Types Of Mortars Research Articles

Cementitious mortars containing pozzolana under elevated temperatures

AbstractIn recent years, pozzolana are being increasingly used in different types of concretes and mortars. This investigation aims to evaluate the effect of replacing 7, 14, 21, and 28% cement (by weight) with silica fume (SF), granulated blast furnace slag (GBFS), zeolite, and fly ash (FA) under elevated temperatures. Forty mix designs were built with various water‐to‐cement ratios and plasticizers. Three hundred and six specimens were prepared, and the flexural, uniaxial compression and tensile tests were performed on specimens after exposure to elevated temperatures between 25°C and 900°C. The X‐ray diffraction (XRD) test was then performed on the two series of specimens. Accordingly, the results reveal that the average compressive strength of the control specimen and those containing SF, GBFS, Zeolite, and FA, respectively, is 23.17, 32.2, 34.87, 29.67, and 17.38 MPa. These values for the tensile and flexural strength tests are 0.77, 1.1, 1.02, 0.98, and 0.61 and 0.77, 1.23, 1.29, 0.93, and 0.87 MPa, respectively. Therefore, specimens containing zeolite and GBFS had better performance against heat. As per the increase in temperature, the size of the grains in the specimens containing the SF and GBFS in the XRD test shrunk less (about 6%) in contrast to those of the control specimen. The artificial neural networks (ANNs) were used to estimate the mechanical properties of the specimens at the age of 28 days.

Novel Shielding Mortars for Radiation Source Transportation and Storage

New types of mortar, M1 (60% sand, 25% cement, 10% ball clay, and 15% WO3), M2 (50% sand, 25% cement, 10% ball clay, and 25% WO3), M3 (60% sand, 25% cement, 10% Barite, and 15% WO3), and M4 (50% sand, 25% cement, 10% Barite, and 25% WO3), were prepared and the impact of WO3 and barite on their radiation shielding performance and mechanical properties was evaluated. The radiation attenuation factors were evaluated using five radioactive point sources, and a sodium iodide (NaI) scintillation detector (3″ × 3″) was used to detect the attenuation of gamma ray photons emitted from radioactive sources. The density values of the mortar samples lie within the range of 2.358 and 2.602 g/cm3. The compressive strength and the tensile strength of the prepared mortars increased with the increasing percentage of WO3. The M4 mortar had the highest linear attenuation coefficient (LAC) value. The LAC results demonstrated that adding barite and a high percentage of WO3 into the mortars notably enhanced the radiation shielding performance of the prepared mortar. The relationship between the half value layer (HVL) and the energy is direct, and so was used to calculate the thickness of mortar needed to absorb or scatter half the number of low-energy photons falling on the samples. At 0.06 MeV, the HVL values of the samples were 0.412, 0.280, 0.242, and 0.184 cm for samples M1–M4, respectively. The highest HVL values, obtained at 1.408 MeV, were 5.516, 5.202, 5.358, and 5.041 cm. Thus, a thinner layer of the M4 sample provided comparable attenuation of photons and radiation protection to the thicker M1–M3 samples. The new material is promising as an effective shield of radiation-emitting sources during transportation and long-term storage.

As argamassas históricas do castelo de Cifuentes (Guadalajara, Espanha)

This communication analyzes the results of the mineralogical and petrographic characterization of the rendering and masonry mortars from Cifuentes Castle. The castle has five towers, a 400 m2 courtyard and an Islamic influence main door. During the centuries several modifications have been done, reaching nowadays a state of almost abandonment. As part of a broader study of the materials and conservation state of the castle, this study allows us to differentiate several types of mortars that correlate with different construction periods of the monument: the core of the masonry of the courtyard wall made with gypsum mortar, and possibly with an Islamic origin; the main construction period of the castle, that used lime mortars with clay impurities and ceramic fragments; a reparations period with lime mortars that get thicker the core masonry of the courtyard; and a final rendering with lime and gypsum mortar finished with a layer of gray gypsum mortar.

