Performance Of Mortar Research Articles

Optimizing Lime Mortar Performance: A Comprehensive Study on Mechanical and Durability Improvements with Palm Jaggery and Gallnuts

Optimizing Lime Mortar Performance: A Comprehensive Study on Mechanical and Durability Improvements with Palm Jaggery and Gallnuts

Properties and Mechanical Performance of Cement Mortars Incorporating Coffee Grounds Residues

Properties and Mechanical Performance of Cement Mortars Incorporating Coffee Grounds Residues

A mesoscopic numerical analysis method for evaluating the electromagnetic transmission performance of cement mortar with varying sand particle sizes and content

This paper explores the impact of sand content and particle size on the electromagnetic transmission performance (ETP) of mortar samples. This study involves designing mortar samples with a water-cement ratio of 0.4 and varying sand volume content from 0 % to 50 %. Additionally, a mesoscopic finite element model is established to analyze the electromagnetic transmission behavior. The findings indicate that the particle size and content of sand influence the multiple reflections behavior of electromagnetic waves, while the particle size of sand has almost no effect on the electromagnetic transmission coefficient and dielectric response. Although sand enhances the ETP of cement paste, its impact is limited. Furthermore, the study reveals that the distribution of the electromagnetic field remains continuous regardless of sand particle size or content, and is unaffected by the differing dielectric properties of sand and cement paste phases. However, the induced current generated by sand and other phases differs, leading to noticeable variations in dielectric loss. Mesoscopic simulation results clearly demonstrate that cement paste is the primary contributor to electromagnetic energy loss.

A comparative study on the bonding performance of an admixed repair mortar and high-strength flowable micro-concrete with substrate: Considerations on the physico-mechanical compatibility

The physical and mechanical properties of repair mortar (RM), incorporating a multipurpose hybrid admixture and a high-strength concrete matrix phase known as micro-concrete (MiC), have been experimentally investigated. The flexural and compressive strengths, as well as the modulus of elasticity of each mixture, were tested at 7 and 28 days. The dimensional stability of prismatic bar specimens under dry and water-saturated conditions was monitored over a period of 56 days. The thermal coefficient of expansion for each repair material was determined, and the risk of thermal cracking was evaluated. Additionally, the bonding performance of admixed repair mortar and micro-concrete with substrate mortar (SM) was assessed using a modified slant shear test setup. The influence of surface roughness on slant shear strength was also studied. The compatibility of each mix design with substrate mortar was quantified and compared using a “physico-mechanical compatibility” based proximity comparison criterion. The proposed methodology can be used to monitor the compatibility and bonding potential of a repair material for a given substrate. Test results and analysis indicated that the admixed RM, with lower compressive/tensile strength ratio, performed better than MiC in terms of substrate compatibility.

Effect of particle size and replacement ratio on mechanical performance of cementitious mortar containing ground recycled acrylonitrile butadiene styrene (GRABS) waste plastics

While waste plastics have been used as a natural sand aggregate replacement in cementitious mortar as a sustainable option to mitigate global accumulation of plastic waste in landfills, fundamental mechanical properties like compressive, tensile, and shear must be known to advance design and practical application of these cement-concrete composites as suitable building construction materials. Experimental testing is conducted to reveal to what extent the cementitious composite properties are altered, thereby influencing their overall mechanical performance, when both ungraded and graded ground recycled acrylonitrile butadiene styrene (GRABS) plastic are employed as substitutes for natural aggregates. The novelty of this research lies in its pioneering investigation to quantify the effects of varying particle sizes and volume fractions of waste plastics acquired through mechanical recycling and their influences on the mechanical properties of mortars containing plastics as a composite material. The results from fresh and hardened material properties are compared to conventional mortar properties to examine the impact of various GRABS particle sizes and volume fractions on the overall material strength. While replacing sand with waste plastic generally reduced mechanical properties, the resulting mixes still met the minimum compressive strength (4060 psi [28 MPa]) as per ASTM C150 standards for Portland cement. Notably, graded plastic particles with sizes less than 0.024 in [0.6 mm] demonstrated an overall improvement in mechanical properties compared to ungraded particles. Failure mechanisms responsible for compressive, tensile, and shear damage development are discussed by analyzing the fracture surfaces, which provide insight into the intricate relationship between waste plastic size and distribution on the mechanical behavior of mortar. The findings indicate that GRABS waste plastics, when combined with sand at appropriate particle sizes and volume fractions, have the potential to create tailored mixes to meet minimum mix design standards for construction applications.

