Properties Of Mortar Research Articles

Hydration, fresh, mechanical, and freeze-thaw properties of cement mortar incorporated with polymeric microspheres

Hydration, fresh, mechanical, and freeze-thaw properties of cement mortar incorporated with polymeric microspheres

Effect of calcium stearate on cellulose acetate-based mortars

The purpose of this study is to investigate the properties of cellulose acetate-based mortars with the addition of calcium stearate (CS), superplasticizer (SP) and metakaolin (MK). Previous research has shown that cellulose acetate (CA) fibers from industrial cigarette butts (CB) treatment can be incorporated into standard mortars at a rate of 1.3 wt%. CS was added in various proportions by weight (0.5, 1, 1.5 wt%), and their influence on cement hydration and microstructure was studied using various investigative techniques. The addition of CS was found to be beneficial in reducing the amount of water absorbed by CA, despite the significant absorption of these fibers. Furthermore, a CS rate of 1 wt% decreased CA-based mortar shrinkage. Additionally, 1 wt% CS improved by 18% the compressive strength of CA-based mortars manufactured with SP compared to the reference CA-mortar. CA fibers and CS seem to modify mortar microstructure by creating a plurimodal pore size distribution and reducing capillary pores. The CS addition, however, resulted in more cracks and reduced workability due to the weakening of the bond between the cement paste components. MK-mortars showed a slight 15% reduction in compressive strength and 13% reduction in bending strength; along with a 20% increase in shrinkage. By incorporating CA fibers as an additive along with CS or MK, CA-based mortars can improve some properties, including shrinkage and mechanical strength. Further, this approach offers a potential solution to CB pollution by reducing the environmental impact of this waste.

Feasibility study of replacing part of cement by igneous rock powder as cementitious material: based on mortar macroscopic properties and microstructure

To address the increasing demand for cement and promote sustainable development, the utilization of igneous rock powder as a supplementary material to partially replace cement has emerged as an effective strategy. In this study, the fluidity and mechanical properties of the igneous rock powder-cement (IRP-OPC) composite system were investigated, and the hydration product and microstructure of IRP-OPC were analyzed by using TG/DSC, N2 adsorption-desorption curve (BET) and SEM. The experimental findings demonstrate that the performance of the andesite powder-cement composite cementing system (AP-OPC) surpasses that of tuff powder-cement slurry (TP-OPC) and granite powder-cement slurry (GP-OPC). When the dosage of andesite powder (AP) is 5%–15%, the flowability, flexural strength and compressive strength of cement mortar are improved. When the dosage is 10%, the 28-day compressive strength is 48.3 MPa. Under the condition of low content (10%), part of Ca(OH)2 is fully consumed by active SiO2 in AP and reacts to form C-S-H. Hydration products and AP particles with small particle size are filled into the structural gap, which refines the pore structure of cement slurry, and the increase in compactness provides support for the development of strength in the later stage. The use of 5%–15% AP instead of OPC can improve fluidity and meet the strength requirements of P.O 42.5 Portland cement. This substitution not only reduces engineering costs but also enhances resource utilization.

The Use of Ground Coal Bottom Ash/Slag as a Cement Replacement for Sustainable Concrete Infrastructure.

Cement production requires considerable energy and natural resources, severely impacting the environment due to harmful gas emissions. Coal bottom ash (CBA) and coal boiler slag (CBS), byproducts of coal-fired powerplants having pozzolanic properties, can be mechanically ground and replace cement in concrete, which reduces waste in landfills, preserves natural resources, and reduces health hazards. This study was performed to determine the optimum cement replacement amount of ground CBA (GCBA) and ground CBS (GCBS) in concrete, which was 10% for GCBA and 5% for GCBS. GCBA-based concrete exhibited superior tensile strength, modulus of elasticity, and durability compared to the control. In the Rapid Chloride Penetration Test, 10% GCBA concrete resulted in 2026 coulombs at 56 days, compared to 3405 coulombs for the control, indicating more resistance to chloride penetration. Incorporating 2.5% nanoclay in GCBA-based concrete increased the optimum GCBA content by 5%, and the compressive strength of 15% GCBA concrete increased by 4 MPa. The mortar consisting of the finest GCBA(L1) having Blaine fineness of 3072 g/cm2 yielded the highest compressive strength (32.7 MPa). The study discovered that the compressive strength of GCBA and GCBS-based mortars increases with fineness, and meeting the recommended fineness limit in ASTM C618 enhances concrete or mortar properties.

