River Sand Research Articles

Design, modelling and optimisation of ultra high-performance fibre reinforced concrete incorporating waste materials

The adoption of ultra-high-performance fibre-reinforced concrete (UHPFRC) in modern-day construction has gradually increased because of its high compressive and flexural strength at the early production ages. The UHPFRC's high initial cost discourages its production and widespread use. This cost can be reduced by incorporating waste materials in UHPFRC production. This study aims to design, model, and optimise a three-day heat-cured UHPFRC incorporating waste materials. To produce a sustainable UHPFRC mixture, this study combines rice husk ash (RHA) and recycled tire steel fibre (RTSF) as the primary waste components, with Portland limestone cement, river sand, superplasticizer, and water. The concrete is heat-cured in a hot water bath at 90 °C for 3 days, resulting in rapid strength development. A D-optimal mixture design technique was used to optimise the mix proportions, and mathematical models were developed to predict the compressive and flexural strengths. The non-significant lack-of-fit results and the high values of coefficient of determination (R2) revealed the accuracy of the models in predicting the compressive and flexural strengths of the UHPFRC. The low values of standard deviation (SD) and coefficient of variation (CV) confirmed the consistency and reliability of the prediction models. A numerical optimisation revealed that it is possible to design a UHPFRC mixture with a lower cement content of 38.29% of the UHPFRC mix, resulting in a compressive strength of 117.62 MPa and a flexural strength of 36.32 MPa. The study reveals that integrating RHA and RTSF into UHPFRC can yield high-performance properties, offering innovative solutions for resource scarcity and environmental sustainability in the construction sector.

Development of sustainable, high strength slag based alkali activated pavement quality concrete using agro-industrial wastes: properties and life cycle analysis

ABSTRACT Alkali-activated binder-based composites offer a sustainable alternative to cement-based systems, giving a conservational approach. This research incorporated rice-husk ash (RHA) and waste foundry sand (WFS) into ground-granulated-blast-furnace slag (GGBS)-based alkali-activated high-end pavement-quality concretes, optimising with air-curing for expressways, freeways and runway applications. This study promotes sustainable construction by efficiently utilising agro-industrial wastes (i.e., RHA, GGBS and WFS) promoting a global initiative to decrease environmental impact and to adopt eco-friendly pavement construction methods. This study systematically substitutes the primary binder-GGBS with RHA at 5% intervals. The binder was alkali-activated using measured amounts of liquid sodium silicate and sodium hydroxide flakes prepared at an activator modulus (Ms) of 1.25 by maintaining the sodium oxide dosage of 4.0% with respect to the total binder. In particular, 15% RHA (with 85% GGBS) and 20% WFS (with 80% river sand) satisfy mechanical design standards for workability and strength. A comprehensive life cycle analysis using extensive literature support assesses the environmental impact and sustainability of developed pavement quality composites, showing over 70% less energy use than Portland cement-based pavement mixes. Therefore, employing RHA and WFS in air-cured alkali-activated composite manufacture shows that agro-industrial waste components may be used to make sustainable, cost-effective pavement construction. This study effectively advocates for a shift towards environmentally responsible pavement construction, contributing to a greener, more sustainable future in concrete pavement engineering.

Effect of Polypropylene Fibers on the Behavior of Dune Sand Concrete Subjected to Elevated Temperatures

In the field of civil engineering, concrete is one of the most used materials. Above a particular temperature, concrete can exhibit thermal instability during fire events. Improving the safety of buildings and structures is an important issue of this study. This paper investigates the effects of adding polypropylene fibers to dune sand concrete at high temperatures. Prismatic specimens (4 x 4 x 16 cm3) are produced, and stored until the concrete is hardened. The samples are then subjected to a heating-cooling cycle, starting from room temperature and increasing by 0.1 °C/min until reaching 600 °C. The length and the rate of polypropylene fibers are examined to determine their impact on compressive strength, porosity, and weight loss at temperatures of 80, 150, 300, 450, and 600 °C. Also, the partial replacement of dune sand (DS) with river sand (RS) is investigated. The results show that, for temperatures below 450 °C, the strengths of dune sand concretes varied from 29 to 39% compared to those obtained with concretes subjected to an ambient temperature (20 °C). However, it should be noted that residual compressive strength values decrease at most temperatures with the addition of polypropylene fibers. Furthermore, sand concrete with 50% DS and 50% RS shows an increase in compressive strength of 43.77% compared to that obtained by 100% DS concrete.

