Mortar Aggregate Research Articles

Towards Sustainable Masonry Construction Through Natural Aggregate Replacement by Fine Recycled Aggregates in Cement–Lime Mortars

Sustainable development relies on the circularity in the built environment, which, in turn, includes recycling construction and demolition waste and using recycled materials. However, using fine recycled fractions is challenging, especially considering the requirements for new building applications. Yet, producing more widely applied recycled coarse aggregates usually leads to the simultaneous generation of recycled sand fraction, which contains many fines that pose potential problems. This work presents the direct incorporation of concrete and mixed waste-based recycled sand and recycled fines in masonry mortars, on the one hand, as a complete aggregate replacement and, on the other, only replacing the finest aggregate fraction. Such mortars are assessed based on the fresh and hardened mortar properties and are compared to natural aggregate-containing mortars. In the fresh state, the mortars with recycled fines and recycled sand required more mixing water to produce comparable consistency and workability. In a hardened state, mortars with recycled mixed waste sand and fines have demonstrated increased mechanical strength compared to natural aggregate mortars. In contrast, those containing recycled concrete aggregates and fines were inferior in that regard. This indicates the potential of using recycled mixed waste fractions to improve masonry mortar performance, although both types might be important in enhancing the sustainability of masonry construction.

Análise comparativa entre aderência à tração e resistência à compressão em argamassas produzidas com vermiculita expandida

In the construction industry, the performance of building elements is a pertinent topic for scientific research. Sustainability and concern for non-renewable natural resources have stimulated the search for alternative materials that have the potential to improve the properties of cement mortars. Although it is a material that is still rarely used as an aggregate in mortars, expanded vermiculite has interesting properties, with the potential to replace natural sand, reducing the environmental impact caused by its extraction. The aim of this study was to analyze, based on physical and mechanical characteristics, the reduction in environmental impact caused by replacing natural sand with expanded vermiculite as an aggregate in coating mortars. In this study, we analyzed the compressive strength and tensile bond strength of coating mortars produced from a 1:1:6 mix by volume and with 10, 20, 30, 40 and 50% replacement of natural aggregate with expanded vermiculite, comparing them with a reference mix. The experimental stage consisted of characterizing the aggregates, making the mortars and testing them in the fresh and hardened state. According to NBR 13281-1 (ABNT, 2023), the mixtures can be classified in terms of compressive strength as P3 (AN100, VE10, VE40 and VE50, with strengths between 2.5 and 4.5 MPa) and P4 (VE20 and VE30, with strengths between 4.0 and 6.5 MPa). Based on the same standard, the mixtures can be classified in terms of tensile bond strength as RA1 (AN100, VE40 and VE50, for strength greater than or equal to 0.2 MPa) and RA2 (VE10, VE20 and VE30, for strength greater than or equal to 0.3 MPa). It should be noted that the results for the intermediate traits VE20 and VE30, with compressive strengths between 4.0 and 6.5 MPa and tensile bond strengths greater than or equal to 0.3 MPa, can be classified as P4 and RA2 respectively. All the mixes complied with NBR 13749 (ABNT, 2013), which stipulates minimum values of 0.20 MPa for internal walls and 0.30 MPa for external walls. VE10, VE20 and VE30 were suitable for external cladding, while VE40 and VE50 were suitable for internal cladding. In these last two cases, the mixture stands out for meeting the standard and causing less environmental impact.

Converting Iron Mine Tailings into Composite Aggregates for Ultrahigh-Performance Mortar

Converting Iron Mine Tailings into Composite Aggregates for Ultrahigh-Performance Mortar

Macro-Mesoscopic Failure Mechanism Based on a Direct Shear Test of a Cemented Sand and Gravel Layer

In order to explore the influence of different layer treatment methods on the macro- and meso-mechanical properties of cemented sand and gravel (CSG), in this paper, the shear behavior of CSG material was simulated by a three-dimensional particle flow program (PFC3D) based on the results of direct shear test in the laboratory. In shear tests, untreated CSG samples with interface coating mortar and chiseling were used, and granular discrete element software (PDC3D 7.0) was used to establish mesoscopic numerical models of CSG samples with the above three interface treatment methods, in order to reveal the effects of interface treatment methods on the interface strength and damage mechanism of CSG samples. The results show that, with the increase in normal stress, the amount of aggregate falling off the shear failure surface increases, the bump and undulation are more obvious, and the failure mode of the test block is inferred to be extrusion friction failure. The shear strength of the mortar interface is 40% higher than that of the untreated interface, and the failure surface is smooth and flat under different normal stresses. The shear strength of the chiseled interface is 10% higher than that of the untreated interface, and the failure surface fluctuates significantly under different normal stresses. Through the analysis of the fracture evolution process in the numerical simulation, it is found that the fracture of the sample at the mortar interface mainly expands along the mortar–aggregate interface and the damage mode is shear slip. However, the cracks of the samples at the gouged interface are concentrated on the upper and lower sides of the interface, and the damage mode is tension–shear. The failure mode of the samples without surface treatment is mainly tensile and shear failure, and the failure mode gradually changes to extrusion friction failure.

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

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

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

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

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

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

Expanded Polystyrene/Tyre Crumbs Composites as Promising Aggregates in Mortar and Concrete.

A composite material comprising expanded polystyrene (EPS), granulated tyre rubber (GTR), and a compatibilizer is demonstrated as a possible replacement for fine and coarse agglomerates in mortar and concrete systems, respectively. Two different polymer blending processes (solvent/low shear blending and melt/high shear blending) are used, and the resulting composite material utilized as aggregate to replace sand and cement for mortar and concrete block development. Critical properties such as workability, compressive and flexural strengths, water absorption, bulk density, and porosity are measured before and after aggregate replacement. The novel composite material led to significant improvements, boosting compressive strength by 7.6% and flexural strength by 18% when sand was replaced and further increasing compressive strength by 22.2% and flexural strength by 5.26% with cement replacement. However, a decrease in compressive and flexural strength was observed when plain EPS and plain GTR were used separately as aggregate replacements. This work proposes a pathway for the successful reincorporation of difficult-to-recycle materials such as EPS and GTR, otherwise destined for landfill, back into the supply chain for the construction industry. Moreover, this research represents the first reported work where the overall properties of mortar have surpassed those of standard mortar when substituted with recycled EPS or GTR.

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

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

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

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

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

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

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

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

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

Characterization and Classification of Mortars for Underlayment with PCR-PET Artificial Aggregate in Partial Replacement of Natural Sand Aggregate in the Mix

This study investigated the feasibility of using Post-Consumer Recycled Polyethylene Terephthalate (PCR-PET) as an alternative aggregate in mortar for civil construction, aiming to evaluate its properties and impact on the sector's sustainability. Compressive strength, substrate adhesion, workability, and water retention tests were conducted on mortars with PCR-PET addition, and the results were compared with conventional mortars and the requirements of the ABNT NBR 13281 standard. The results showed that adding PCR-PET to mortars led to a slight reduction in compressive strength and substrate adhesion; however, the values remained within the limits set by the standard. Workability and water retention of mortars with PCR-PET were similar to conventional mortars. This study contributes to the field of civil construction by presenting PCR-PET as a viable and sustainable alternative for the use of plastic waste in civil construction, contributing to the reduction of demand for natural resources and waste generation. However, further studies are needed to assess the mechanical behavior and durability of mortars with PCR-PET in the long term, as well as their complete environmental impact.

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

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

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

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