Natural Sand Research Articles

Methodological approach based on life cycle assessment for upcycling leftover concrete into dry industrial mortars

This study examines the integration of Life Cycle Assessment (LCA) as a crucial decision-making tool in by-product recovery studies within the construction sector. Unlike conventional methods that often delay LCA until after thecnical studies, our approach places LCA at the forefront of decision-making, ensuring that environmental considerations guide material design.This study investigates the valorization of concrete return fines in dry-mix mortars, starting with an initial LCA to validate environmental benefits of substituting natural sand by recycled sand before testing various formulations with different substitution rate.Our findings reveal significant reduction mainly in natural resource depletion, particularly evident at a 55% substitution rate, suggesting complete independence from natural resources. Additionally, the ecological profitability threshold is established at 200 km, indicating the radius within which the recycled sand can be used without compromising environmental gains.Economically, Life Cycle Costing (LCC) analysis demonstrate the cost-effectiveness of using recycled sand, even when its price exceeds that of natural sand. This economic resilience allows for flexibility in setting the selling price of recycled sand, thereby enhancing its valuation.In conclusion, our approach represents a paradigm shift in ecological decision-making by priotirizing LCA to emphasize the balance between environmental benefits and economic viability. This study paves the way for an eco-friendly application with significant potential for adoption within the construction industry.

Study on sulfate diffusion test and mathematical model of manufactured sand concrete under typical freeze-thaw environment in Northwest China

In the construction industry, it is imperative to replace natural sand with manufactured sand. The environment in northwest China is very complex and harsh. The application of manufactured sand concrete in such a harsh environment needs scientific and comprehensive research to meet the requirements. However, there is a gap in the study of sulfate freeze-thaw resistance of manufactured sand concrete in the complex environment of Northwest China. Therefore, this study investigated the northwest environment, designed an indoor sulfate freeze-thaw cycle experiment system close to the real environment, and designed a conductive titration method to test the sulfate ion content in hardened concrete. The influence of the freeze-thaw cycle on the diffusion depth of sulfate ions in manufactured sand concrete was studied. Finally, the following conclusions are obtained: In the process of conductometric titration, hydrochloric acid is used as the dissolution solution, Ag2O and CO2 are used as neutralizers, and Ba(NO3)2 is used as the titration solution, which can perfectly eliminate the significant influence ions in the test solution, and can accurately test the content of sulfate ions in hardened concrete. The sulfate ion content of concrete at different depths was tested, and it was found that the two sides of sulfate erosion caused by freeze-thaw cycles were mainly reflected in about 100 freeze-thaw cycles. The limit number of freeze-thaw cycles N0 and the limit diffusion depth X0 are proposed, and the diffusion equation of manufactured sand concrete under the action of sulfate freeze-thaw cycles is derived. The proposed diffusion parameter v is unique to the concrete, which can well judge the sulfate freeze-thaw resistance of the concrete. When v is closer to 0, it shows that the resistance of concrete to sulfate freeze-thaw erosion is better. For the northwest environment of China, the manufactured sand concrete should ensure v < 6; the environment in Northwest China has a very complex multi-factor erosion environment. It is worth noting that this study is only applicable to laboratory conditions. To improve the accuracy and reference value of experimental research, future research needs to add more comprehensive environmental impact factors and collect actual data in the northwest environment of China for verification.

Environmental sustainability and life cycle assessment of pilot scale application of coal combustion residue as structural fill in mechanically stabilized earth walls

In this study, three types of coal combustion residue (CCR) have been used, and the life cycle impact of CCR as structural fill behind mechanically stabilized earth (MSE) walls of three different heights has been conducted. The analysis has been done using OpenLCA software. Results have been compared with MSE walls using natural sand as a structural fill. It is observed that the environmental impacts of using CCR reduce by more than 50 % compared to those of using natural sand. Amongst CCR, the maximum impact is shown by fly ash and the least by bottom ash. Relative to natural sand, the impacts of using CCR decrease with an increase in wall height. The cost analysis of the walls indicates that if structural fills are transported from the same distance, the cost of construction with natural sand is 18–46 % higher than that by CCR as fill. Results reveal that utilizing CCR as structural fill in MSE walls proves to be a more economic and eco-conscious choice compared to the conventional natural soil. These findings could hold considerable implications for the construction sector and its efforts to minimize ecological footprint.