Alternative Fine Aggregates to Natural River Sand for Manufactured Concrete Ensuring Circular Economy

To address SDG12 (ensure sustainable consumption and production patterns), and to provide technical evidence for alternative concrete constituents to traditional natural river sand, stone fine aggregate (SFA), brick fine aggregate (BFA), ladle-refined furnace slag aggregate (LFS), recycled brick fine aggregate (RBFA), and washed waste fine aggregate (WWF), ready-mix concrete plants were investigated. Concrete and mortar specimens were made with different variables, such as replacement volume of natural sand with different alternative fine aggregates, water-to-cement ratio (W/C), and sand-to-aggregate volume ratio (s/a). The concrete and mortar specimens were tested for workability, compressive strength, tensile strength, and Young’s modulus (for concrete) at 7, 28, and 90 days. The experimental results show that the compressive strength of concrete increases when natural sand is replaced with BFA, SFA, and LFS. The optimum replacement amounts are 30%, 30%, and 20% for BFA, SFA, and LFS, respectively. For RBFA, the compressive strength of concrete is increased even at 100% replacement of natural sand by RBFA. For WWF, the compressive strength of concrete increases up to a replacement of 20%. Utilizing these alternative fine aggregates can be utilized to ensure a circular economy in construction industries and reduce the consumption of around 30% of natural river sand.

Valorization of phosphate mine waste rock as alternative aggregates for high-performance concrete

Natural aggregate quarrying significantly impacts the environment while phosphate mine waste rock (PMWR) offers alternative aggregates for use in high-added value construction materials. This study was the first to investigate the application of three aggregate types from PMWR as a complete substitute to natural aggregate to produce high-performance concrete (HPC). For this aim, three coarse aggregate (CA) types: Flint (F), Phosflint (PF), and Dolomite (D) from PMWR in Morocco were selected and compared with a natural Reference CA (R). Two mixtures were tested: HPC-0.40 and HPC-0.36 with a w/c ratio equal to 0.40 and 0.36. D-HPC and PF-HPC achieved a slump exceeding 20 cm and a 28-d compressive strength (CS) equal to 55 MPa ± 5 MPa on average, similar to the R-HPC, while F-HPC did not meet the requirement for HPC (i.e. a 28-d CS superior to 55 MPa). Scanning electron microscope observations showed that D-HPC exhibited a very dense and indistinguishable interfacial transition zone (ITZ), while F-HPC showed a debonding of F-CA and a larger ITZ size which explain its lower CS. Life ycle assessment revealed a major positive environmental impact on ecosystem quality that reduced land occupation and land transformation by up to 32 %. A secondary evaluation of the valorization of PMWR as alternative fine aggregate (FA) in high-strength mortar (HSM) was investigated and showed that the 28-d CS is equal to 93 MPa for PF-HSM and equal to 81 MPa for D-HSM, superior to RS-HSM which is equal to 61 MPa. Dolomite and Phosflint FA offered a better alternative to natural River sand to overcome the ceiling effect. These findings encourage the construction sector to adopt a sustainable consumption of aggregates by using PMWR as alternative CAs and FAs to produce high-strength construction materials.