Synergistic effect of carbon nanotubes and polyvinyl alcohol on the mechanical performance and microstructure of cement mortar

Abstract Herein, carbon nanotubes (CNTs) and polyvinyl alcohol (PVA) were used as hybrid modifiers to enhance the mechanical properties of cement mortar and overcome the limitations of modification methods based on only polymers and nanomaterials. The use of PVA latex as a bridging agent with the aid of ultrasound energy effectively improved the dispersion uniformity and stability of CNTs. The results indicate that doping an appropriate amount of PVA in CNT-modified cement mortar, especially those modified with hydroxylated CNTs (h-CNTs), could synergistically improve performance. Amongst the samples, the h-CNT-modified cement mortar incorporated with 1 wt% PVA showed the optimal mechanical properties. The compressive and flexural strengths of this cement mortar increased by 33 and 42%, respectively, compared with those of cement mortars modified with h-CNTs alone. The microscopic characterisation results showed that the formation of a uniformly distributed h-CNT/PVA film network in the matrix effective filling of pores and bridging of cracks were responsible for performance enhancement.

Effect of dry-wet cycling on NOx degradation and sterilization properties of cement mortar with g-C3N4/CoAl-LDH

The influencing mechanism of dry-wet cycling on the NOx degradation and sterilization properties of photocatalytic cement mortar (PCM) with g-C3N4/CoAl-LDH was investigated through the optical properties, mineral composition of cement hydration products, pore characteristics and nitrogen (N) content. The results indicate that as the cycle number increases, the N content, band gap, Urbach energy, NOx degradation rate and sterilization rate exhibit periodic variations, while the peak intensity of CH (a cement hydration product) decreases gradually. After 10 cycles, PCM demonstrates the maximum Urbach energy, N content, NOx degradation and sterilization rate, as well as the minimum band gap. At this stage, the Urbach energy, N content, NOx degradation and sterilization rate of PCM with 1.0 % g-C3N4/CoAl-LDH increase by 16.2 %, 24.9 %, 15.4 % and 40.8 %, while the band gap and the CH peak intensity decrease by 5.4 % and 23.4 %, respectively. Although the NOx degradation and sterilization rates of PCM exhibit periodic fluctuations during the dry-wet cycling, both of them surpass those before the cycles, which shows the excellent photocatalytic durability of PCM. It is expected that this study not only presents a new perspective on evaluating the durability of PCM’s photocatalytic property, but also provides an alternative approach for the design of new multifunctional nanocomposites in cementitious materials for environmental pollution control.

Influence of geometric shape, pore structure and surface modification of recycled fine aggregate on the rheology behaviour and strength development of mortar

The complex physical properties of recycled fine aggregate affect the rheological and mechanical properties of mortar, thereby limiting its application in cement-based materials. This paper evaluated the geometric shape and pore structure of natural fine aggregate (NFA), recycled fine aggregate (RFA), and recycled fine aggregate modified by water glass (MRFA), and studied its water absorption and bulk density. The influence of complex physical properties of RFA before and after modification on the rheological behavior, strength development, and microscopic properties of mortar was analyzed. The rheological tests were carried out on the fresh mortar with 7 mixes, and the compressive strength and flexural strength of hardened mortar after curing for 3, 7 and 28 days were tested. The results shown that the modification of water glass has improved the water absorption and geometric shape of RFA to some extent, resulting in a small increase in the apparent viscosity and yield stress of recycled mortar compared to NFA mortar. When the replacement level of RFA was less than 30 %, the compressive strength of recycled mortar was 13 % higher than that of NFA mortar. As the replacement level increased to 40 %, the incorporation of water glass also helped to improve the mortar strength. The irregular geometric shape and high water absorption of RFA were conducive to achieving dense mechanical bonding and reducing the Ca/Si ratio in the interface transition zone.