Concrete containing recycled concrete coarse aggregate and crushed glass sand: Mitigating the effect of alkali–silica reaction

AbstractThe utilization of recycled concrete and glass aggregates in concrete production has emerged as a highly promising method to significantly increase the recycling rate of waste materials. However, the interaction between alkaline environment and silica present in concrete detrimentally impacts mechanical properties and durability of the concrete due to the significant silica content of the aggregates. This study aims to develop a high‐performance and sustainable concrete to resist alkali–silica reaction (ASR). The study focuses on the use of a blend of ground granulated blast furnace slag (GGBS) and fly ash (FA) as binder materials to mitigate negative effects of the ASR on the mechanical properties and and durability of concrete made with crushed glass sand and coarse recycled concrete aggregate (RCA). Various tests, including ASR expansion, flow, slump, density, compression, three‐point bending, water absorption, and chloride attack, were conducted. Furthermore, microanalysis using scanning electron microscopy and energy‐dispersive x‐ray spectroscopy was performed. Based on the results, it is found that the GGBS is less effective than the FA in reducing the ASR expansion of the concrete, with only 3%, 9%, and 12% decreased expansion as a result of the addition of 20%, 40%, and 70% GGBS to the concrete containing 30% FA, respectively. It is also shown that combining 20% GGBS with 30% FA in the RCA concrete containing glass sand develops similar compressive and flexural strengths and water absorption compared to that containing natural sand. This can be related to the pozzolanic reaction of the FA and GGBS, which helps to retain the alkalis for reducing the crack development and propagation in the concrete. However, further GGBS content leads to a decrease in the strengths and an increase in the water absorption of the concrete. The results of this study point to the significant potential of combining FA and GGBS at an optimum ratio to mitigate the ASR effect on RCA concretes containing crushed glass sand. This approach helps in minimizing the emission of greenhouse gases and other pollutants generated during cement production, thereby mitigating environmental pollution. Additionally, it helps the preservation of natural resources by reducing the depletion of natural sand and coarse aggregate.

Effects of Waste Plastic and Glass Aggregates on the Strength Properties of Ambient-Cured One-Part Metakaolin-Based Geopolymer Concrete

The production of Portland cement (PC) is associated with carbon emissions. One-part geopolymer “just add water” is a user- and environmentally-friendly binder that can potentially substitute PC. However, there is limited research on the setting time, fresh, and strength properties of one-part metakaolin (MK)-based geopolymer concrete (OMGPC) incorporating recycled aggregates. Hence, the study explored the fresh, mechanical (compressive, flexural, splitting tensile, and E-modulus) and microstructural properties of ambient cured (7-, 28-, and 90-day) OMGPC containing recycled waste plastics (RESIN8) and recycled fine waste glass aggregate (FWG) at 5% and 10% by volume of the sand. The study result shows that 2% trisodium phosphate by wt. of the binder retard the initial and final setting times of OMGPC. At the same time, the incorporation of RESIN8 and FWG aggregates improved the workability of geopolymer concrete. The lightweight properties of RESIN8 aggregate reduce the hardened density of OMGPC, while the FWG specimens show a similar density to the control. The compressive strength of RESIN8 and FWG OMGPC range from 19.8 to 24.6 MPa and 26.9 to 30 MPa, respectively, compared to the control (26 to 28.9 MPa) at all curing ages. The flexural and splitting tensile strength of the OMGPC range from 2.2 to 4.5 MPa and 1.7 to 2.8 MPa, respectively. OMGPC is a viable alternative to Portland cement, and FWG can substitute sand in structural concrete by up to 10% and RESIN8 aggregate at 5% by volume of the natural sand.

