Mortar Aggregate Research Articles

Prediction of the rheological properties of mortar compounded with desert sand and Pisha sandstone ceramic sand based on density-form coupling

Ordos, China has a large amount of environmentally hazardous Pisha sandstone and desert sand. Pisha sandstone ceramic sand and desert sand can be compounded to prepare light and fine aggregates, which are often used in construction mortar. However, it is unknown how the density and particle shapes of light and fine aggregates affect their rheological properties. In this study, we establish a predictive model for the rheological properties of light and fine aggregate mortar, using the Krieger-Dougherty and Chateau-Ovarlez-Trung models as a basis. First, density and particle morphology parameters are introduced and modified for light and fine aggregate mortars. Then, the morphological parameters of different types of fine aggregate particles were measured using image analysis techniques. This showed that the roundness of the particles decreases with decreasing density, and both the roughness and the aspect ratio increase. A regression model between the particle morphology parameters and characteristic viscosity was accordingly developed. The rheological properties of different types of mortars were examined. We find that as the particle density decreases, the yield stress and plastic viscosity decrease continuously, showing shear thickening behavior. Based on the coupled density-form effect, a modified Krieger-Dougherty model and Chateau-Ovarlez-Trung model are proposed. These proposed models result in more accurate predictions of plastic viscosity and yield stress for light and fine aggregate mortars.

Pore structure and mechanical characteristics of CRS mortar based on NMR and fractal theory

Crushed rock sand (CRS) is increasingly used as a substitute for natural sand in mortar aggregates, and the mixing ratio and pore structure of CRS mortar affect its macromechanical performance. This study used five CRSs with different grain sizes to formulate five single-graded and their synthetic-graded mortars with the same paste film thickness by regulating the aggregate-cement ratio. Utilizing nuclear magnetic resonance (NMR) technology in conjunction with fractal theory, the evolution characteristics of pore structure parameters (porosity, pore fractal dimension and permeability coefficient) and mechanical properties are analyzed, and the correlation between pore structure and mechanical parameters is established. The results indicate that, at a constant paste film thickness, the total porosity (φtotal) of the single-graded mortars increases with the augmentation of the aggregate-cement ratio, while the total pore fractal dimension (Dtotal), compressive strength (σc), and compressive modulus (Ec) progressively decrease. The complexity of the pore structure in mortars tends toward homogeneity with an increasing number of distinct pore structures. The synthetic-graded mortar exhibits a higher pore structure fractal dimension than the single-graded mortars, indicative of a more intricate pore structure. Furthermore, a significant correlation is observed between the pore structure fractal dimension of the mortar and its porosity, permeability coefficient, σc, and Ec, revealing the interplay among the internal pore structures of the material and their control over the macroscopic properties.

Effect of oxidation of End-of-Life Tire Rubber as Aggregate Substitute in Cement Mortars.

In this paper the possible use of end-of-life tire rubber as a substitute for aggregate in cement mortars was explored. The aim of this paper was to investigate the effect of rubber surface modification by acidic treatment on the final properties of mortars. In fact, through treatment with sulfuric acid at moderate concentrations, a significant improvement in rubber wettability and interaction with cement has been observed. The compressive strength of mortars containing 15%w treated rubber as a replacement of natural aggregate is comparable to those of standard mortars. This suggests that surface modification of rubber plays a very important role in the possible integration of end-of-life tire rubber in mortar and concrete. The results presented in this paper confirm that recycling in mortar and concrete is a promising way for improving rubber waste management and sustainable innovation in the construction industry.

