect of two locally sourced waste marble powders Kadapa marble powder (KMP) and Bethamcherla marble powder (BMP) as partial replacement of cement on mechanical and durability properties of high strength concrete (HSC). Their effect at different replacement levels in HSC is evaluated in compressive, indirect tensile and flexural strengths, elastic modulus, chloride penetration resistance and freeze–thaw durability properties. Micro-structural investigation is also conducted to evaluate their impact on the matrix of HSC containing waste marble powders as additional cementitious materials. Results show that the HSC consisting of KMP and BMP content of 10% and 15%, respectively exhibited higher mechanical and durability properties than the control HSC. Micro-structural investigation also supports this finding. It can be concluded that the use of marble powders as partial replacement of cement does not have any adverse impact on the properties of concrete. The use of KMP and BMP reduces the vast amount of energy required to produce cement, cost and time with reduction in environmental hazards.

Experimental Analysis of High-Strength Concrete Using Granite Aggregates

The present study investigates the effect of incorporating metakaolin and silica fumes in the production of high-strength concrete along with partial replacement of coarse granite aggregates in the high-strength concrete. The higher compressive strength, refined microstructure, and decreased permeability of high-strength concrete are some of the properties responsible for its trending use in the modern construction industry. The main purpose of this research is to evaluate the effect of the replacement of coarse granite aggregates with natural aggregates on the mechanical and durability properties of high-strength concrete. For understanding the effect of metakaolin, silica fume, and granite aggregates on the properties of high-strength concrete, various specimens such as cubes, cylinders, and cylindrical discs were cast and tested after 7, 14, and 28 days of curing. Various concrete mixes were prepared by adding silica fume at 5%, 7.5%, and 10% and metakaolin at 5%, 7.5%, 10%, 12.5%, and 15% in concrete production. Furthermore, High-strength concrete mixes were also prepared by replacing natural coarse aggregates with granite coarse aggregates by 25%, 50%, 75%, and 100% to study the effect of replacement percentage on the concrete properties. Test results indicated that the compressive strength and split tensile strength of the concrete mix increased with the increase in the replacement percentage of granite aggregates, with the highest strength seen at complete replacement with granite aggregate due to the enhanced compressive strength of such aggregates in comparison with the natural coarse aggregates. In various mixes cast using metakaolin and silica fume, the highest compressive strength was seen in a mix containing 10% metakaolin and 7.5% silica fume, and results of other mixes indicated that the use of silica fume and metakaolin are viable options for high-strength concrete production in our experimental study.

A Review on Enhancing Quality of Self-Compacting Concrete by Used Cement Plastic Bag

Abstract: Plastic waste is a vital solid waste due to its un-decaying properties with respect to time, but plastic waste has interlocking properties that lead to enhancing the interlocking properties of the concrete. Self-compacting concrete is concrete with high workability and does not need vibration it is good for complex structural elements. So high-strength concrete production becomes typical but the interlocking properties of the plastic waste can be given a suitable direction for the strength parameter of self-compacting concrete. The major plastic waste source at the site is the cement plastic bags, cement bags are made of polypropylene polymer therefore they cannot react with cement, but are fibrous in nature and perform good interlocking properties.

Optimization of partial replacement of cement by silica fume and rice husk ash for sustainable concrete

The reuse of cementitious materials of agricultural and industrial origin in concrete has been accepted as an environmentally friendly solution. Although many newer materials are being introduced, their potential to replace cement either partially or completely depends heavily on the parent material influence (PMI). Optimization of mix proportioning and suitability for different applications are critical factors in establishing a sustainable business model with positive environmental impact. The present study addresses the application of a ternary combination of rice husk ash (RHA) and silica fume (SF) as pozzolone material for the development of composite cements. The experimental results on strength, chloride ion permeability and corrosion resistance of mixed cement concretes show that the selected combination of materials is suitable for the production of high strength concretes. The optimum combination for simultaneous replacement is 5 % RHA and 2.5 % SF, to obtain the selected strength properties. Moreover, the results of the mixture of OPC + 10 % RHA have achieved high compressive strength compared to the other mixtures.