Effect of sand–precursor ratio on mechanical properties and durability of geopolymer mortar with manufactured sand

Abstract The geopolymer mortar (GPM) prepared from industrial by-products and alkali activation solution (AAS) is one of the hot spots of current building materials. As a feasible alternative to natural river sand, manufactured sand (MS) alleviates the global ecological pressure. In this study, MS was used for fine aggregate. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solution were used as AAS. Metakaolin (MK) and fly ash (FA) were used as the precursor to prepare MK-FA-based GPM with MS (MS-GPM), which was of great significance for saving non-renewable resources, mitigating the greenhouse effect, and recycling waste. Numerous studies were conducted to explore the effect of sand–precursor ratio (r sp) on mechanical and durability characteristics of MS-GPM. Relationships between compressive strength and tensile or flexural strength were established by linear fitting equation. Finally, analysis of variance (ANOVA) was used to systematically calculate the effect of r sp on performance. The results indicated that the mechanical strength and impermeability of MS-GPM decreased and crack resistance increased with r sp from 1 to 5. The strength of MS-GPM was the best when r sp was 1. With the increase of r sp, the proportion of MS in MS-GPM increases, and the relative cementitious material decreases, which has an adverse impact on mechanical properties and impermeability. Linear fitting revealed that the compressive strength of MS-GPM was closely related to tensile strength and flexural strength. ANOVA results indicated that r sp in the range of 1–5 had great effects on the performance of MS-GPM. The aim of this article is to further promote the possibility of applying MS-GPM in practical engineering by designing reasonable r sp.

Characteristics of Fibre-Reinforced Cement-Sand Blocks with Quarry Dust as Replacement for Sand

The present investigation delved into the mechanical performance of fibre-reinforced cement-sand blocks with quarry dust as a replacement for sand. The introduction of fibres and quarry dust in the matrix is an attempt to achieve higher performance with available cement content and reduce the utilization of natural sand to improve the sustainability of the product. The experimental programme attempted to study the influence of quarry dust on the density, compressive strength, water absorption, sorptivity, and efflorescence characteristics of the blocks. The parameters considered include quarry dust (QD) content (replacement of sand from 0% to 100% in increments of 20%), a constant fibre content of 0.5%, and a constant water-cement ratio of 0.5. An attempt was also made to compare the strength performance of the blocks with various code requirements as well as results from similar previous investigations. The replacement of sand with QD resulted in a reduction in the density of the blocks from 2365 kg/m3 to 2008 kg/m3. The results of the investigation revealed that 60% quarry dust replacement of natural sand developed the maximum strength of the blocks. After 28 days of curing, blocks with up to 60% QD replacement were able to produce strength more than 16 MPa. The water absorption increased only marginally from 5.52% to 5.83% for 60% QD replacement. Moreover, the blocks were able to meet the requirements of all the different types of blocks as stipulated by Bureau of Indian Standards including stabilized soil blocks, concrete solid blocks, concrete hollow blocks, lime-based blocks, and lime-flyash blocks of class up to 17.5.

Multicriteria Analysis of Cement Mortar with Recycled Sand

Sustainable development requires a holistic perspective that integrates the different aspects of production and consumption and promotes the transition to a circular economy. This approach aims to balance the needs of the present and future generations, as well as the social, environmental, and economic dimensions of development. By producing products that are durable, recyclable, and reusable, and by minimizing the use of energy and materials, the environmental impact of production can be reduced while also generating economic benefits and enhancing social well-being. The article addresses the multicriteria sustainability of producing mortar modified with sand from recycled concrete rubble. The research explored the possibility of replacing natural sand with recycled sand in proportions from 10% to 100%. The consistency of mixtures, flexural and compressive strengths after 2, 28, and 90 days, as well as the carbon footprint and cost of the aggregate used were analyzed. The waste management index and sustainable use of natural resources were also considered. The research and analysis showed that recycled sand could be successfully used as an alternative for natural aggregate, as there are clear environmental and economic advantages, and the basic technical characteristics do not differ significantly statistically from the unmodified composite.