Cement based-thermal energy storage mortar including blast furnace slag/capric acid shape-stabilized phase change material: Physical, mechanical, thermal properties and solar thermoregulation performance

Solar thermal energy efficiency of cementitious mortar is enhanced by introducing a phase change material (PCM) with thermal energy harvesting/releasing ability. Within this framework, a new type of cement based-thermal energy storage mortar (CBTESM) was developed by substituting blast furnace slag (BFS)/capric acid (CA) shape-stabilized PCM (SSPCM) with 15%, 30% and 45 wt% of sand. The results of XRD indicated that crystalline structure of CA was not affected with addition of BFS. The results of SEM/EDS confirmed successful impregnation of the melted CA into the BFS as carrying material thanks to the capillary forces. DSC analysis indicated that melting temperature and latent heat of fusion for SSPCM is 28.0˚C and 55.5 J/g while they are 28.52˚C and 13.8 J/g for CBTESM containing 45 wt% SSPCM. When 45 wt% SSPCM was added to mortar, bulk density (1.45 g/cm3), compressive strength (8.16 MPa) and thermal conductivity (0.601 W/m.K) decreased by 28.57%, 85.37% and 41.25%, respectively. The CBTESM sample including 15 wt% SSPCM additive (22.51 MPa) can meet the standard conditions in terms of compressive strength. Thermoregulation performance test under actual ambient conditions demonstrated that the developed CBTESM considerably reduced the indoor temperature. Theoretical calculations showed that a 13.5 kWh energy saving can be achieved by using 1 kg CBTESM in a wall having size of 3 × 4 × 0.2 m. Also 36.67, 35.73 and 5.87 kg-CO2 reduction in carbon emission would be reduced as per 1 kWh coal, natural gas and electricity consumptions, respectively.

Petrographical and geochemical criteria for a chronology of Roman mortars between the first century bce and the second century ce: The Curia of Pompey the Great

AbstractThirteen samples of mortar collected from different masonry structures of the Curia of Pompey the Great and from three mixtilinear basins located within the Sacred Area of Largo Argentina of Rome were studied. Despite the use of the same volcanic deposit, known as ‘Pozzolane Rosse’, to produce the fine aggregate in all these mortars, it was possible to highlight some distinctive features through the combination of geochemical analyses on selected trace elements and petrographic analysis under an optical microscope, allowing the three groups of mortars to be distinguished. These types of mortars reflect a perfect coincidence between the diversity of the volcanic materials used and the different construction phases identified and documented by the analysis of the stratigraphic units: a first construction phase of Pompeian age, a second phase of Augustan age and a final phase in the medieval period. Furthermore, it was possible to ascertain two phases of construction of the basins, the second coeval with the interventions of the Augustan period. Finally, this study increases knowledge about the methods of exploitation and selection of volcanic materials used to produce mortars in the Roman period, identifying additional elements useful to establish their origin and chronology of use.

Tensile behavior of basalt textile-reinforced mortar (BTRM)

This research aims to evaluate the tensile properties of basalt textile-reinforced mortar. The tension test was carried out on nineteen sets of pin action specimens. The variables studied in the current research are textile mesh size, number of plies, and mortar type, as well as coating some of the textiles with epoxy. The results indicated that increasing the number of plies resulted in an increase in the ductility and the ultimate load of specimens. The polymer modified cementitious mortar reinforced with glass fibers is the most efficient in enhancing the strength and ductility among the different types of mortars used in the study. Moreover, coating textiles with epoxy enhanced the ultimate load by about 25% compared to the uncoated specimens. The experimental results were compared with the corresponding values predicted by a model reported in the literature. The experimental results were in good agreement with those predicted using the model.

Synthesis and mechanical characterization of geopolymeric mortars derived from inorganic industrial waste from Peruvian informal mining

The geopolymeric mortars obtained by the chemical process of geopolymerization of waste from the Peruvian informal mining industry and subsequent addition of fine sand, were mechanically evaluated under ambient temperature and atmosphere conditions. The mechanical results found in the geopolymer mortars were compared with those found in conventional Portland cement mortars (control). The maximum uniaxial compressive stress values for the geopolymer mortars ranged from 7.5 to 27.1 MPa, with the best results when a binder:fine sand ratio of 1:2, molarity of the hardener solution of 20 M and a hardener solution:binder ratio of 0.6 was considered. The microstructure found for both types of mortars studied (control and geopolymeric) consisted of a continuous interconnected phase of binder (cement or geopolymerized inorganic mining residue) and a dispersed phase of small fine sand particles, located within the binder phase. The average real density and porosity of the geopolymeric materials studied were 2.71 g/cm3 and 27%, respectively.