Characteristics of High-Strength Concrete Reinforced with Steel Fibers Recovered from Waste Tires

A large quantum of vehicle waste is produced annually, of which tires pose the topmost hazard to the planet if not disposed of duly. only in Egypt, the approximately total number of tires generated annually could be about 10 million tires. Demand for tires is expected to increase each year, and in emerging economies, rising profits may increase the vehicles used and drive greater demand for tires. In 2017, approximately 287 million synthetic tires were produced in the United States and approximately 60 million tires were stored in warehouses . The disposal of those tires in landfills when they attain their end life and turn to waste is one of the essential difficult troubles inflicting numerous environmental problems . Therefore, some countries have passed laws to ban landfilling of tires and encourage the reuse of used tires for other purposes . Fiber Reinforced Concrete is a composite material composed primarily of concrete or mortar and randomly distributed with short, discontinuous, distinct fine fibers of defined geometry . The main fibers used in concrete include glass, rubber, steel, aramid and other synthetic fibers. The effectiveness of fiber-reinforced concrete depends on the nature and geometry of the fibers . One possible solution to recover waste steel fibers from the tire manufacturing process is to add them to concrete . In terms of various initiatives around the world to convert waste into new products, the purpose of this article is to quantify the steel fiber contribution of recycled tires used in the production of high-strength concrete. Steel fibers in recycled tires are extracted through mechanical recycling from used tires. In this process, rubber is crushed and granulated, iron is removed with a magnet, and cloth is removed with a vacuum. As a result, recycled tiers steel fibers are irregular in shape and come in a variety of lengths and diameters, but are highly resistant to bending because they are made of high-quality steel.. Recycled steel fibers can be used as cement reinforcing additives or reused as reclaimed steel. . However, fibers extracted from tires are contaminated with rubber particles (15-60% by weight), making them difficult to use directly for any purposeand a cleaning process is required. Also, due to its low density, it is expensive to transport. As a result, these textile fibers are often sent to landfills or incinerators. Adding steel fibers or other fibers to concrete can not only improve the toughness and ductility of concrete, but also improve the crack resistance and durability of concrete . Adding steel fibers to concrete can improve the concrete's deformation properties. Cracks in concrete develop slowly and the crack width is smaller than that of normal concrete. Concrete mixtures containing steel balls recovered from scrap tires had higher workability at less than 4%, and no significant decrease in compressive strength was observed at less than 2%. Although the effect of steel fibers on the compressive strength of concrete is negligible, the tensile and bending strengths increase significantly, but the resistance decreases when the fibers are mixed in an optimal ratio and increase slightly. There have been many studies on the use of waste tire steel fibers in conventional concrete. However, more research is needed on the effect of steel fibers from waste tires on high-strength concrete. In this study, the effect of steel fibers extracted from tires on high-strength concrete was investigated.

Study on Experimental Behavior of Plastic Based Fiber as Secondary Reinforcement in Concrete Pavement

Abstract: Nowadays, the use of fibers of various materials such as polyethylene, polyester and polymer in concrete has increased extensively as reinforcement supplement material for production of high strength concrete. The incorporation of these material in concrete not only helps in improvement of desired properties of concrete but also helps in the mitigation of disposal issue of such non-biodegradable substances. Various such materials like plastics, different grades of single use polyethylene and rubber tyres cause environmental pollution which leads to environmental and health problems. Many of these can be used as supplement to reinforce the concrete such as PET and polyethylene in fibre form. In this paper the author has studied the effect of addition of mix of different proportion of polyethylene fibre (milk packet), PET (plastic bottle) and Recron 3S as replacement of fine aggregate on concrete properties such as compressive strength, flexural strength, split tensile strength, workability. The proportions of the mixtures used were based on the dry volume of cement (0%, 0.2%, 0.4% and 0.6%).