Application of 3D Geological Modeling Technology for Single Sand Body in Block S

Abstract The P oil layer is generally in a medium to high water cut period, with scattered macroscopic residual oil distribution. The reserves are mainly distributed in the microfacies of river sand bodies, and the main layer is severely flooded with water, resulting in ineffective circulation in some areas. Therefore, it is necessary to tackle the modeling technology within the layer and describe the remaining oil within the layer to meet the needs of tapping the potential of remaining oil during the high water cut period. This article takes the establishment of a three-dimensional geological model of a single sand body within the S block layer as an example. Based on the establishment of a fine structural model, the “plane and vertical dual control” modeling method is used. The implementation method is: controlling the range of sedimentary facies maps → using the top surface of the sand body as the top depth of the river channel → controlling the vertical shape of the river channel through the facies controlled sandstone contour map, thereby achieving the vertical shape of the river channel through the facies controlled sandstone contour map, and establishing a three-dimensional sedimentary facies model of a single sand body. Optimize the method for characterizing interlayers, achieve modeling of single sand body interlayers, and perform random simulation interpolation in phases to obtain attribute models. The use of a single sand body model within a layer can visually display the three-dimensional channel morphology and classify the identified connected bodies within the study area. The upscaling method of sedimentary facies models with irregular boundaries greatly reduces the number of model grids and provides a relatively refined geological model for numerical simulation.

Characteristics of self-compacting green concrete

Locally, conventional concrete is still created utilizing river sand and crushed stone as filer materials. The massive quarry dust by-product remain untapped in the production of concrete. The coal-fired power station produce significant quantities of Type F fly ash. Self-compacting concrete (SCC) provides many advantages for creating high-quality concrete. Consequently, the main objective of this research is to create a mix design for high-strength SCC utilizing a binary blends, hybrid fibers and fine aggregates that meet both hardened and fresh concrete characteristics. The study is conducted in amendment of w/b ratio, superplasticizer, proportion of fine aggregate to coarse aggregate, optimumal cement replacing by fly ash, dosage of low macro fibre and micro fibre. Mix-50c-X is the best mix design that was produced. The mix quantity for 1m3 concrete was 315 kg Class F fly ash, 315 kg OPC, 630 kg quarry dust, 508 kg river sand, 400 kg coarse aggregate, 0.7% superplasticizer,0.32% w/b, 0.10% macro fiber, and 0.01% micro fiber. This SCC mixture showed fresh characteristics as well as compressive strengths of more than 22 MPa and 62 MPa after 1 day and 28 days, respectively. The results of high-strength SCC demonstrated the enormous potential for the local construction, especially precast product.

Quantitative analysis of the fluvial geomorphology and erosion on Hainan island: implications for the source-to-sink system in the NW South China Sea

The sediment delivery from Hainan island into the NW South China Sea during the Quaternary is less well-defined. An investigation into the uplift, exhumation and fluvial geomorphology of the Hainan island is crucial for improving our understanding on the source-to-sink system in this region. In this study, we employed the digital elevation analysis, the stream power incision model and the cosmogenic nuclide isotope analysis to unravel how and why the Hainan island provide sediment to the NW South China Sea. The results show that the average HI values of the main catchments on the Hainan island are below 0.35, which indicates that the rivers on the Hainan island tend to be stable. After mapping the channel steepness index of the Hainan island, a high channel steepness index is constrained in the central and western Hainan island. The χ analysis shows minor variations in χ values across the Hainan island, except of the watershed between the Wanquanhe and Nandujiang rivers, as well as that between the Changhuajiang and Nandujiang rivers, which indicates the potential migration of the river watersheds here. In addition, we carried out the cosmogenic nuclide 10Be analysis on the river sand from the Hainan island. The spatial distribution of 10Be concentrations is identified to be high in the west and low in the east. The catchment-averaged erosion rates are quantified to be 35 m/Myr, 42.5 m/Myr and 69.9 m/Myr for the Changhuajiang, Wanquanhe and Lingshuihe catchments, respectively. We also estimated the sediment deliveries from the Changhuajiang, Wanquanhe and Lingshuihe catchments to the Qiongdongnan and Yinggehai Basins to be 0.46 Mt/yr, 0.45 Mt/yr and 0.21 Mt/yr, respectively. We compared our results of the fluvial geomorphology analysis and erosion rate estimates of the Hainan island with those of the Taiwan island. We concluded that the difference of the erosion pattern and river evolution of the Hainan and Taiwan islands may be associated with the variation of the tectonics. Our investigation on the evolution of the Hainan island will improve our understanding on the source-to-sink systems in the NW South China Sea.

Copper Mining Solid Waste as Replacement Aggregate of River Sand in Cement Mortar to Investigate the Effect on Fresh, Durability and Microstructural Properties: A Walkthrough to Sustainability

Copper Mining Solid Waste as Replacement Aggregate of River Sand in Cement Mortar to Investigate the Effect on Fresh, Durability and Microstructural Properties: A Walkthrough to Sustainability

A Study of the Influence of Thermoactivated Natural Zeolite on the Hydration of White Cement Mortars.