Influence of ground slag and dune sand behavior of binary and ternary cement

This study examines the effect of slag and dune sand replacement (binary and ternary) in cement production, focusing on key mechanical properties and chemical behavior, especially on fire loss and residual an insoluble examined at different curing times ranging from 2 to 210 days. The findings show that the addition of slag and dune sand powder significantly influences the mechanical and thermal properties of mortar mixtures replaced by slag the compressive strength increases up to 30% and a slight decrease up to 40 is observed %. Ternary mixes show improved long-term compressive strength, especially after 120, 210 days, although generally young strength is lower than control When binary and ternary are combined with high flexural strength, ternary mixes exhibit good long-term performance, especially in mixtures of 20-30% slag and 10% dune sand lime (ACHOURA, D and al. 2008). From a thermal perspective, the replacement of slag with dune sand lime reduces losses during combustion, indicating excellent thermal stability. The addition of dune sand lime increases the proportion of impervious residue, indicating stability and durability of the cement. Overall, the study concludes that the proper use of slag and dune sand lime especially in ternary mixes can significantly improve the long-term mechanical and thermal performance of cement mortars Thus these findings provide valuable insights for designing building materials with higher durability and strength to suit specific construction application applications.

The impact of spent fluid catalytic cracking catalyst on the selected mechanical and physical performances of cement mortars

This paper presents the results of research aimed for evaluating the impact of applicability of spent fluid catalytic cracking catalyst as a substitute of 20, 40, 60 and 80% of cement, by mass, in cement mortars on their selected mechanical and physical performances. It was demonstrated that substitution of 20% of cement mass with spent catalyst enhanced mortar’s compressive strength for 16.7%. Further addition of spent catalyst tended to decrease strength, whilst, simultaneously, rose the values of capillary absorption and water absorptivity because of deterioration of cement matrix structure, documented by SEM photos. Based on the research and literature data, it was proved that spent cracking catalyst might be a promising additive to cement in the amount not exceeding 40% of its mass considering its pozzolanicity

Development of geopolymer and cement-based shotcrete mortar: Impact of mix design parameters and spraying process

Shotcrete mortar is used in various construction works, including repair, tunneling, mining, and slope stabilization, among others. Traditionally, cement is used to produce shotcrete mortars with high viscosity, flowability, and early strength. Geopolymers (GP) have the potential to replace cement in shotcrete mortars, owing to their ability to reduce the material’s environmental footprint without compromising performance. This investigation assesses the feasibility of utilizing fly ash and blast furnace slag-based GP mortars produced with dune sand in shotcrete applications while comparing them to cement-based mixtures. The GP and cement-based shotcrete mortars were designed to have similar yield stress values. The evaluated properties included the initial flow, thickness layer, rebound material, rheological properties, setting time, compressive strength, ultrasonic pulse velocity, and pull-off bonding strength. Test results showed direct relationships between the yield stress and initial flow values, as well as between the buildup thickness and plastic viscosity, revealing that GP mortars were suitable for shotcrete applications, specifically those produced with flow values of 18.5 cm or less. GP mixtures produced with higher slag content than fly ash, higher sand content compared to binder, higher SH molarity, and lower solution content achieved higher buildup thickness owing to their higher viscosity. In the second phase, the performance of four mixes with different initial flows was assessed at various pumping flow rates and distances between the wall and machine pipe nozzle. The findings confirmed that these spraying parameters are crucial to improve the shotcrete performance of GP mortar with varying fresh behaviors.

Studies on the performance of alkali-activated aluminosilicate geopolymer mortar against exposure to acid, sulfate, and elevated temperature

An alkali-activated aluminosilicate is a group of materials that have the potential to reduce the carbon footprint of the construction industry. Several combinations of materials have been explored for producing alkali-activated aluminosilicate geopolymer mortars, emphasizing the need to understand their resistance to chemical attack and elevated temperatures to ensure long-term durability. The present study prepared fly ash-based alkali-activated aluminosilicate mortar using fly ash (FA) and ground granulated blast furnace slag (GGBS) without heat curing. Properties such as compressive strength and weight loss were evaluated after chemical attack and exposure to high temperatures (200° to 1000°), and compared with PC mortars. The result shows that fly ash and GGBS-based alkali-activated aluminosilicate mortar (AAAM) exhibit better resistance to chemical attack and high temperatures than conventional mortar. Specifically, after 180 days of acid exposure, PCM showed a mass loss of 5.06% and compressive strength loss of 85%, while AAAM had a mass loss of 2.88% and compressive strength loss of 71%. Sulfate exposure led to a mass gain of 55.77% for PCM and 27.35% for AAAM, with compressive strength losses of 55.77% for PCM and 27.35% for AAAM. Elevated temperatures (1000°) resulted in a compressive strength loss of 68% for PCM and 45% for AAAM. To substantiate these results, X-ray diffraction (XRD) and Fourier Transformation Infrared Spectroscopy (FTIR) were used to study the changes in the bonding behavior of C-A-S-H (Calcium-Aluminate-Silicate-Hydrate) and N-A-S-H (Sodium-Aluminate-Silicate-Hydrate) when exposed to chemical attack and elevated temperatures.