New database of sustainable solid particle materials to perform a material-based design for a thermal energy storage in concentrating solar power

Renewable energies have surged worldwide, aiming to mitigate greenhouse gas emissions and reduce dependence on fossil fuels. Concentrated solar power (CSP) with thermal energy storage (TES) emerges as a viable alternative to bridge the gap between renewable energy generation and consumption. However, existing CSP plants face a significant challenge in optimizing performance due to the operational temperature limitations of solar salt. While alternative materials, such as solid particles for sensible heat storage in solar towers exceeding 600 °C, have been proposed, the crucial aspect revolves around selecting a new alternative sustainable low-cost material for use as a TES media. This article investigates the optimization of CSP-TES systems by evaluating alternative sustainable low-cost materials sourced from several sectors such as the mining or metallurgical industry, municipal solid wastes, or demolition wastes. The materials, either used in their original form or formulated into aggregates for mortars, underwent thorough a property comparison focused on thermal, physical properties, and cost. With this data, a database was created using the Constructor software from ANSYS and integrated with the Selector software from the same company that provides instrumental for the creation of a comprehensive repository of sustainable materials, providing a database that serves as a practical reference guide for optimizing the selection of sustainable materials as TES in CSP plants. Then, a baseline could be established for selecting a sustainable material for a specific design, considering the properties of the materials. This methodology consists of redesigning and adapting the system according to the material, and it is known as the Materials-Based Design (MBD) process.

Dynamic properties of mortar with oyster shell sand replacement

With the rapid expansion of construction engineering, the demand for traditional materials, particularly natural river sand, has surged, resulting in excessive resource exploitation and significant ecological damage. In response, the use of waste oyster shells as a sustainable alternative for fine aggregates has gained attention. However, limited research has been conducted on the dynamic properties of mortar with this substitution. This study explores the potential of using crushed oyster shell sand (OSS) as fine aggregates in mortar. A series of Split Hopkinson Pressure Bar (SHPB) tests under different gas pressures (pg) (0.2, 0.3, and 0.4 MPa) were carried out on mortar samples with five OSS replacement ratios (Rr) (0%, 20%, 50%, 80%, and 100%), using a water-to-cement ratio of 0.55. The results showed that when the OSS replacement rate (Rr) increased from 0 to 20%, there was a significant increase in peak stress (σmax) and elastic modulus (E), attributed to the filling effect of OSS, which enhanced the absorbed energy (Eab) and strength contribution rate (SCR). However, at Rr above 20%, a sharp decline in σmax and E was observed, primarily due to porous characteristics of OSS. Correspondingly, Eab decreased, reducing the impact resistance of mortar. Moreover, the negative SCR suggests detrimental effects on mortar integrity at higher OSS Rr levels. Predictive relationships for peak stress and elastic modulus across different replacement ratios were established in this study, providing a foundational reference for the design and assessment of the dynamic mechanical response of structures incorporating OSS.

Investigating the impact of foundry by-product sand as an activator on workability improvement and strength development in alkali-activated blast furnace slag mortar

The substitution of alkali-activated furnace slag significantly reduces the necessity of cement manufacture and mitigates the continuous growth of carbon emissions. In addition, it shows superior mechanical properties compared to traditional concrete materials. However, rapid setting issues hinder its widespread applications. This study investigated the innovative use of zero-carbon waste sodium silicate-bonded sand as a substitute for the fine aggregate and sodium silicate in traditional alkali-activated blast furnace slag mortar. The primary objective is to analyze the impact of waste sodium silicate-bonded sand on the workability and mechanical properties of the mortar. The key properties such as flowability, setting time, temperature measurement, compressive strength, and microstructural were analyzed to determine the improvement in workability and the strength development of alkali-activated blast furnace slag mortar resulting from the use of waste sodium silicate-bonded sand. The research showed the integration of waste sodium silicate-bonded sand results in an eco-friendly and cost-effective material, which addresses limitations in traditional activated blast furnace slag mortars. The finding revealed that substituting fine aggregate and sodium silicate with waste sodium silicate-bonded sand significantly improved the mechanical and workability properties of alkali-activated mortars. Notably, the compressive strength of mortars incorporating waste sodium silicate-bonded sand exceeded that of traditional Portland cement and effectively mitigated rapid setting issues. In addition, this approach led to an environmentally friendly mortar with satisfactory workability. The research emphasizes the practical benefits of utilizing waste sodium silicate-bonded sand and offers new insights into its effects on mortar performance. This has provided more details for future exploration and refinement in the field of alkali-activated materials.