One trend in the development of building materials is the partial or complete replacement of traditional materials that have a high carbon footprint with eco-friendly ecological raw materials and ingredients. In the present work, the influence of replacing cement with 10 wt% thermally activated natural zeolite on the structural and physical-mechanical characteristics of cured mortars based on white Portland cement and river sand was investigated. The phase compositions were determined by wavelength dispersive X-ray fluorescence (WD-XRF) analysis, X-ray powder diffraction (PXRD), diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS), and scanning electron microscopy (SEM), as well as thermogravimetric analysis simultaneously with differential scanning calorimetry (TG/DTG-DSC). The results show that the incorporation of zeolite increases the amount of pores accessible with mercury intrusion porosimetry by about 40%, but the measured strengths are also higher by over 13%. When these samples were aged in an aqueous environment from day 28 to day 120, the amount of pores decreased by about 10% and the compressive strength increased by nearly 15%, respectively. The microstructural analysis carried out proves that these results are due to hydration with a low content of crystal water and the realization of pozzolanic reactions that last over time. Replacing some of the white cement with thermally activated natural zeolite results in the formation of a greater variety of crystals, including new crystalline CSH and CSAH phases that allow better intergrowth and interlocking. The results of the investigations allow us to present a plausible reaction mechanism of pozzolanic reactions and of the formation of new crystal hydrate phases. This gives grounds to claim that the replacement of part of the cement with zeolite improves the corrosion resistance of the investigated building solutions against aggressive weathering.

Influence of fines and gravel particles on strength-dilatancy of river sand: Effect of depositional conditions

Understanding the effects of low plastic fines and gravel contents on the mechanical behavior of sandy soils in terms of the strength-dilatancy relationship is crucial for various geotechnical applications. To gain deeper insights, an extensive series of direct shear tests were performed on two distinct types of mixtures: sand-fines mixtures and sand-gravel mixtures. The study systematically varied Fc/Gc content from 0% to 30%, using dry and wet methods, at a medium density (Dr = 50%) and a range of normal stresses (σn = 100–300 kPa). The experimental findings provide remarkable trends. For dry pluviated specimens, an increase in fines content led to a decrease in the shear strength of the mixtures. Conversely, the wet deposited specimens exhibited an opposite tendency, where higher fines content induced larger shear strength. Notably, the incorporation of gravel substantially improved the mechanical performance of the sand mixtures, regardless of the preparation method employed. Dry pluviated specimens generally exhibited higher shear strength than that of the wet deposited ones for the same Fc/Gc. A developed set of equations has been suggested to predict the strength-dilatancy relationships for all-tested materials. These equations take into account the impacts of fines and gravel contents and both specimen preparation methods.

Research on the Configuration of Multi-Component Solid Waste Cementitious Materials and the Strength Characteristics of Consolidated Aeolian Sand

Developing green, low-carbon building materials has become a viable option for managing bulk industrial solid waste. This paper presents a kind of all solid waste cementitious material (SWCM), which is made entirely from six common industrial wastes, including carbide slag and silica fume, that demonstrate strong mechanical properties and effectively stabilize aeolian sand (AS). Initially, we investigated the mechanical strength of waste-based cementitious materials in various mix ratios, focusing on their ability to stabilize river sand (RS) and aeolian sand. The results show that it is necessary to use alkaline solid waste carbide slag to provide a suitable reaction environment to achieve the desired strength. In contrast, the low reactivity of coal gangue powder did not contribute effectively to the strength of the cementitious material. Further orthogonal experiments determined the impact of different waste dosages on the strength of stabilized AS. It was found that increasing the amounts of carbide slag, silica fume, and blast furnace slag powder improved strength, while increasing fly ash first increased and then decreased strength. In contrast, higher additions of desulfurization gypsum and coal gangue powder led to a continuous decrease in strength. The optimized mix is carbide slag—desulfurization gypsum—fly ash—silica fume—blast furnace slag powder in a ratio of 4:2:2:3:3. The experimental results using SWCM to stabilize AS indicated a proportional relationship between strength and SWCM content. When the content is ≥20%, it meets the strength requirements for road subbases. The primary hydration products of stabilized AS are C-(A)-S-H, AFt, and CaCO3. Increasing the SWCM content enhances the reaction degree of the materials, thereby improving mechanical strength. This study highlights the mechanical properties of cementitious materials made entirely from waste for stabilizing AS. It provides a reference for the large-scale utilization of industrial solid waste and practical applications in desert road construction.