Characterization of harvest residues ashes and ceramic waste powders originating from Vojvodina as potential supplementary cementitious materials

Traditionally, residential buildings in Vojvodina have masonry walls. Various types of mortar of mineral origin are most often used for joining masonry elements and finishing. The total amount of mortar for the construction of one building is not negligible. The estimated annual consumption of mortar in Vojvodina is about 198 thousand tons i.e. 27 thousand tons of cement and about 31.5 thousand tons of hydrated lime. It can easily be seen conventional mortars based on cement and lime are unacceptable in the light of environmental protection and sustainable development in the contemporary construction industry. Therefore, there is a need for research and development of new, alternative types of binders, based on locally available renewable and/or waste materials. The ceramic masonry elements and tiles industry generates ceramic waste during the production process. This waste, in powder form, could potentially be used as supplementary cementitious material (SCM). Biomass ash, generated by the combustion of harvest residues, as a renewable energy source, is another alternative to cement in modern building composites. This paper emphasizes the physical, chemical, and pozzolanic characteristics of the available agro-waste ashes and ceramic waste powder, originating from Vojvodina. The results indicate relatively high pozzolanicity of all tested ceramic powders and biomass ash based on cob corn, owing to their high fineness and reactive silica content. Furthermore, a catalogue of collected waste materials, illustrating basic data on the raw materials, processing method, landfilling, available quantities, and their tested properties is given.

Assessment of the Compressive Strength of Lime Mortars with Admixtures, Subjected to Two Curing Environments

This article presents the assessment of the compressive strength of three types of lime mortar, one without admixture and the remaining two added with metakaolin and brick dust. The chemical composition of the lime and the pozzolans was evaluated using the X-ray fluorescence (XRF) technique. The mortars were subjected to two curing conditions: humidity and temperature-controlled chamber, and accelerated carbonation chamber, then they were tested at ages of 7, 28, 60 and 90 days. The results showed that the samples cured in the carbonation chamber presented higher compressive strength values than the ones cured in the humidity and temperature-controlled chamber, due to the fact that lime mortars increase their strength with the carbonation of the calcium hydroxide that exists in the lime. Likewise, when adding metakaolin to the lime mortars cured in the humidity and temperature-controlled chamber, the values of compressive strength were close to those of the mortars with lime only, that were cured in the carbonation chamber. From the results of the research, it is notable that the use of pozzolans in lime mortars improves the short-term compressive strength, which is attractive for the rehabilitation of heritage buildings since in short periods of time it manages to match the strengths that lime mortars acquire over time.

Strength of the flexural joint of mortar joints and solid fired clay brick prisms

Masonry constructions built with mortar and solid fired clay bricks are subject to: high cement content, excessive water-cement ratio causing problems of mortar shrinkage during curing and differential movements between the brick and mortar caused by movements due to wind or seismic events. Earth movements generate some failures in simple masonry walls and confined masonry in solid brick joints, mainly with failure inclination angles varying from 45 degrees to 50 degrees. The objective of this research work was to estimate the flexural bond strength of the mortar joint and the solid fired clay brick and thus establish design parameters for non-structural masonry in the municipality of Ocanña, Colombia. From the fired clay brick manufacturers, 18 in total, simple random sampling was used to determine the sample size, 4 manufacturers were randomly selected. In addition, the characterization of the solid fired clay brick units was carried out with respect to their compressive strength, initial absorption rate and final absorption, as well as the mortar with respect to its compressive strength at 28 days, according to the Colombian standard for earthquake resistant constructions; for the determination of the flexural strength of the bonding mortar and solid brick units, a semiautomatic machine for flexural strength testing of masonry units, Pinzuar model PC-13, with a force measurement of 1000 N and an accuracy of 0.1 N, was designed. The flexural strength at the masonry joint was obtained for mortar type M with a value of 0.26 MPa, with a standard deviation of 0.01 MPa and a coefficient of variation of 4.72%. As for mortars type N and S, the average strength value was equal to 0.24 MPa for the two types of mortar, with standard deviation of 0.03 MPa and 0.01 MPa respectively, and coefficient of variation of 11.4% and 3.18% respectively. Given the importance of the variables, an interpretation of physical of the relationship between the properties was made: compressive strength of the solid fired clay brick and flexural strength at the masonry joint, since their average values were similar.