Abrasion Resistance and Microstructural Properties of Sustainable Geopolymer Mortar Produced with Hybrid Blends of GGBFS and Various Earth Materials

Abrasion Resistance and Microstructural Properties of Sustainable Geopolymer Mortar Produced with Hybrid Blends of GGBFS and Various Earth Materials

Study on the influencing factors of mechanical properties of anti-icing modified asphalt mortar

Accumulated snow and ice on road surface affect traffic operation. Anti-icing asphalt pavement is widely implemented as an active snow melting technology. However, there are few studies on anti-icing modified asphalt mortar mechanical properties and the effect of mortar materials on the interaction between modified asphalt and anti-icing filler. For this reason, this study investigated the mechanical properties of asphalt including rheological, high-temperature, fatigue and low-temperature properties through frequency and temperature scan, multiple stress creep recovery, linear amplitude scan, and single edge notched beam test. Based on this, the significant factors affecting asphalt mechanical properties were identified by analysis of variance. Subsequently, the Palierne-C-G* parameter was used to quantify the interaction between modified asphalt and anti-icing filler, and the effect of asphalt chemical structure on the interaction was revealed by Fourier Transform Infrared Spectroscopy (FTIR) test. The results indicated that the anti-icing filler significantly improved the high temperature and fatigue resistance of asphalt. Compared with SBS modified asphalt mortar, the mechanical properties of composite modified asphalt mortar were superior. The most significant factor affecting the mechanical properties of SBS modified asphalt mortar was modifier dosage, while the most significant factor affecting the composite modified asphalt mortar was crushed rubber dosage. The interaction showed a decreasing trend with the increase of frequency, while it appeared to increase and then decrease with the increase of temperature. The carbonyl functional group of asphalt correlated best with the interaction between asphalt and filler.

Comparative Study between Multiwall Carbon Nano Tube and Carbon Waste from Aluminium Production in the Preparation of Thermally Stable Cementitious Mortar

Objective: The objective of this study is to conduct a comparative investigation into the performance of multiwall carbon nanotube (MWCNT) and carbon wastes (C-waste) derived from the aluminum industry in the creation of thermally stable cementitious mortar. Specifically, the research aims to assess their impact on compressive strength and thermal stability, with a focus on identifying the superior additive for enhancing the properties of cement mortar. Methods: Cement mortar is produced using a blend of CEMIII cement and sand passing through a 1 mm sieve. Various ratios of MWCNT and C-waste, ranging from 0.1% to 0.7%, are incorporated into the mixture. Compressive strength tests are conducted at different intervals, up to 90 days, to evaluate the effects of additives on strength enhancement. Additionally, the resistance to high temperatures is examined by subjecting the mortar samples to firing temperatures up to 700 degrees Celsius. Results: The inclusion of both MWCNT and C-waste leads to improvements in compressive strength values, with the most significant enhancement observed at 0.1% concentration, resulting in approximately 70MPa and 75MPa at 90 days, respectively. Notably, C-waste demonstrates superior physical and mechanical properties compared to MWCNT, along with a lower production cost. Moreover, both additives exceed the specified limits for thermal resistance in mortar, achieving measurements of about 60MPa for MWCNT and 63MPa for C-waste when exposed to firing temperatures of 700 degrees Celsius. These results highlight the higher thermal stability of C-waste relative to MWCNT. Conclusion: In conclusion, this study confirms the efficacy of utilizing C-waste as an additive in cementitious mortar production, showcasing its superior performance over MWCNT in terms of compressive strength enhancement and thermal stability. The findings underscore the potential of repurposing industrial by-products such as C-waste to improve material properties while also addressing environmental concerns and reducing production costs in construction applications.

Effect of Mineral Admixtures on Physical, Mechanical, and Microstructural Properties of Flue Gas Desulfurization Gypsum-Based Self-Leveling Mortar.