Improving the thermal and mechanical performance of cement-based mortars for reinforcing masonry structures: computational and experimental methods

Improving the thermal and mechanical performance of cement-based mortars for reinforcing masonry structures: computational and experimental methods

Impact of in-situ CO2 injection on natural and accelerated carbonation performance of aerial lime mortar

Aerial lime is a well-known carbonatable binder. To address some limitations of slow carbonation speed and low initial strength, this study proposes an internal carbonation technique for field-casting aerial lime mortar using in-situ CO2 injection. The technique was found to be significantly effective in accelerating the carbonation and strength development of the mortar. For the first 28 days, the mortars mixed with CO2 injection showed 1.25–1.68 times faster carbonation and 1.5–2.3 times higher compressive strength than the mortar mixed without CO2 injection. This improvement can be explained by the internal carbonation effect, which effectively refines the pore structure while providing a nucleation site for subsequent carbonation. The early refinement of the pore structure also increased later carbonation performance under both natural and accelerated conditions.

Effect of Enteromorpha-diatom adhesion on mortar performance

With the development of the marine economy, seawater is becoming more eutrophic. The risk of green tides from Enteromorpha is rising, which adversely affects the service of coastal infrastructure structures. To better evaluate the influence of algae on the long-term service performance of the structural concretes in coastal infrastructure, this study investigates the law of Enteromorpha-diatom attachment and growth on the mortar surface and its influence on the microstructure and durability of mortar. The results show that: 1) at 15 days, diatoms appeared on the surface of the mortar and biofilm appeared，the time period of adhesion and germination of Enteromorpha spores on the mortar surface was between 60 and 75 days. 2) Within 60 days, the spores released by the Enteromorpha preferentially germinate on the edges and in the pores of the mortar specimen, which can create micro-cracks on the mortar surface. Calcium carbonate may be involved in the metabolism of algae. 3) The pore size of the mortar surface gradually increases in the presence of bio-organic acids, which can accelerate the decrease of pH on mortar surfaces and reduce the resistance of mortar against chloride ions. This study confirms that green tide outbreaks may reduce the durability of cementitious materials, and provides a practical guide in the timing of protecting coastal infrastructure structures during the period of green tide outbreaks.

Study on the influence of early frost attack on the performance of cement mortar

The loss of strength and durability caused by early frost attack is the macro performance of internal microstructure deterioration. Understanding the influence mechanism of early frost attack at the micro level is necessary to avoid or minimize the early frost attack to macro performance. In this study, the influence of early frost attack on the strength, water sorptivity, chloride permeability, and microstructure of cement mortar was investigated. The fresh mortars were pre-cured for 10, 12, 14, and 16 h and then frozen at −10 °C for 7 days to simulate an early frost attack. After freezing, the standard curing (20 °C) was carried out until the testing. It is found that after standard curing of 28 days, the strength of early-frozen mortar can reach more than 95 % of the 28-day strength of unfrozen mortar. Interestingly, the sorptivity coefficient and total charge passed of early-frozen mortar are much higher than the level of unfrozen mortar, and the loss of resistance to water penetration and chloride ion penetration exceeds 20 %, indicating that early frost attack causes more severe damage to the durability than to the strength of mortar. Mercury intrusion porosimetry (MIP) results show that early frost attack can increase the pore volume of >50 nm and coarsen the pores within 10–50 nm. Correspondingly, key pore parameters (critical pore diameter, threshold pore diameter, and tortuosity) that affect the durability of mortar are also negatively affected. Energy dispersive spectroscopy (EDS) analysis also shows that after suffering early frost attack, the interfacial transition zone (ITZ) thickness of mortar is increased from 4 to 10 μm to 8–13 μm, and the probability of high Ca/Si ratios (4–10) in the ITZ is also increased. Finally, it is concluded that the coupling effect of pore structure coarsening and ITZ degradation leads to more severe durability loss.