Eco-Friendly 3D-Printed Concrete Using Steel Slag Aggregate: Buildability, Printability and Mechanical Properties

Utilizing steel slag aggregate (SA) as a substitute for river sand in 3D concrete printing (3DCP) has emerged as a new technique as natural resources become increasingly scarce. This study investigates the feasibility of using steel slag (SS) as fine aggregate for 3DCP. Ninety mixtures with varying steel slag aggregate-to-cement ratios (SA/C), water-to-cement ratios (W/C), and silica fume (SF) contents were designed to study the workability and compressive strength of the 3D-printed concrete. Additionally, the actual components were printed to evaluate the printability of these mixtures. The experimental results indicate that it is feasible to fully employ SA in concrete for 3D printing. Mixtures with slump values ranging from 40 to 80 mm and slump flow values varying from 190 to 210 mm are recommended for 3D printing. The optimal mix is determined to have SA/C and W/C ratios of 1.0 and 0.51, respectively, and an SF content of 10% by cement weight. A statistical approach was utilized to construct the prediction models for slump and slump flow. Moreover, to predict the plastic failure of the 3D-printed concrete structure, the modified prediction model with an SA roughness coefficient of 4 was found to fit well with the experimental data. This research provides new insights into using eco-friendly materials for 3D concrete printing.

Recurrence interval of riverbed sand mining hotspots in the Mekong delta: Potential indications of unsustainable replenishment rates

Rampant and illegal river sand mining in the Vietnamese Mekong Delta (VMD) has led to substantial sediment losses and bank erosion. However, regulation of this issue remains a significant challenge due to insufficient monitoring and enforcement efforts, partly attributed to limited data and technology. To support an improved monitoring system in the VMD, this study investigates the spatiotemporal changes in sand mining hotspots and their underlying drivers. The recurrence intervals of sand mining boats were assessed from 2014 to 2020 using Sentinel-1A, and its association with riverbed incisions were examined from bathymetry field surveys between 2017 and 2020. Our results attest to sand mining intensification from 2015 to 2020, particularly in the upstream section of the VMD, where 70% of the activity was recorded. Not only was there an apparent increase in sand mining hotspots by 32.4%, but most hotspots recorded a recurrence interval of 2 years. This potentially indicates a minimal timeframe of sediment replenishment before the same locations become economically viable for further sand extraction. Additionally, a correlation was detected between sand mining hotspots and significant riverbed incisions, although the lack of spatial overlaps in some regions suggests other upstream influences like bank collapse and river damming. Our study, through the meticulous assessment of sand mining boat movement and river bathymetry data, ultimately sheds light on the potentially unsustainable scale of sand mining activities in the VMD. It aims to support informed decision-making and effective regulations that tackle excessive sand extraction amid the dynamic environmental challenges we face, while offering valuable insights to similar deltas worldwide.

Enhancing Concrete Performance with Waste Foundry Sand Using Ternary Blended Mixes of Ordinary Portland Cement, Silica Fume, and Ground Granulated Blast Furnace Slag