The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), retarder, and defoamer were used to prepare GSLM. The impact of mineral admixtures (steel slag (SS), silica fume (SF), and fly ash (FA)) on the physical, mechanical, and microstructural properties of GSLM was examined through hydration heat, X-ray diffractometry (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) analyses. The GSLM benchmark mix ratio was determined as follows: 94% of desulfurization building gypsum, 6% of cement, 0.638% each of water reducer and retarder, 0.085% each of HPMC and defoamer (calculated additive ratio relative to gypsum), and 0.54 water-to-cement ratio. Although the initial fluidity decreased in the GSLM slurry with silica fume, there was minimal change in 30 min fluidity. Notably, at an SS content of 16%, the GSLM exhibited optimal flexural strength (6.6 MPa) and compressive strength (20.4 MPa). Hydration heat, XRD, and Raman analyses revealed that a small portion of SS actively participated in the hydration reaction, while the remaining SS served as a filler.

Building a Greener Future: Advancing Concrete Production Sustainability and the Thermal Properties of 3D-Printed Mortars

The integration of waste materials in extrudable cement mixtures has the potential to make the construction industry more sustainable by reducing carbon footprints and developing eco-friendly materials. This along with advancements in 3D concrete printing (3DCP) provides engineering and architectural benefits by reducing material waste and costs. In this paper, the impact of waste incorporation on properties of mortar and concrete is examined. The use of waste materials, such as pumice, coal slag, agricultural lignocellulosic residues, and recycled rubber tyres, to improve thermal insulation and durability of cementitious composites is discussed. In addition, the incorporation of air-entraining admixtures with surfactant activity is explored for their indirect effect on thermal behaviour, pore size reduction, and enhancement in concrete properties. This review includes important topics such as a strength resistance to freezing and thawing, fire resistance, plasticising effect, and delay in cement hydration. These findings highlight the benefits of using diverse waste materials in construction, providing a multidimensional approach to waste management, cost optimization, and enhanced construction materials in the context of 3DCP.

Polymer-modified mortar flexibility of the masonry-concrete structure interface

High crack occurrences at the masonry-infilled wall partition-reinforced concrete structure interface is a problem that challenges the Brazilian construction process. Improving the mortar’s flexibility is suggested as a potential solution, but it's still not widely known. This paper evaluates industrialized mortar properties modified with four polymers and one plasticizer additive. The research methodology consisted of an experimental investigation related to the mortar properties using styrene-acrylic copolymer (SAE), polyvinyl acetate copolymer (PVAc), styrene-butadiene copolymer (SBR), white glue PVA (polyvinyl acetate), and a sulfated ethoxylated fatty alcohol salt plasticizer additive. The polymers were used in addition to (4%, 5% and 8%) and instead of (4% and 5%) the amount of water established by the manufacturer of the reference mortar, while the amount of additive used was 0.08%. The investigation characterization considered the fresh and hardened conditions, especially, the flexibility evaluation, and tests of elasticity modulus and transverse deformation were carried out, in addition to scanning electron microscopy (SEM). The results showed that there was an elasticity modulus reduction of all mixtures compared with the reference mortar without modification. The transverse deformation results range from a minimum of 0.23 mm (SBR) to a maximum of 0.94 mm (SAE). Regarding SEM, the tests with polymers have smoother and less porous surfaces. The mortar flexibility performance with different additive contents is the main contribution of this research.

Exploring Olive Pit Powder as a Filler for Enhanced Thermal Insulation in Epoxy Mortars to Increase Sustainability in Building Construction