Feasibility of using pretreated sodium silicate-bonded waste foundry sand as fine aggregates for construction mortar

Insufficient utilization of sodium silicate-bound waste foundry sand (SS-WFS) in construction is due to the presence of harmful residual sodium silicate film on the sand surface, which are detrimental to cement hydration. Based on previous research, this study proposes a pretreatment method using another industrial waste, calcium carbide slag (CCS), to effectively remove pollutants from sodium silicate-bounded waste foundry sand (SS-WFS). The feasibility of pretreated SS-WFS as an alternative to natural sand and optimal washing duration were investigated. The results demonstrate that pretreated SS-WFS exhibits promising potential as a substitute for 100% natural sand as a fine aggregate within the construction industry, while demonstrating comparable mechanical properties to those of natural sand mortar. The residual sodium silicate film on the surface of SS-WFS undergo secondary hydration, leading to the formation of hydration products with a low calcium-to-silicon ratio in interfacial transition zone. This enhances the mechanical properties of the mortar and improves its deformation characteristics. The optimal washing duration is determined to be 5 min with 1% CCS, and compared to RS-0, the mortar strength has increased by 70%. Extended washing duration may cause the depletion of beneficial components, such as active Si2O, from the sand surface.

Recycling of municipal solid waste incineration bottom ash (MSWIBA) particles into natural fine sands for sustainable engineering cementitious composites

The manufacture of engineered cementitious composites (ECCs) consumes large amounts of natural fine aggregate. In this study, replacement of the natural fine aggregates in ECCs with municipal solid waste incineration bottom ash (MSWIBA) was found to reduce the consumption of natural river sand and the negative environmental impact of MSWIBA disposal. Previously, scholars have shown the potential of using MSWIBA particles as fine aggregates in concrete, but few scholars have evaluated ECCs with high percentages of MSWIBA powder in place of the natural fine aggregates. This study was conducted to design green ECCs by incorporating MSWIBA (BA–ECCs) to completely replace the natural silica sand with various fibers (PVA, PP and PE) and different fiber volume blends (0%, 0.5%, 1%, 1.5% and 2%) and to evaluate the BA–ECCs based on the fluidities, mechanical properties, microscopic morphologies, pore size distributions and heavy metal leaching capacities. The results showed that the addition of MSWIBA increased the porosities of the BA–ECCs. Compared with those of the control group, the maximum flexural strength of the BA–ECCs with 1.5% fiber doping were approximately 27.75% higher. There were relationships between the compressive strength and flexural strength and between the fiber volume content and strength. Moreover, microstructural observations revealed that the MSWIBA powder interacted strongly with both the matrix and the fibers, and the performance of the MSWIBA powder in the matrix was similar to that of a lightweight aggregate during internal curing. Additionally, fiber agglomeration (winding) at a 2% fiber content reduced the compressive and flexural strengths. The BA-ECCs showed lower heavy metal leaching contents than the MSWIBA, and the concentrations of various heavy metals were below the Chinese standards. Overall, this study could support research on the use of MSWIBA particles to prepare sustainable ECCs and recycle MSWIBA particles.

An AHP based sustainability assessment of cement mortar with synergistic utilization of granite cutting waste

The valorization of various waste in construction sector is viewed as a sustainable measure. Protecting natural resources and minimizing waste lays the foundation for sustainable development. The study is aimed to identify the optimum utilization of granite cutting waste (GCW) in sustainable rendering mortar development. The comprehensive study is performed for cement mortar mix of 1:3 (volumetric) by replacing natural sand with 10 % range up to 50 % by GCW powder. The mortar is evaluated for flowability, Fresh density, Compressive resistance, Flexural resistance, Adhesiveness with substrate, Drying shrinkage, Water absorption capacity, Percentage voids, Hardened bulk density, Ultrasonic Pulse Velocity, and Dynamic Modulus of Elasticity parameters. It is observed that, for 30 % replacement, the compressive strength increased by 75 % compared to control mortar for the 28 days curing period. The maximum flexural strength 2.99 N/mm2 is achieved for 30 %, and the highest adhesive strength, 0.89 N/mm2, is noted for 20 % replacement. Also, the microstructural studies are performed to assess the effect on the hydration of the cement. The sustainability evaluation, performed by life cycle assessment methodology, revealed that higher substitution of GCW helps in lowering the environmental impacts for cradle to gate life cycle phase of the mortar. Abiotic depletion potential Fossil Fuels and Ozone depletion potential has contributed to 19.56 and 18.82 % lower impacts for 20 % substitution by granite. The mortar mixes with varied substitutes of granite waste were also evaluated and ranked using the Analytical Hierarchy Process (AHP). In comparison to conventional rendering mortar, the AHP findings show that the mortar mix with 30 % granite waste integration scores highest above all other replacements, indicating its potential as an efficient and environmentally friendly choice. The GP50 mortar mix rated highest on Eco-efficiency index result. However, at optimum substitution of 30 %, the eco-efficiency index lies above average line.