AbstractMineral admixtures play an important part in improving the strength characteristics of concrete. This manuscript presents the incorporation of silica fume (SF) and ground granulated blast furnace slag into the concrete mix to decrease the cement content and enhance the strength and concrete's durability. In addition, river sand deposits have started to dry up. Also, eco‐friendly disposal of industrial wastes acts as a major threat to industries. Hence, the use of waste foundry sand (WFS) and M‐sand (MS) as fine aggregate is attempted in this study. In the first phase of this research work, concrete specimens have been prepared by partially replaced cement with 0%, 10%, 20%, 30%, and 40% by Ground Granulated Blast Furnace Slag (GGBFS) and 0%, 5%, 10%, and 15% by SF to find their optimum replacements in Ternary Blended Concrete (TBC). In the second phase, concrete specimens replaced with 0%, 10%, 20%, 30%, and 40% by WFS for fine aggregate (MS) were prepared and found optimum usage of foundry sand in waste foundry sand concrete (WFSC). In the third phase, a ternary blended green concrete (TBGC) was prepared by partially replaced cement with 30% GGBFS and 10% SF and replaced MS with 30% WFS and conducted strength (flexural strength, compressive and split tensile strength) and durability (acid and sulfate attack) studies. The above combination was found to be a promising way for the development of environmentally friendly concrete.

3D Cementitious composites printing with pretreated recycled crumb rubber: mechanical and acoustic insulation properties

ABSTRACT Cementitious materials incorporating recycled crumb rubber have become a common sustainable resolution in diverse building environments to achieve various functions in terms of lightweight, ductility, as well as energy absorption. This study explored the 3D printed rubberised cementitious composites (3DPRC) in two aspects: examining the effects of crumb rubber pretreatment conditions on compressive properties; conducting experimental and numerical analysis on the acoustic dissipation characteristics of 3DPRC. Fine crumb rubber granules (3-5 mm) replaced 10%, 20%, and 30% of river sand in the composites. Uniaxial compression tests indicated that the compressive strength of 3DPRC decreased with the increase of crumb rubber content and introduced anisotropic behaviour. Impedance tube tests were conducted to evaluate the sound absorption and insulation capabilities of 3DPRC. An optimal Noise Reduction Coefficient (NRC) of 0.35 was achieved with 30% crumb rubber. The sound insulation properties depend strongly on the mass density and porosity of the 3DPRC. Additionally, it is proved that the volume of built-in air gap has positive effects on both sound absorption and insulation properties. The results from Finite Element Method (FEM) numerical simulations correlated well with experimental data, proving the efficiency of the simulation and validating the experimental results.

3D characteristic indicator analysis and comprehensive evaluation of manufactured sand particles used in high-performance concrete

Two-dimensional particle morphology indices face challenges in accurately depicting the characteristics of three-dimensional (3D) manufactured sand (MS), which does not effectively guide the selection of MS for high-performance concrete (HPC). This study aimed to obtain a quantified comprehensive evaluation of actual MS particle groups with specific gradations by thoroughly analysing 3D geometric characteristics. Two representative MS samples were selected for exploration, and river sand (RS) was used as the control. A random selection of sand particles was screened on six sieve levels ranging from 0.15 mm to 4.75 mm. Using X-ray computed tomography and associated image processing technologies, 3D models of these particles were generated, and MATLAB was used to extract their 3D morphology information. Subsequently, the change rules and validity of current 3D particle morphology indicators were examined, focusing on shape, angularity, and texture. Moreover, a comprehensive morphology index, Cm, was proposed by considering the effects of gradation and particle shape classification. The results showed that shape indices more accurately reflected particle characteristics, notably, a higher proportion of spheroid particles, a lower aspect ratio, and greater sphericity correlated with improved particle shape; contrary to traditional beliefs, the angularity index suggested that greater roundness did not necessarily equate to more rounded particles owing to the influence of the proportion of spheroid and cubic particles; meanwhile, texture indices showed minimal difference in the mean values of the 3D fractal dimension for the three types of sand. The proposed index Cm effectively differentiated the particle morphology states of the three sands, with higher Cm values indicating superior particle morphology. The smaller the difference between the Cm values of MS and RS, the better substitute of MS for RS.