This article explores the use of olive pit powder (OPP) as a promising resource for enhancing the thermal insulation properties of epoxy mortars. A comprehensive analysis of the chemical and physical characteristics of OPP was conducted, employing analytical techniques including scanning electron microscopy (SEM), thermogravimetric analysis and emitted gas analysis (TG-MS-EGA), and proximal analysis. Experimental samples of epoxy grout were prepared by using different proportions of a conventional inorganic filler, quartz powder, and OPP within an epoxy mortar matrix. As the percentage of OPP in the formulation increased, the microstructure of the samples gradually became more porous and less compact. Consequently, there was a decrease in density with the increase in OPP content. The 28-day compressive strength decreased from 46 MPa to 12.8 MPa, respectively, in the samples containing only quartz (Sample E) and only OPP (Sample A) as a filler. Similarly, flexural strength decreased from 35.2 to 5.3 MPa. The thermal conductivity decreased from 0.3 W/mK in Sample E to 0.11 in Sample A. Therefore, increasing the %wt of OPP improved insulating properties while reducing the mechanical resistance values. This study highlights the potential of OPP as an environmentally friendly and thermally efficient filler for epoxy mortars, thereby promoting sustainable construction practices.

Mechanical and fracture properties of mortars reinforced with glass fibre and prepared with different cement types

PurposeThe main aim of the current study is to investigate the effect of Anti-Crack HP 67/36 glass fibre on the mechanical performance of mortars made of cement, with a focus on post-cracking evaluations using the digital image correlation (DIC) technique.Design/methodology/approachExperimental tests were carried out on 36-mm long fibres at 0.8% by volume and added to the normal strength (NSM), high strength (HSM) and high strength mortar with fly ash (HSMFA) mortars. CEM I 52.5 CP2 NF, CEM II/A-L 42.5 NF and CEM III/C 32.5 N-SR PM were used for each series of mortar to assess the performance of the glass fibres with the types of cement. F-class fly (FA) ash was used to reduce global CO2 emissions.FindingsThe mortar’s strength decreased as the cement types changed from CEM I to CEM II and III. However, due to changes in the portlandite content of the cement, water porosity increased for both types of mortar, without and with fibre. It was also found that using glass fibre increased flexural strength more than compressive strength, regardless of the type of cement used. For all the strength classes, it was found that the mortar mixes with CEM I had the highest critical crack opening (wc) and fracture energy (GF), followed by CEM II and III. No significant effects were observed in the mortar’s property by replacing fly ash (12%).Research limitations/implicationsOnly mortars were formulated in this study, but the results must be verified at the concrete scale.Practical implicationsValidation of the DIC technique to characterize the post-cracking behaviour of cement-based material. Use of glass fibres to improve the material’s resistance to cracking.Social implicationsUse of CEM II and CEM III cements with low CO2 footprint instead of CEMI without altering the mechanical performance of the material.Originality/valueThe work is a further contribution to studying the cracking behaviour of several series of variable mortars depending on the resistance class and the type of cement used.

Influence of bacterial biomineralization conditions on the microstructural characteristics of cement mortar

Bacterial concrete is considered an effective self-healing material due to its capacity to repair damages such as cracks autonomously throughout microbially induced calcium carbonate precipitation (MICP). This study aimed to evaluate the direct incorporation of bacteria into mortar within the framework of concrete damage repairing technol-ogy. Sporosarcina pasteurii, a bacterium capable of surviving in alkaline conditions and inducing biomineralization by precipitating calcium carbonate, was selected for this purpose. Cement mortars with and without bacteria were prepared, and these samples were cured in different solutions to examine bacterial reactivity: a media solution for bacterial growth and calcium carbonate precipitation, a urea solution for calcium carbonate precipitation, and normal water. Mechanical properties and microstructural characteristics were investigated using various approaches. The out-comes revealed that the calcium carbonate precipitated by bacteria in cement mortar exhibited varying phases, such as calcite and vaterite, depending on the specific curing solutions employed. Particularly, the presence of properly precipitated calcium carbonate was found to significantly enhance the durability and mechanical properties of the cement mortar.