Can mussel shell waste optimize cement and air lime mortars hygrothermal performance?

Mussel shells used as aggregates for mortars have flaky and irregular particles, which significantly increases the pore volume. This leads to the identification the microstructure of mussel shell mortars as a light and porous composite, which could have good hygrothermal properties. In the present study, the density and thermal properties are assessed on cement and air lime mortars, each with three replacement percentages of replacement of conventional sand by mussel shell sand (25 %, 50 % and 75 %), are evaluated and compared with their respective baselines (0 % replacement). Thermal conductivity measurements are also carried out on different loose fractions of the mussel shell aggregate to understand the behaviour of this material without binder matrix. Finally, adsorption and desorption cycles at 80 % and 50 % relative humidity are carried out on loose aggregate fractions and on the eight mortars. The results are very positive for the mussel shell mortars, as it can be concluded that the use of mussel shell aggregates improves the thermal performance and the potential moisture buffering capacity of both cement and air-lime coating mortars.

Studying of Mechanical Behavior of Waste Materials Modified Cement Mortar

Large-scale environmental problems have been triggered by ceramic tiles from demolished buildings and animal bone waste. Therefore, optimizing their potential for reuse and recycling is an important goal of sustainable solid waste management. The primary objective of this study is to evaluate the feasibility of partial replacement of the fine aggregates in cement mortar with a combination of natural animal bone powder and industrial waste materials which is wall tiles ceramic powder. This study measures thermal and mechanical characteristics. Recycling construction waste is one of many ways to deny waste material from entering landfills and create new eco-friendly material that reduces energy consumption in buildings. Modified mortar cement specimens with 5% up to 25% mixtures were combined using a 1:3 ratio and a 0.5 W/C ratio to see how the ratios would affect the material’s properties. The addition of a superplasticizer boosted the cement mortar’s workability and compressive strength. The compressive strength, flexural strength, density, and thermal conductivity were evaluated for each mortar mixture ratio. Results showed that compared to regular cement mortar, cement mortar combined with 20% bone and ceramic powder wastes reached the optimal replacement percentage. Compressive strength increased by 54% and flexural strength by about 67%. At the 28-day mark, thermal insulation was lowered by 25%.It is concluded from this study that it is possible to use bone waste as a natural material with ceramic waste as an industrial material to modify the insulation and mechanical properties of cement mortar.

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.

Mechanical, electrical, and piezoresistive properties of modified conductive recycled fine aggregate smart mortar

The application of recycled fine aggregates (RFA) in smart conductive mortar is of great significance for conserving natural resources and protecting the environment. However, the high water absorption and microstructural defects of RFA limit its widespread use in smart conductive mortar. This study employs an agar gel impregnation treatment containing graphite particles to improve the properties of RFA. The resulting modified conductive recycled fine aggregate (M-RFA) exhibited a 2.8 % reduction in water absorption. The workability, mechanical properties, electrical properties, and self-sensing capabilities of the modified recycled fine aggregate mortar (M-RFAM) were studied. It was found that the workability and mechanical properties of the smart conductive mortar prepared with M-RFA were slightly reduced but remained within acceptable ranges (28-day compressive strength greater than 33 MPa). At the same time, it achieved low resistivity and high strain-sensing sensitivity, with the highest strain-sensing sensitivity being 61.9 (30 times higher than ordinary strain gauges). The influence of loading rate and moisture content on the self-sensing ability of conductive mortar was also investigated, revealing a positive correlation between moisture content and stress-sensing ability. Furthermore, the study found that factors such as AC frequency, curing age, moisture content, and temperature significantly affect resistivity. These factors should be considered in practical applications and further research.