The primary porosity heterogeneity characteristics of braided river sandbody and implications for predicting the current physical properties heterogeneities

Understanding the heterogeneity of reservoirs is crucial for enhancing the efficiency of hydrocarbon exploration and development. The primary porosity of samples from modern braided river sands and outcrops of braided river sandstone was calculated using a model previously proposed by the authors. The characteristic parameters (Vx) for calculating primary porosity are closely related to the architectural–elemental configurations (AEC), and the AEC of braided river sand bodies (BRSD) has apparent effects on the distribution of the primary porosity heterogeneities. Analysis of our results has established a simple primary porosity heterogeneity model of BRSD. The center of braided river channel and mid-channel bars have excellent strong primary petrophysical properties with high primary porosity exceeding 38%. The contact areas between the braided river channel and channel bars exhibit relatively low primary porosities of less than 33%. The area between the center and edge of the braided bars and channels displays medium primary porosities. The nonlinear correlation in the Q–Q plot of the primary porosity and present porosity of samples from BRSD in the Ahe Formation is mainly caused by chemical diagenesis. The present porosity heterogeneity of BRSD in the Ahe Formation is less influenced by compaction and cementation, it predominantly arises from the differential of dissolution. Q–Q plots attempt to correlate the geological information from an individual sample with the heterogeneity of present porosity in BRSD. In addition, by utilizing Q–Q plots of the primary and current petrophysical properties of the sand body, the relative extent of heterogeneity modification caused by different diagenetic processes can be assessed. This assessment is crucial for modeling macroscopic models of physical properties during geological history periods.

Qualitative analysis of rivers sand sources (Silica sand, Ravi river sand, Indus river sand, and Jhelum river sand) for metal casting: a comparative study

Abstract Recent geological investigations revealed extensive use of Silica sand in Pakistan resulting in depletion of tectonic resources. Hence, it is important to explore cost-effective and alternative sources of sand for its applications. Also, Pakistan has a river network that provides river sand as a potential substitute for Silica sand. However, it is essential to systematically study and assess the potential applicability of river sand as an alternative to Silica sand. In this context, this study examined sand samples collected from various rivers in Pakistan to investigate their suitability for metal-casting molds. For that purpose, random samples were selected from major rivers in Pakistan for characterization by utilizing chemical composition analysis, microscopy, XRD, TGA-DSC (thermogravimetric analysis), clay content analysis, grain size distribution analysis, pH measurement, green and dry compression strength testing, shear strength testing, permeability analysis, shatter index analysis, compactibility testing, and Specific gravity measurement. The chemical composition analysis revealed that all types of sands contained over 90% SiO2 content. The mechanical tests demonstrated that river sand exhibited acceptable mechanical properties, with a moisture content ranging from 4.5-5%. The pH value of all the sands exceeded 7, making them suitable for casting purposes. These investigations suggest that river sand can be effectively utilized in casting applications by implementing pre-processing techniques and incorporating additives.

Exploring the rheological and mechanical properties of alkali activated mortar incorporating waste foundry sand: A comprehensive experimental and machine learning investigation

Alkali-activated materials, known for their economical and eco-friendly nature, are becoming popular as a viable substitute for traditional cement-based materials in the field of construction. This research thoroughly examines the intricate rheological characteristics and compressive strength (CS) of alkali-activated mortar (AAM). It specifically explores the use of waste foundry sand (WFS) as an environmentally conscious and sustainable alternative to river sand. The addition of WFS significantly improves the CS of AAM, demonstrating 35 % enhancements at a 30 % sand replacement level. The rheological properties of customized AAM mixtures were targeted to achieve optimal use in 3D printing. The increasing replacement level of WFS in the matrix induced a non-linear reduction in yield stress (37 % decrease at 30 % replacement) accompanied by a concurrent rise in plastic viscosity (38 % increase at 30 % replacement). Considering the intricate interplay between rheological parameters and CS, AAM containing 15 % sand replacement exhibited optimal properties. Moreover, through rigorous experimentation, a comprehensive dataset of 64 samples was established by varying the amount of river sand, WFS, and water content in the mix. Machine learning models—including AdaBoost, decision tree, K-nearest neighbors, stochastic gradient descent, gradient boosting, random forest, neural network, gene expression programming, and support vector machine—were developed to predict CS, yield stress, and plastic viscosity of the AAM. Modeling errors, including MSE, RMSE, MAE, and MAPE, were falling in the acceptable limits. Specifically, most models demonstrated a high level of prediction having R2 > 0.90 across training and validation datasets. In conclusion, this study not only highlights the optimized properties of AAM but also validates the efficacy of various machine learning models in predicting crucial parameters for AAM formulation.