A COMPARISON OF THE USE OF RECYCLED CONCRETE AS A SUBSTITUTE FOR COARSE AGGREGATE AND THE EFFECT OF ADDING SILICAFUME IN TERMS OF THE COMPRESSIVE STRENGTH OF CONCRETE

One of the most widely used building materials on the planet is concrete. However, the production of concrete requires large amounts of natural resources such as sand and gravel. It is becoming increasingly difficult and costly to obtain these resources. Recycled concrete aggregate may be substituted for natural sand and gravel. Recycled concrete is the material used for RCA which would normally be discarded. It may help to reduce construction's impact on the environment by using RCA in concrete form. This could contribute to protecting natural resources, reducing greenhouse gas emissions from buildings, and, generating jobs in the recycling sector. The coarse aggregate was made up of 30% recycled concrete during the study.

Post-fire properties of lightweight 3D printed concrete containing expanded perlite

There has been an increase in construction with three-dimensional (3D) printing technology but 3D printed (3DP) structures also require weight reduction similar to conventional reinforced concrete structures. In addition, the behaviour of this type of structure against fire needs to be investigated. The number of printed layers and the time gap between layers for the 3DP specimens were among the variables examined. The test results demonstrate that as the replacement percentage of natural sand (NS) with expanded perlite (EP) increased, at 25% volume of replacement, the interlayer bond strength increased on average by 18.6%, while at the highest replacement level, of 75%, the strength decreased on average by 5.8%. Additionally, by incorporating EP, the compressive and flexural strengths of 3DP specimens declined on average from 9% to 29.7%, and from 39.3% to 49.3%, respectively. As the replacement level of NS increased, residual compressive and flexural strengths increased after exposure to 800°C. Furthermore, it was demonstrated that exposure to high temperature had the least effect on interlayer bond strength, whereas it significantly reduced the compressive and flexural strength. The results show that increasing the time gap between layers reduced interlayer bond strength and flexural strength while negligibly affecting compressive strength.

Shifting the Sands – Early Islamic Modification of the Caesarea Sandy Lowlands into Plot-and-Berm Water-Harvesting Agroecosystem

ABSTRACT During the Early Islamic period, several emerging agricultural innovations enabled the cultivation of summer crops in unproductive Mediterranean lands. This necessitated the development of water harvesting methods. This study delves into the creation of the Plot-and-Berm (P&B) agroecosystem along the sandy coast of Caesarea, Israel. From the early tenth century to the mid-twelfth century, coeval to the later part of the Early Islamic period and the beginning of the Crusader period, a 1.5 km2 P&B agroecosystem was constructed and maintained. Remarkably, this system still dominates the landscape. The agroecosystem’s expansion was controlled by regional hydrological, geological, and climatic factors. Anthropogenic sedimentary units include the anthrosol found within the plots and anthrosediment within the berms with densely added refuse. Sedimentological and mineralogical analysis of the anthrosol and anthrosediment unveils the additives of calcitic fine-grains, likely originating from nearby kilns. The arrangement of these fine grains amidst quartz particles fills pore spaces, reducing the hydraulic conductivity of the natural sand. Similar to other sandy agricultural systems, morphological and sedimentological adaptations were employed to sustain a pattern of annual crop yields, by capturing rainfall water for crop cultivation during the rainy season, while high groundwater levels facilitated summer cultivation.