The Effect of Silica Sand Proportion in Laser Scabbling Process on Cement Mortar

Cement mortar composite has a wide range of applications on construction sites, including masonry, plastering and concrete repair. In construction sites, scabbling process is a method to remove from a few millimeters to several centimeters of defect concrete surfaces. As a result, it is essential to investigate the scabbling characteristics for cement mortar with different silica sand proportion in laser scabbling process. In this study, 5 types of cement mortar with different silica sand proportions in mixing were fabricated and scabbled by using a high-density power laser beam. The effects of silica sand proportion in color changing and penetration depth of the samples after laser scabbling process were studied. Furthermore, the generation of micro-cracks and pores were observed by using scanning electron microscopy (SEM). In addition, chemical composition changes between processed zone and non-processed zone were also evaluated by Energy Dispersive X-ray (EDX) analysis. The results of this study are expected to provide valuable knowledge in understanding of the laser scabbling process for cement-based materials.

Post-fire optimum mechanical properties of self-compacting mortar using Taguchi method and analysis of variance

In this research, to investigate the impact of high temperatures on the mechanical properties of this mortar type, first, nine mix designs consisting of different limestone powder percentages and water to cementitious material ratios were considered. To explore the impact of polypropylene and steel microfibers, instead of 54 mix designs, 18 designs were considered using the algorithm proposed by Taguchi, bringing the total number of mix designs to 27. Three levels were considered for the water to cementitious materials ratio, limestone powder content, and microfiber ratio. After the sample preparation, they were placed in a furnace and exposed to three temperature levels of 200, 400, and 600 °C at a heating rate of 2 °C/min. Mortar specimens to each target temperature were kept for 6 h. Finally, considering the results obtained after conducting tests on the specimens without microfibers cooled under ambient environment, the optimum water to cementitious materials ratio and limestone powder percentage were 0.4 and 30% for all the target temperatures in the compression test, 0.4 and 10% in the flexural test, respectively. After exposure to 200 and 400 °C, in the specimens containing polypropylene microfibers, optimum values observed for the water to cementitious materials ratio, limestone powder percentage, and microfiber ratio in the compression test reached 0.45, 30%, and 0.15%, respectively. Furthermore, in the flexural test, the corresponding values were 0.45, 10%, and 0.15%, respectively. The results obtained for 600 °C were different only for the optimum ratio of polypropylene microfibers, which was 0.05% for both compressive and flexural strengths. Moreover, in the specimens containing steel microfibers, for all the exposure temperatures, the optimum values of the water to cementitious materials ratio, limestone powder percentage, and microfiber ratio were 0.4, 30%, and 1.0% in the compressive strength test and 0.4, 10%, and 1.5%, in the flexural strength test, respectively. Also, the results obtained from the analysis of variance indicating the compression and flexural tests consequences are reliable.

Comparison of Influence of Superficial Strengthening with FRCM System and Kind of Mortar Type on Shear Strength of Autoclaved Aerated Concrete Masonry

This paper describes a comparison of results from testing shear strength of autoclaved aerated concrete (AAC) walls strengthened with superficial strengthening with the results of tests of walls made of various types of joints and mortar. The initial and characteristic shear strength and the angle of internal friction were compared. The test elements were made using two types of mortars, three types of joints, and two methods of reinforcement. The models were made using masonry units in the SOLBET OPTIMAL system. SOLBET 0.1 mortar, intended for thin joints, as well as SOLBET SMART polyurethane adhesive were used. Typical joints with a width equal to the thickness of the wall, shell bedded joints and joints without mortar were made. Models with typical joints were also tested as reinforced on one and two sides with the FRCM system, using the mineral cement matrix PBO-MX GOLD MASONRY and the PBO-MESH GOLD 22/22 mesh. A total of 56 models were tested in accordance with the requirements of PN-EN 1052-3: 2004. A significant influence of with superficial strengthening as well as the type of mortar and the construction of joints on the individual parameters of shear strength was demonstrated.