Engineering properties of seawater-mixed mortar with batching plant residual waste as aggregate replacement

Engineering properties of seawater-mixed mortar with batching plant residual waste as aggregate replacement

Influence of corn cob ash additive on the structure and properties of cement concrete

In accordance with the Sustainable Development Goals (SDGs) concept, there is a need to find technologies that would help make concrete production less energy intensive and more environmentally friendly. One technology involves substituting some mineral components in concrete with rapidly renewable plant-based alternatives. This study aims to establish the essential patterns among the concrete composition, micro-structure, and properties of cementitious composites modified with corn waste. Additionally, it seeks to explore the potential for producing high-quality composites using this waste material. To assess the effectiveness of this kind of waste, the strength of the cement-sand mortar, several characteristics like compressive strength, flexural durability and water absorption of hardened concrete were studied. It is established that introducing corn cob ash (CCA) to substitute a part of the cement up to 16% is justified and allows to obtain mortar and concrete with enhanced properties. CCA has a beneficial impact on the properties of Cement Sand Mortar (CSM) when replacing cement by no more than 15%. The maximum effect was achieved at 10% CCA, and the rise of compressive and flexural strength were 6.06% and 6.32%. In concrete with a CCA amount of 8%, the most impressive growth of compressive strength was 7.14%, and the lowest value of water absorption, which is 10.31% lower compared to the ordinary composition. Including CCA reduces the properties like workability, density of concrete mixtures, and the hardened composite density. The scientific results obtained prove the possibility of using CCA as an effective mineral pozzolanic additive that improves the properties of concrete.

Self-healing properties of mortar with crystalline admixture: experimental investigation and parameter optimization

The inclusion of crystalline admixture (CA) is a highly effective method for enhancing the self-healing properties of mortar. This study examined the complexing abilities of different complexing agents under varying temperatures, pH levels, and ion species in order to select effective complexing agents for diverse environments, as complexing agents play a crucial role in CAs. After determining the type of complexing agent, an orthogonal array design was used to optimize the components of CA, and the strengthening mechanism of CA for mortar was discussed through microstructure analysis. The results showed that the complexation behavior of triethanolamine (TEA) and glycine performed better than sodium citrate for different pH levels, temperatures, and ion species. Meanwhile, TEA and glycine showed complementarity at different stages, so TEA and glycine were used as complexing agents in this study. Based on the orthogonal experiment, the optimal contents of Na2SiO3, Na2CO3, TEA, glycine, Ca(COOH)2, and nano-SiO2 in CA were determined to be 1.0%, 1.0%, 0.04%, 1.0%, 0.5%, and 1.0%, respectively. Under the synergistic effect of TEA and glycine, the hydration of aluminate and ferrialuminate was accelerated, and the hydration degree of cement paste was increased. At 28 d, the contents of CaCO3, calcium-silicate-hydrate (C-S-H) gel, and ettringite of cement paste with CA were higher than these of plain paste, but its Ca(OH)2 content was lower. Although the Ca(OH)2 content in the cement paste with CA was lower, the Ca(OH)2 crystal structure filled in the pores was larger. Therefore, the mortar mixed with CA exhibited higher compressive strength, water impermeability, and self-healing ability.

Effect of titanium dioxide on fresh and mechanical properties of Mortar: A review

Nanotechnology-based engineering approaches are rapidly developing throughout the world. Modern, cutting-edge nanotechnology has proven useful in a variety of technical applications. In emerging and developed countries, increasing infrastructure needs a considerable amount of cement, which has a significantly impact on the environment and human health, resulting in greenhouse gas emissions and severe acute respiratory illnesses (asthma and silicosis, respectively). To overcome such difficulties, cement consumption in building materials must be reduced. Several novel extra materials have lately been introduced to improve the performance of mortar. Nano-titanium dioxide (NT) in cement mortar is widely used in green building construction because NT capable to the degradation of air pollution, self-cleaning, and enhancing mechanical, microstructural, and durability properties. In this paper, the effect of NT on fresh and hardened properties of cement mortar has been discussed. For the collection, screening and implementation of data for review paper PRISMA analysis and VOSviewer technique was used. Existing literature indicates that the reduction in workability 15% − 20% whereas improvement in compressive strength (CS) up to 15% and tensile strength up to 45% was noted with NT in mortar. Current research supports using NT as a cement replacement in mortar. Aside from the key findings, some identified gaps, problems, and future scope challenges have been presented in order to develop NT based mortar as a sustainable material in the building sector.