New approach for the mix design of high-strength concretes valorization of local aggregates

Purpose The purpose of this paper is to make a contribution to understanding the influence of factors such as the water/cement (W/C) ratio and the granular class on the mechanical and physical properties of high-strength concretes (HSCs). In the formulations of HSC, aggregates by their high mass and volume proportion play an important role. When selecting aggregates, it is necessary to know their intrinsic properties. These properties influence the performance of concrete, in particular the quality of the granulate cimentary adhesion. Design/methodology/approach This experimental study focused on the effect of W/C ratio (0.25, 0.30, 0.35), the effect of replacing a part of cement by silica fume (SF) (8%), the effect of fraction of aggregate on properties of fresh and hardened concrete, the effect of different environment conversation like drinking water and sea water on compressive strength and the study of absorption of water and softening using the mix design method of the University of Sherbrooke combined with the Dreux-Gorisse method which gives good results. Findings At the end of our work, the examination of the results obtained made it possible to establish the correlations between the formulations studied and the physicomechanical characteristics of the concrete compositions (HSC25, HSC16, HSC8). The results of this study show that the use of three granular classifications (DMAX8, DMAX16 and DMAX25) and three report W/C (0.25, 0.30 and 0.35) in two different conservation environment (drinking water and sea water) give HSCs, HSC25 with an W/C = 0.25 ratio has reached the largest mechanical strength of 90 MPa for different environments of conservation. For selecting aggregates, it is necessary to know their intrinsic properties, these properties influence the strength of concrete. In general, there is a slight decrease in the compressive resistance of the specimens stored in seawater, it can be said that the conservation life has not had effect on the resistance (28 days). The effect of aggressive environment can appear in the long term. Research limitations/implications Mixed design and concrete fabrication with a 28-day compressive strength of up to 68 MPa or more of 90 MPa can now be possible used in Jiel (Algeria), and it should no longer be considered to be used only in an experimental domain. Addition of SF in concrete showed good development of strength between 7 and 28 days, depending on the design of the mix. Practical implications Concrete containing 8% SF with W/B of 0.25 has higher compressive strength than the other concretes, and concretes with SF are more resistant than concretes without SF, so it is possible to have concrete with a compressive strength of 82 MPa for W/C 0.25 without SF. Like as a result, we can avoid the use of SF to affect the strength of concrete at compressive strength of 68 MPa, and a slump of 21 cm, because the SF is the most expensive ingredient used in the composition of concrete and is therefore very important economically. One of the main factors of production of HSC above 90 MPa is use of aggregate DMAX25, which is stronger with W/B of 0.25 and 0.30. Social implications This mixtures leads to a very dense microstructure and low porosity and produces increased permeability of HSC and is able to resist the penetration of aggressive agents. This combination has a positive effect on the economy of concrete. Originality/value The combination of the Dreux-Gorisse method with the Sherbrook method is very beneficial for determining the percentage of aggregates used, and the use of coarse aggregates of Jijel to obtain HSC with 90 MPa and 16 cm of workability.

ANALYSIS OF THE MICROSTRUCTURE OF CONCRETE FRACTURES IN STRUCTURES THAT WORK ON COMPRESSION AND ITS IMPACT ON STRENGTH

Comparative microanalysis and elemental analysis of the structure of chips of concrete composites of different strength from compressive structures were used. Analysis of the microstructure of concrete chips was performed using a scanning electron microscope from Oxford SU 70 using a CCD detector. Elemental analysis of objects was performed using energy-dispersive X-wave spectroscopy (EDC analysis). The method of energy-dispersive X-wave spectroscopy is used. The character of opening of cracks of concrete samples in the course of their destruction is analyzed. From the data of X-ray and spectral analysis it follows that in a series of samples of strength of 120 MPa in the process of hydration of clinker minerals during hardening of concrete a number of chemically active substances is formed. These are primarily potassium oxide hydrate, calcium silicate hydrate (HSC) and structural gel models such as Janite and Tobermorite. Modification of the concrete composite with a complex of MK and MTK create conditions for the conversion of unstable and soluble calcium hydroxide into a strong crystalline hydrate of calcium silicate. The structure of concrete compacted in this form gives a significant increase in strength. The influence of ultrafine modifiers on the microstructure of cement stone formed during the operation of the structure and the strength of concrete are determined. The results of the scanning electron microscopy analysis show that the phase sizes differ slightly, but are not larger than ≈20 μm. Characteristic destruction of the sample with a strength of 120 MPa occurred in the main cracks, which develop due to the greater number of phases in contrast to the nature of the destruction of the sample with a strength of 50 MPa, which broke mainly on one structure. The complex of modifiers based on microsilica and metakaolin in the concrete mixture creates conditions for the conversion of unstable and soluble calcium hydroxide into a strong crystalline hydrate of calcium silicate. When using cement with a low content of C3S less than ≈50% significantly complicates the production of high-strength concretes, in particular when using silica and metakaolin, because the effectiveness of these additives implies the presence of excess portlandite Ca (OH)2 in the curing system, while systems with low C3S content is characterized by a reduced content of Ca (OH)2.