Effect of replacing natural sand by quarry waste sand in recycled aggregate concrete

This paper investigates the effect of quarry waste sand (QWS) on the physical and mechanical properties of recycled aggregates concrete (RAC). Two sets of concretes were made one with natural sand (NS) and another with QWS sand. Five mixes with replacement ratios of 20%, 40%, 60%, 80% and 100% of ordinary coarse aggregates (OCA) by recycled concrete aggregates (RCA) were produced for each set. Tests were performed to determine slump, compressive strength, flexural strength, water absorption by immersion and shrinkage. The results showed that the mixes produced with QWS sand exhibited slightly better fresh and hardened properties. The combination of QWS sand and RCA aggregates reduces the degradation often recorded and makes RAC concrete to have the same level of performance as concrete with ordinary aggregates. Some relationships were deduced to express each performance of QWS sand-based concrete with that of NS sand-based concrete. This makes the use of this sand very practical and its modifications easily quantifiable.

Parameters adjustments for facile synthesis of high magnetization iron oxide nanoparticles from natural sand

This study explores the synthesis of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) by leveraging natural iron sand and steel wool as primary raw materials within the co-precipitation method, which reduces the cost of production compared to the commercial counterparts. The research systematically investigated the influence of the diethylamine percentage, annealing time and annealing temperature on the SPIONs’ synthesis from natural iron sand by the co-precipitation method. Fe3O4 with varying crystallite sizes, ranging from 11.5 to 14.7 nm, were confirmed. SEM highlighted the nanoparticle agglomeration, a concern addressable through surface modification techniques, as further emphasized by TEM, which confirmed the nano-scale dimensions. Magnetic saturation values were confirmed by VSM, ranging from 37 to 51 emu/g. These values established the superparamagnetic behavior, rendering the nanoparticles suitable for versatile applications. The study identifies a potential threshold effect of the diethylamine concentration on the magnetic saturation and suggests an optimum annealing temperature for energy efficiency. This research contributes valuable insights into harnessing natural iron sand for SPION synthesis, advancing cost-effective and sustainable approaches in nanomaterial development, while emphasizing the importance of parameter customization for producing high-quality SPIONs.

Optimization of eco-friendly concrete with recycled coarse aggregates and rubber particles as sustainable industrial byproducts for construction practices

In this technology era, sustainable construction practices have become quite imperative. The exploration of alternative materials to reduce the environmental footprint is of paramount importance. This research paper delves into an exhaustive investigation concerning the utilization of recycled coarse aggregates (RCA) and rubber particles (RP) in concrete. It contributes to the growing body of knowledge aimed at fostering sustainable development in the construction industry by reducing waste, promoting recycling, and mitigating the environmental footprint of building materials. The objective of the study is to evaluate the potential benefits and limitations associated with incorporating these materials, thereby providing a sustainable alternative to conventional concrete. In this research, construction and demolition waste were recycled and used as RCA as a fractional switch of natural coarse aggregate (NCA) from 0% to 100%, with an increment of 20% replacement of NCA in concrete. The RP received from discarded tires generated as automobile industry waste were used as a volumetric fractional substitution of sand in concrete from 0% to 20%, with a 5% increment. No pre-treatment for RCA and RP was carried out before their utilization in concrete. A total of 26 mixes, including control concrete without NCA and RP, with a design strength of 40 MPa, were prepared and tested. Concrete mixes were examined for workability, density, mechanical, and durability properties. It was found that the concrete with 60% RCA and 10% RP showed satisfactory results in evaluation with the strength parameters of control concrete, as the compressive strength obtained for this concrete mix is 40.18 MPa, similar to the control mix. The optimization for RCA and RP was conducted using Response Surface Methodology (RSM). The major concern observed was a rise in water absorption with an increase in the percentage replacement of NCA and natural sand by RCA and RP. Findings from the investigation illustrate a promising prospect for the use of RCA and RP in concrete applications, displaying competent mechanical properties and enhanced durability under certain conditions, offering a viable option for environmentally friendly construction practices. However, the research also sheds light on some constraints and challenges, such as the variability in the quality of RCA and the necessity for meticulous quality control to ensure the reliability and consistency of the end product. It is discerned that further refinement in processing techniques and quality assurance measures is pivotal for mainstream adoption of RCA and RP in concrete construction.