Evaluation of Iron Ore Tailings From the Fundão Dam Failure in Mariana-MG As A Partial Substitute For Conventional Fine Aggregates in Cement Mortars

Evaluation of Iron Ore Tailings From the Fundão Dam Failure in Mariana-MG As A Partial Substitute For Conventional Fine Aggregates in Cement Mortars

Use of Milled Acanthocardia tuberculate Seashell as Fine Aggregate in Self-Compacting Mortars.

This study focuses on the feasibility of using ground Acanthocardia tuberculate seashells as fine aggregates for self-compacting mortar production. The obtained results show a promising future for coastal industries as their use eliminates waste products and improves the durability of these materials. The use of Acanthocardia tuberculate recycled aggregate, in terms of durability, improves the performance of all mixes made with seashells compared to those made with natural sand, although it decreases workability and slightly reduces mechanical strength. Proper mix design has beneficial effects, as it improves compressive strength, especially when the powder/sand ratio is 0.7. Three replacement ratios based on the volume (0%, 50%, and 100%) of natural limestone sand with recycled fine aggregate from Acanthocardia tuberculate seashells, and three different dosages modifying the powder/sand ratio (0.6, 0.7, and 0.8), were tested. The fresh-state properties of each self-compacting mixture were evaluated based on workability. The mineralogical phases of the hardened mixtures were characterised using X-ray diffraction, thermogravimetry, and differential analyses. Subsequently, the mechanical and durability properties were evaluated based on the compressive and flexural strengths, dry bulk density, accessible porosity for water and water absorption, drying shrinkage, mercury intrusion porosimetry, and water absorption by capillarity. Therefore, the use of Acanthocardia tuberculate seashells in cement-based systems contributes to circular economy.

Mechanical characteristics and microscopic mechanism of polypropylene fiber modified recycled road solid waste fine aggregate mortar

Recycled fine aggregate (RFA) is a recycled building material obtained by crushing and screening waste concrete, which is the main raw material for producing recycled aggregate mortar (RAM). However, due to the defects of RFA such as many cracks, high porosity and large fragmentation index, RAM has problems such as low compressive strength and poor flexural strength, which limits its large-scale application in mortar engineering. In this paper, a series of experiments were carried out to verify that the addition of polypropylene fiber (PPF) improves the mechanical strength of RAM. Four lengths (3 mm, 6 mm, 9 mm, 12 mm) and three dosages (0.3 %, 0.6 %, 0.9 %) of PPF were added, and their effects on the compressive strength and flexural strength of RAM were studied. The test results show that the addition of PPF can improve the compressive strength and flexural strength of RAM and increase the toughness of RAM. The addition of PPF with 0.6 % dosage and 12 mm length can increase the compressive strength of RAM by 57 % and the residual strength by 73 %. The addition of PPF with 0.9 % dosage and 12 mm length can increase the flexural strength of RAM by 58 % and the fracture energy by 163 %. Scanning electron microscopy (SEM) results show that PPF can improve the microstructure of RAM. The effective bonding between the matrix and PPF is observed, which increases the mechanical strength of RAM. In addition, PPF is pulled out and broken, proving that PPF effectively plays its bridging and stretching role in the matrix. Moreover, a prediction model for the effect of PPF length and dosage on the compressive strength and flexural strength of RAM is proposed, which can provide theoretical basis for practical engineering and reference for related researches. This study proposes a negative carbon method for applying road solid waste to engineering mortar, which can provide theoretical basis for practical engineering and reference for related research.

Pore structure evolution of mortars with manufactured sand aggregate under the influence of aggregate size and water saturation environment

To investigate the effect of aggregate size on pore structure and pore evolution in water saturation of manufactured sand aggregate (MSA) mortars, five MSA mortars with small range of aggregate sizes were prepared and their pore characterization were monitored over 365 days. The findings showed that an increased surface volume ratio (SVR) leads to an increase in total and macroporous porosity, and three pores with different connectivity were quantified using double T2 cutoff method. Moreover, continued hydration by unhydrated cement caused an increase in micropores during the initial stage of service in a water-saturated environment for 365 days, and an increase in macropores at the later stage as a result of enhanced hydraulic solvation, furthermore, solvation was more significant in the mortar with larger SVR to the point where it eventually produced pores larger than 100 μm. This research would provide guidance for the durability evaluation of cement mortars.