Influences of high-volume coal bottom ash as cement and fine aggregate replacements on strength and heat evolution of eco-friendly high-strength concrete

This study investigates the potential of using high-volume bottom ash as a supplementary cementitious material (SCM) and fine aggregate replacement in production of high-strength concrete. In the first stage, bottom ash quality was improved by sieving through a No. 50 sieve and grinding to increase fineness. Ground bottom ash (GBA) replaced ordinary Portland cement (OPC) at 35%, 50%, and 65% by weight to produce high-strength concrete. In the second stage, coarse bottom ash (CBA) retained by a No. 50 sieve replaced fine aggregate in an optimum mixture at 20%, 40%, and 60% by volume. Concrete properties including compressive strength, modulus of elasticity, autogenous shrinkage, and heat evolution were evaluated. The economic and environmental impacts of GBA were assessed. The results indicated that concrete with 50% GBA cement replacement could be classified as high-strength concrete at 7 d, achieving a compressive strength of approximately 80.9 MPa at 28 d. Autogenous shrinkage was decreased with an increase in GBA content. The heat evolution of concrete with 50% GBA was decreased by 36.4% compared with the control concrete. Concrete with 50% GBA cement replacement and 60% CBA fine aggregate replacement demonstrated the greatest reduction in autogenous shrinkage and peak of heat evolution, and it was classified as high-strength concrete.

Conceptual Framework for Optimizing the Dispersed Composition of Cement Systems

The disadvantage of high-strength multicomponent concretes is the high absolute and specific consumption of the binder per unit of strength. The object of research is multicomponent cement systems. The subject is the composition of multicomponent cement systems in order to significantly increase the concentration of the solid phase per unit volume, as well as strength and durability. The creation of a dense, highly filled solid phase in the form of heterogeneous mineral modifiers of a homogeneous dispersed structure ensures the production of high strength concretes with a low binder content. Theoretical and practical studies have shown that there are only three levels of dispersion of mineral modifiers, functionally related to the spatial and geometric parameters of the clinker component and its own pozzolanic activity, providing strength and other construction and technical properties of multicomponent cement systems at the maximum level. The properties and structure of concrete were studied using two fractions of fine aggregate, granite-gabro crushed stone fr. 5-10 mm, Portland cement class CEM I 42.5N, finely dispersed blast-furnace granular slag, microsilica, highly dispersed fraction of cement, superplasticizer Glenium 430 and high-valence hardening accelerator. Research methods: the shape and size of dispersed particles of the components were determined by a laser analyzer, the mobility of the concrete mixture in accordance with GOST 10181–2014, the strength of concrete in accordance with GOST 10180–2012. The structure of the cement stone was studied using scanning microscopy, thermographic and X-ray phase analysis methods. The strength of concrete with an optimized disperse composition, a superplasticizer and a high-valence hardening accelerator at the age of 28 days after hardening under normal conditions was 128; 137; 163 MPa, with the consumption of multicomponent cement, respectively 650, 700, 750 kg / m3.