Wall-resolved large eddy simulation of mixed-size sand-laden flow

Most of the existing numerical studies on wind-blown sand flow simplify sands into single-size particles, whereas natural wind-blown sand flow is a two-phase flow with mixed-size particles, thus, the simulation of mixed-size sand-laden flow is necessary. In the present work, wall-resolved large eddy simulations of mixed-size sand-laden flows are realized. Each sand in the wind field is tracked using the Lagrangian point-particle model. The transport characteristics of sand particles in mixed-size sand-laden flow are investigated under the premise of considering bed erosion. Considering the significant influence of sand-bed collision on simulation, the splash function is modified in the present simulation according to the previous experimental results. It reveals that in mixed-size sand-laden flow, the fraction of rebound sand particles in all the saltation particles is approximately 0.6, which is twice times of the ejected sand particles, and the modification of the sand rebound angle greatly affects the simulation results of mixed-size sand-laden flow. Meanwhile, the mean size of the saltation sand particles decreases with height and is 20% lower at the top of the saltation layer than that near the sand bed in the present simulation. Further analysis by grouping of sands with their size shows that the sand transport intensity of small sands decreased more rapidly with increasing height. The volume fraction and sand transport intensity of small sand particles exceed those of medium and large sand particles at heights y/δ = 0.05 and y/δ = 0.1.

Effect of Various Methods of Curing on Concrete Using Crusher Dust as Replacement to Natural Sand

AbstractThe present paper highlight upon research work is that curing is one of most important aspect of construction. The life of concrete and its serviceability depends heavily on curing. The method of curing applied on concrete will affect its final strength and durability. Owing to this fact this paper contains the research done on concrete under various curing methods. The standard method of curing concrete is done by water and results wastage of a lot of water. With the increase in the deficiency of availability of water, curing becomes a problem. Hence this research aims at providing better methods of curing which will not only improve the strength and durability of concrete but will also save water. The various methods that have been researched upon are plastic covered curing, addition of sodium silicate to curing water, and addition of curing compounds to curing water. The tests are carried on concrete with desirable strengths of M15 and M20. In this research the fine aggregate used in making of M15 and M20 concrete consists of a mixture of sand and crusher dust. Two mixes of ratio 50:50 and 60:40, sand to crusher dust have been taken and the effects of curing on these mixes are considered. Plastic curing is done by covering the concrete with plastic soon after demolding. Hence minimum water is required. The curing done by sodium silicate is done by adding 2% by weight of sodium silicate to curing water. Concrete is submerged in water containing sodium silicate. Once the concrete is cured, this water mix can be reused to cure freshly cast concrete, thereby saving more water. Curing by curing compounds is done in a similar way as that of curing with sodium silicate, only that instead of sodium silicate, curing compounds are used. The effect of these three methods on concrete is studied and discussions are made.

Evaluating Properties of Green Concrete Produced Using Waste Marble Powder, Quarry Dust, and Paper Pulp

AbstractIndustrial waste locks are used as raw materials to reduce harmful effects on the environment and improve environmental performance. Marble clay powder can be used as a filling aid and can fill voids in concrete structures. This article will show you how to use a maximum natural sand alternative in concrete with marble powder and quarry dust. The challenge of the 21st century is to change to a new form that can support the natural system. This necessitates a radical rethinking of how to give the community infrastructure and housing. Making a concerted effort to develop novel, innovative, and alternative construction materials may be necessary. Jungles of concrete around cause's impact on the Environment and it would result in climate change. Mankind must avoid the use of things that are detrimental to the environment. So in this paper, it is decided to address the issue by adopting the use of the green concrete concept which is environmentally friendly. Green concrete is concrete made up using industrial wastes such as marble powder, quarry dust, wood ash, paper pulp, etc. Green concrete, which is capable of sustainable development, helps to reduce the consumption of natural resources, energy use, and environmental pollution. Green concrete is more cost‐effective than ordinary concrete and reduces the cost of resultant concrete by 14%–20%. It is also observed that the alkali‐aggregate reaction and sulfate attack resistance of concrete are both significantly improved. Green concrete is a useful tool for lowering environmental pollution and enhancing concrete's resistance to harsh conditions. All stages of infrastructure construction and rehabilitation will follow this trend of using new cement and techniques. Green concrete's adaptability and its performance derivatives will meet a variety of future needs.