Hybrid effects of graphene oxide-zeolitic imidazolate framework-67 (GO@ZIF-67) nanocomposite on mechanical, thermal, and microstructure properties of cement mortar

The addition of two-dimensional nanomaterials, such as graphene oxide (GO), and three-dimensional nanomaterials, such as zeolitic imidazolate framework-67 (ZIF-67), has shown great promise in improving the characteristics of cement-based systems. Consequently, a thorough understanding of the synergistic interactions between 2D and 3D nanomaterials in cement-based mortars is necessary. However, there is a lack of research on the use of graphene oxide-zeolitic imidazolate framework-67 (GO@ZIF-67) nanocomposites. Accordingly, this study investigated the hybrid effects of GO@ZIF-67 nanocomposites on the mechanical strength, hydration kinetics, shrinkage performance, and microstructural features of cement mortars. The GO@ZIF-67 nanocomposite was synthesized and added to the cement mortar at various concentrations (0.3, 0.4, and 0.5 wt %). The developed nanocomposite cement mortar was characterized using SEM-EDS, XRD, and DSC-TGA. The results indicated that the hybrid GO@ZIF-67 slightly improved the compressive strength of the cement paste, with a synergistic effect observed at specific concentrations. However, microstructural analysis revealed that the presence of hybrid nanomaterials did not facilitate the assembly and regulation of hydration crystal growth, nor did it significantly impede growth, resulting in minimal effects on the properties of cement mortar. Additionally, the nanocomposite influenced the hydration reactions and the formation of specific hydration products, introduced defects, and weakened the microstructure of the cement mortar. Moreover, an increase in the hybrid nanocomposite content led to higher drying shrinkage and water absorption, indicating a reduced durability of the cement mortar. Further research is required to optimize the use of GO@ZIF-67 nanocomposites in cement mortars to achieve the desired balance of properties.

Modelling of Restrained Shrinkage Stresses in Mortar using Artificial Neural Networks

Accurate prediction of tensile stresses in repair mortars is vital for the long-term durability of rehabilitated concrete structures. Existing analytical models are based on the material property theory and often struggle to capture the intricate and non-linear behavior exhibited by different mix types used in concrete. To address the limitation of existing models, neural networks were employed as a modelling approach for more robust and versatile predictions. The data used in developing the models was obtained from laboratory experiments. The input variables to the ANN model included: water content, cement, silica fume, superplasticizer, admixture, and age. Three distinct ANN-based models were developed based on: ordinary Portland cement, 10% silica fume as a partial replacement of cement and a combination of the two binder types. These models were evaluated using four performance metrics: coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). When mortars with ordinary Portland cement was used as a binder, the R2, MAE, MAPE, and RMSE were 99.74%, 0.0808, 0.0397, and 0.0138, respectively. For mortars with 10% silica fume, the ANN model predicted restrained shrinkage stresses in mortars with R2, MAE, MAPE, and RMSE values of 99.25%, 0.0090, 0.0731, and 0.3161, respectively. When both binders were used, the R2, MAE, MAPE, and RMSE were 99.77%, 0.0093, 0.0804, and 0.1775, respectively. The application of neural networks for predicting restrained shrinkage stresses in repair mortars outperforms conventional models with enhanced accuracy and reliability. The developed ANN models serve as powerful tools for assessing and optimizing the performance of repair mortars, enabling more efficient and precise design strategies in concrete repair.

Evaluation of the Performance of Fiber-Reinforced Mortars Based on Dredged Sludge

River-carried solids, especially during floods, lead to dam sedimentation. Dredging extends dam life, but excess unusable sediment storage threatens the environment. The aim of this work is to investigate the influence of the recovery of calcined mud from Chorfa dam on the physico-mechanical and chemical characteristics of mortars fiber bundles. The sludge is used as a partial substitute for cement by volume at rates of 10%, 15%, 20% and 25%. All test specimens had water / binder (W/B) ratio and steel fibers ratio. Testing programme included measuring the fluidity, ultrasonic pulse velocity test, dynamic modulus of elasticity, flexural and compressive strengths. Compared to the control mortar, the fluidity represented by the diameter of M0, M15 and M25 mixtures decreased by approximately 11%, 14% and 22%, respectively. The compressive strength of M15 increased by 17.4% at 28 days, compared with the control specimen. At 7 days, the ultrasonic speed of the M25 mixture decreases by 1.7% compared to that of M15. The dynamic modulus of elasticity of M20 and M25 increases by 13% and 12% as the age ranges from 2 to 28 days. At 28 days, the flexural strength of the M20 blends increased by approximately 64%.