Investigation of the Use of Marble Powder in Production of High Strength Concretes

The first of the aims of this study is to determine the amount of marble powder to be used in the optimum amount for high strength concrete (YDB). The second is to contribute to reducing the use of natural resources by using marble powder from waste materials in the production of YDB. For this purpose, marble powder was used by replacing it with fine aggregate at 0-8-16-24% by weight. In order to increase the pozzolanic activity in concrete mixtures and to ensure maximum use of marble powder, silica fume has been used by replacing it with cement at 10% by weight. The slump test was applied to the obtained mixtures. Then fc-7., fc-28. and fc-90. days, it was kept in the curing pool to be subjected to the compressive strength test. According to the results obtained from the compressive strength test, the optimum amount of marble powder was determined by taking into account the high strength value. In addition, it is thought that the use of marble powder contributes positively to the compressive strength of concrete, consumption of natural resources and reduction of environmental pollution. Keywords: High strength concrete, marble powder, compressive strength, silica fume.

Fresh, Mechanical, and Microstructural Properties Investigation on the Combined Effect of Biomedical Waste Incinerator Ash and Bagasse Ash for High-Strength Concrete

The combination effect of supplementary cementitious materials in the production of high-strength concrete production is an effective way to reduce the amount of cement required while contributing to environmental sustainability and cost. This study aims to assess the microstructural investigation on the combined effect of biomedical waste incinerator ash (BWIA) and bagasse ash (BA) as a partial replacement of cement in high-strength concrete production. The cement was partially replaced with BA (0%, 2.5%, 5%, and 7.5%) and BWIA (0%, 2.5%, 5%, and 7.5%). The mix design was done as per the ACI 211-4R-93 mix design standard. Slump, slump flowability, density, and compaction factor tests were conducted for freshly mixed concrete. Mechanical properties of the hardened concrete from four different mixes were also determined for the 7- and 28-day cured specimens. The microstructural properties of the hardened concrete for all mixes were also investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests. Based on the experimental results, the compressive strength of high-strength concrete at every 2.5% BA and 2.5% BWIA replacement of cement in the concrete mix at 7 days of curing was slightly decreased, while at 28 days of curing, the compressive strength of the control mix (51.8 MPa) decreased as compared to the mix codes' compressive strength of the BWIA and BA5 and BWIA and BA10 mix codes, at 54.8 MPa and 52.5 MPa, respectively. The SEM micrographs showed that the partial replacement of cement by the BWIA and BA leads to a decrease in the pore proportion in the enlarged interfacial transition zone (ITZ), reduced CH crystals, and a denser C–S–H gel as compared to the control specimen. The XRD pattern showed the existence of portlandite, ettringite, okenite, quartz, and calcite in the cement and aggregate phases. As a result, the usage of BWIA and BA has a significant impact on the properties of high-strength concrete in fresh, hardened, and microstructure high-strength concrete.

Development of High-Strength Concrete Mixed Design System Using Artificial Intelligence

The quality inspection of high-strength concrete construction sites consists of a compressive strength test that is considered the most important, but this can be confirmed through a compressive strength test after 28 days of high-strength concrete application. Therefore, it is of paramount importance to ship high-quality products to ready-mixed concrete factories by increasing the reliability of the mixed design that affects high-strength concrete production. In addition, there is a need to develop an efficient management system for mixed design that determines high-strength concrete quality by measuring the mixing ratio of materials in the ready-mixed concrete factory production stage. This study used matrix laboratory(MATLAB) using Deep learning, a language that performs mathematics and engineering calculations based on matrices, and presented a mixed design model by adjusting the strength through input and output variables, learning data collection, model structure determination, learning error, and repetition results. The predicted mean value of 40 MPa was measured at 40.75 MPa, showing a difference of 0.75 MPa and 40 MPa, and the error rate was confirmed to be 4.13%. And the predicted mean value of 55 MPa was measured as 55.55 MPa, showing a difference between 55 MPa and 0.55 MPa, and the error rate was confirmed to be 1.73%. Through this study, the reliability of high-strength concrete quality management is secured by applying a high-strength concrete mixed design system using artificial intelligence(AI) and adjusting it in connection with all fields of the production process.