Enhancing the interfacial properties of recycled rubber aggregate mortars through surface modifications with graphene oxide coating

This study explores the potential application of waste rubber (WR) as sustainable recycled rubber aggregates (RRA) in the construction sector. A layer of graphene oxide (GO) was coated on RRA through multiple surface modification techniques, aiming to enhance the interfacial properties in RRA mortars. The C-S-H phases were first tailored through chemical synthesis to better understand the nucleation and growth of hydration products with the presence of GO. Subsequently, a 180 ± 10 nm-thick GO coating was attached to the RRA surface through surface treatment with sodium hydroxide solution, silane coupling agent, and GO suspension. In addition, the mechanical strength, damping performance, water absorption, chloride resistance, and microstructural properties of cement mortars prepared with RRA were further assessed. It was found that the GO coating significantly improves the bonding between RRA and the cementitious matrix due to its hydrophilicity and nucleation effects, which locally facilitate the cement hydration at interfaces. The cement mortars produced with surface-modified RRA exhibit promising high-damping characteristics, accompanied by improved durability and mechanical performance over those prepared with untreated RRA.

EXAMINING THE USE OF MARBLE WASTE AS A SUBSTITUTE OF CONVENTIONAL MATERIALS IN CONCRETE: A BRIEF REVIEW

For decades studies have investigated using marble waste as a partial replacement for conventional materials in concrete. This review examines the findings on substituting marble waste for coarse aggregate, fine aggregate, and cement. The studies accessed suggest that replacing up to 50% of coarse aggregate with marble waste can improve the concrete's mechanical properties and durability. Using marble waste for up to 20% of fine aggregate in concrete, mortars, and self-compacting concrete improves workability, compressive strength, and sustainability. Additionally, substituting up to 10% of cement with marble dust helps reduce cement consumption and the environmental impact of concrete production. The benefits of using marble waste include better mechanical properties, cost savings, and a smaller ecological footprint. Despite the numerous benefits, gaps in research persist, particularly in long-term performance studies, standardized testing methods, and comprehensive life cycle assessments. This review highlights the potential of marble waste as a valuable resource in the concrete industry and underscores the need for further research to optimize its use and fully realize its benefits in sustainable construction practices.

Evaluation of MSA mortar pore structure characteristics in water-saturated curing environment based on Talbot gradation theory

To investigate the impact of aggregate gradation on the pore structure of manufactured sand aggregate (MSA) mortar and its fractal characteristics under water-saturated curing conditions. The static pore structure characteristics of the pore structure of MSA mortar with 10 aggregate gradations were explored. The analysis is based on the Talbot gradation theory, the NMR technique, and fractal theory. The surface area and roughness of aggregate particles contribute to a reduction in the porosity of MSA mortar. The aggregate gradation is quantified using the Talbot index. The correlation characteristics and intrinsic relationships between Talbot index and different pore structure parameters, such as total porosity, pore gradation, pore fractal dimension and permeability of MSA mortar, are analyzed. Two pore division methods are employed to explore the interrelationships among pore types, fractal dimensions and Talbot index. Additionally, A correlation model between Talbot index and permeability is developed to investigate the intrinsic correlation of parameter variations from a microscopic perspective. It is found that aggregate gradation is optimal with a Talbot index of 0.4, leading to the highest number of micropores and the lowest number of larger pores, thereby enhancing resistance to seepage and dissolution. Furthermore, The contribution of pore size, content and type to permeability varies with different aggregate gradations. Overall, this study serves as a valuable guide for the design and durability evaluation of mortar concrete projects in water-saturated curing environments.