The preparation and axial compressive properties of 3D-printed polymer lattice-reinforced cementitious composite columns

Research on the mechanical properties of 3D-printed lattice-reinforced cementitious materials is becoming increasingly widespread. The bending and compression performances of such materials have been studied from the perspectives of the lattice preparation materials, structural forms, gradient design, and cement-based material types. The extant research has primarily focused on the bending performance of lattice-reinforced specimens, while little research has been conducted on the compressive properties. In addition, the reinforcing effect of the lattice on cementitious materials under lateral constraints has not been considered. This article investigates the compressive performance of cement mortar reinforced by 3D-printed spiral lattices or skin structures with different volume reinforcement ratios (different grid constraint layers). Multi Jet Fusion (MJF) technology was used to print four types of spiral lattices, and six specimens, including a control group, were prepared. The experiment considered the performance differences of polymer-reinforced mortars with different volume reinforcement ratios, bonding performance, and skin reinforcement. The load, displacement, stress, strain and other data of the specimen were measured, and combined with the full field strain measured by DIC technology, the strength, energy absorption performance, ductility, elastic modulus, constraint effect, deformation mechanism, and failure mode of the specimen were comprehensively analyzed. The experimental results indicate that 3D-printed spiral or skin lattices can improve the ductility and energy absorption capacity of cementitious materials. However, the elastic modulus of the raw materials used to reinforce the structure is lower than that of cementitious materials, which will reduce the compressive strength and elastic modulus. In addition, the lateral deformation constraint effect of the lattice or skin structure on the cement mortar under axial compression is not significant. All cementitious specimens were found to exhibit the shear failure of the inclined section under axial compression. This article reveals that 3D printed spiral lattices can improve the deformation ability of cementitious composite materials under compression, providing new ideas for the ideal replacement of stirrups and the development of building energy conservation and emission reduction.

Optimizing self-sensing performance of conductive mortar via gradation of graphene coated aggregate

With the increasing focus on structural health monitoring of concrete during its service life, self-sensing functional concrete has emerged as an effective method for real-time detection and assessment of structural conditions. We recently proposed a new methodology of preparing conductive cementitious mortar with graphene-coated aggregates (Gr@Ag). Instead of the traditional approach, where conductive fillers are directly intermixed and uniformly distributed in the binding matrix, the development of Gr@Ag has created a more efficient path for electron transport through the connections of aggregates. The main objective of this study is to understand the effect of aggregate gradation on the electrical performances of conductive mortars, and the piezoresistivity is optimized by adjusting the aggregate packing. Electrochemical impedance spectroscopy was employed to investigate the underlying mechanisms of how aggregate gradation affects the mortar's electrical conductivity. It was found that both the internal resistance and resistivity of the conductive mortar considerably decreased with the reduction in Gr@Ag particle size. The contribution of conductive sand to the conductivity of mortar can reach 80.89–92.36 %, effectively transforming the conductive path from a disconnected state to a connected state. Reducing the particle size of the conductive aggregates contributes to an increase in particle contact rate, with the particle contact rate reaching up to 59 %. The presence of completely isolated conductive aggregates is noticeably reduced. As the particle size decreases, there is a significant reduction in mechanical performance. The conductive aggregates become relatively isolated from the matrix, and both the size of the conductive aggregates and the interfacial transition zone play vital roles to affect the mechanical properties.

Boosting mortar performance: use of recycled brick sand for enhanced mechanical properties

The construction industry is constantly seeking ways to become more sustainable. One area of exploration is mortar technology, where researchers are looking at replacing traditional components with alternative materials and adding a superplasticizer to improve mechanical strength and reduce the use of natural resources. The present study focuses on substituting brick waste sand in mortar at different replacement ratios of 0%, 10%, 30%, and 50%. The main objective is to investigate the effect of this substitution material on the properties of the mortar. The researchers have conducted compression and flexural tensile tests on prismatic specimens (4 x 4 x 16 cm³) at various curing periods (2, 7, and 28 days). The results showed that replacing 50% of sand with brick wastes significantly improved mortar properties. However, replacing more than 50% of the sand hurt the workability of the mortar. This study highlights the potential of using brick waste sand as an alternative to sand in mortar production, promoting resource conservation and sustainable construction. The findings suggest that while a 50% replacement ratio is beneficial, it is essential to carefully consider the mix design to maintain workability and overall performance.

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.