Study of High Strength Concretes with Variability of Composition Designs

High Strength Concretes (HSC) are concretes defined mainly by compressive strength. The strength of concrete can guarantee other excellent results of properties, namely durability. Essential for the production of HSC is a careful approach to the design of concrete composition, especially the quality of raw materials. It is primarily necessary to increase the content of the binder combined mainly with Portland cement and another admixture. Due to its excellent properties, Silica fume is largely used as an admixture, where it is necessary to consider its effective amount. It is also suitable to combine this admixture with other types of active admixtures. The question of the type of coarse aggregate fractions used is crucial. The quality and purity of aggregates is an essential part of the quality design of these concretes, influencing practically all the resulting parameters of concrete. The article presents a set of tests on designed High strength Concretes, differing in the composition of the concrete to demonstrate the variability of the design concept and its effect on the resulting values of strength and durability.

Structural Performance Assessment of High Strength Concrete Containing Spent Garnet under Three Point Bending Test

The utilization of river sand for miscellaneous construction purposes had directly increased due to rapid growth of construction industry. This fact caused over exploitation of riverbeds and troubled the eco-system. This study aims to find out the optimum percentage of spent garnet in high strength concrete and to forecast the structural performance of high strength concrete containing spent garnet with the previous research results. This study focusing on comparing and forecasting the utilization of 0%, 10%, 20%, 30% and 40% spent garnet as a sand replacement in high strength concrete at the age of 28 days. The level of 20% replacement of sand seen to be the optimum percentage of spent garnet for this concrete mixture to enhance its structure performance. It is concluded that, utilization of spent garnet in high strength concrete production able to reduce the dependency on river sand and lesser the waste from landfill.

Determining the optimum percentages of fly ash, metakaolin and copper slag by replacing cement and fine aggregate in m30 grade concrete

The overall production of the cement has greatly increased which results lots of problems in environment as it involves the emission of CO2   gas.  Environmental concerns, stemming from the high energy expense and carbon dioxide emission associated with cement manufacture have brought about pressures to reduce cement consumption through the use of supplementary materials. Materials such as Metakaolin, fly ash have good pozzolanic activity and are a good material for the production of high strength concrete. Copper slag is a by-product of copper extraction by smelting. Copper slag can be used in concrete production as a partial replacement for sand. However, it is expected that the use of Metakaolin, Fly ash and Copper slag in concrete improves the strength properties of concrete.
 Keywords: Supplementary cementitious material, Cement, Fine aggregate

On the Application of Diopside Rock of the Aldan Deposit in the Production of Concretes

The study on the possibility of heavy-weight concrete production using diopside aggregates from Aldanslyuda ore mining and processing plant has been conducted. It is established that diopside crushed stone, namely, the crushed stone mixture of fractions from 5 to 20 mm is suitable for concretes of strength class up to 60 MPa production. It is recommended to carry out further validating research on the application of diopside rocks in high-strength concrete production. To do that it is necessary to use river sand, the water demand of which is less than of the sand from sifting of crushing solid stone, as a fine aggregate or to replace part of the latter. The physical and mechanical properties of the concretes developed on the basis of diopside aggregates have been investigated.

Integrated mixing machine for sulfur concrete production

The production of sulfur concrete (SC) from its ingredient materials requires controlled heating and mixing conditions at a temperature level of 130°-150 °C. Although this process considered to be common and applicable at the industrial level, it is difficult at the laboratory/research level. This paper presents the design and manufacturing details of a relatively inexpensive laboratory machine for heating and mixing sulfur concrete. The different components of the machine are described in detail to help researchers to produce high-quality sulfur concrete. In this work, the quality of the machine is verified through experimental testing of the physical and mechanical properties of different prepared SC mixtures. Thus, the homogeneity and mixing efficiency required a certain level of workability, and the full controlling of temperature during the production process has been realized. The machine is proven to be efficient, safe, and durable. The comparative study on the physical and mechanical properties of the prepared SC relative to other SC of the same ingredients but heated and mixed through other small-scale machines, showed the superiority of the mixing machine in the production of high strength concrete.