Investigation of Conditions for Using Mass-Produced Waste Glass as Sustainable Fine Aggregate for Mortar

To address the environmental issues arising from the growing scarcity of natural fine aggregates (NFA) and landfilling of waste glass, research is being conducted globally to utilize waste glass as a sustainable fine aggregate. However, contradictory results have been obtained regarding the effect of the type of waste glass and the physical properties of waste glass fine aggregate (GFA) on concrete, making it challenging to promote the use of GFA in concrete. Therefore, to promote the use of GFA in concrete, it is necessary to examine it under field conditions, such as mass-production processes or real-scale concrete applications. This study introduced a mass-production process for GFA, and the effect of mass-produced GFA on mortar was evaluated. The fine aggregate properties (particle aspect ratio, crushing rate, and solubility) of the GFA and the effects of color, content, and particle size on the mortar properties (compressive strength, flexural strength, and ASR expansion behavior) were analyzed, along with the results reported in previous studies. Consequently, the high aspect ratio and microcracks in the particles of mass-produced GFA led to an increase in the strength reduction and ASR expansion of the mortar. These effects appear to be particularly severe for transparent GFA. Overall, this study proposed the content of GFA within 20% or the replacement of fine particles (< 500 μm) in NFA as a condition for sustainable fine aggregate.

Utilizing Edge-Oxidized Graphene Oxide to Enhance Cement Mortar's Properties Containing Crumb Rubber: Toward Achieving Sustainable Materials.

Scrap tires have become one of the most serious environmental issues worldwide in recent years. Exploiting this scrap has caught the attention of researchers in their efforts to conserve the environment. From a structural engineering materials perspective, a partial fine aggregate in cement mortar can be replaced by crumb rubber produced from scrap tires. This research mainly emphasizes the role of adding 0.1% edge-oxidized graphene oxide EOGO (by the weight of cement) in enhancing the properties of cement mortars containing 5%, 10%, and 15% of crumb rubber (by sand replacement). Cube and prism specimens were employed to investigate compressive and flexural strengths at 7- and 28-day curing ages. A porosity test was also conducted after 28 days of curing. In addition, a scanning electron microscopy (SEM) test was performed to investigate the effect of incorporating EOGO on the interfacial transition zone (ITZ). Results showed an enhancement of the mechanical properties of cement mortar, including compressive and flexural strengths, with the inclusion of EOGO in the mixes. The findings demonstrated that adding EOGO can improve the mechanical properties of mixes containing crumb rubber particles. Specifically, the mortar mix with 0.1% EOGO and 5% crumb rubber exhibited better performance compared with the virgin mix without rubber particles. Therefore, crumb rubber is viable for use as a sand replacement when EOGO is included.

Correlation between destructive and non-destructive evaluation to study of plastic waste aggregate mortar: a case study of mechanical proprieties

Non-destructive evaluation using ultrasonic pulse velocity (UPV) testing has extensive applications in the cement materials industry. Ultrasonic pulse velocity (UPV) test is accepted as alternative to destructive testing to determine the compressive strength, dynamic modulus of elasticity, and Poisson’s ratio, which are needed for structural design. In modern construction technology, the use of Plastic waste (PW) as a partial replacement to natural aggregates in a mortar mix is growing in popularity primarily because it reduces the initial capital cost of raw materials and the associated conservation in environment. In this regard, this study explains the correlations between mechanical proprieties, and UPV tests for mortar contains 25%, 50%, and 75% of waste aggregate of plastic. Mortar based on Plastic Waste (MPW) specimens were tested by direct, semi-direct, and indirect UPV. UPV measurements can be effectively used to determine the dynamic modulus of elasticity and Poisson’s ratio of Mortar based on Plastic Waste MPW. The dynamic elastic modulus and the Poisson’s ratio decreases for the same mortar composite when at increasing PW content. Thus, the incorporation of PW particles into the cement matrix confirms the capacity of composites to reduce the sound intensity and damp vibrations inside the composites. The results of this study will be significant for non-destructive evaluations of MPW, while additional recommendations for future studies are presented at the end of the paper.