Influence of brick and concrete substrates on the performance of renders using in-situ testing techniques

The real performance of renders is influenced by several in-service factors. To analyze this influence two types of mortars - a traditional mortar (1:4 cement:sand in volume) and an industrial one-coat mortar - were applied on ceramic and concrete substrates, whose surface has been previously treated in three different ways: i) without moisture; ii) with double spraying of water, iii) with water immersion for 4 h. Through in-situ testing techniques (ultrasound, pendulum sclerometer and Karsten tube) at 28 and 90 days of age it was possible to discuss how the substrate and its suction influence the experimental results. When evaluating the performance over this period, it was possible to conclude that the applied mortars improved, in general, their mechanical behavior. In terms of preparation of the substrate, a double spray of water on the substrate surface achieved the best performance for both substrates. With the testing techniques it was found that the substrate and its suction had a significant influence on the performance of the applied mortars.

Fragility Curves for Material Characteristics and Damage Index for Brick Masonry Exposed to Freeze–Thaw Action

In regions exposed to floods followed by cold weather, brick masonry as a structural basis of the building envelope can be damaged due to the accompanying phenomenon of freezing and thawing. The main purpose of the article is the development of a mathematical model able to predict the chosen mechanical parameters and damage index of brick wallets for a given number of freeze-thaw cycles. For this, a statistical model derived from experimental data is used. As a result, regression curves for Young’s modulus and ductility for two types of mortar are obtained. Furthermore, fragility curves for ductility and also the damage index, which is based on displacement ductility, are presented. The obtained results enable probabilistic risk assessments in the case of deteriorated ductility and increased damage on brick masonry due to freeze–thaw cycles.

Mechanical properties and damage analysis of rubber cement mortar mixed with ceramic waste aggregate based on acoustic emission monitoring technology

Adding rubber particles into mortar or concrete has become one of the green ways to deal with waste rubber from the transportation industry. On this basis, this study proposes the addition of ceramic waste aggregate (CWA) to solve the issue of mortar strength reduction after the addition of rubber. This paper mainly analyses the mechanical properties of rubber cement mortar (RCM) mixed with different contents of CWA and the damage analysis of composite mortar in the three-point bending test by using acoustic emission (AE) monitoring technology. The flexural test and compressive test show that the mechanical properties of composite mortar can be greatly improved by adding CWA into the mortar. With increasing CWA content, the strength first increases at low content and then decreases at high content due to the high water absorption of the aggregate. At the same time, combined with AE technology, the cumulative energy, cumulative number of hits, Ib-value analysis, intensity analysis and RA-AF value analysis of different kinds of composite mortar are analysed and compared. Based on the AE source location and damage index, the fracture damage characteristics of three kinds of mortar in the three-point bending test are described. The frequency analysis of the AE signal is carried out by the wavelet packet transform (WPT), and the energy percentage change of the AE signal within a specific frequency interval is analysed. Based on the above AE analysis method, the three kinds of mortar have different AE signals, corresponding to different fracture characteristics. This paper provides the basis of mechanical and AE tests for a new type of green composite mortar.

Desarrollo de morteros de bajo impacto ambiental a partir de residuos sílico-aluminosos activados alcalinamente del sector minero

Due to the environmental problems related to the generation of mine tailings, the circular economy is presented as a solution, using mine tailings as a raw material for the manufacture of construction materials. In this paper, mortars from alkaline-activated mining waste were generated. Coal mining residues (sandy-RC and clayey-RCd) and gold vein mining (flotation tails-CF) were studied, and they were activated by a mixture of NaOH and Na2SiO3 solution. Two types of mortars were analyzed to assess influence of particle size were manufactured, the first by using original granulometry tailing and the second with milled residue. In addition, for the milled residues, partial substitutions for Portland cement were used, and each type of mortar was set at 24 and 80°C. Crystalline phases in mortars were identified by X-ray diffraction (XRD), and the morphology of the fracture surfaces after the compression test was analyzed with scanning electron microscopy (SEM). The results show that the compressive strength of the specimens produced from milled residue was higher value in comparison with original granulometry specimens. In addition, setting temperature used does not represent the influence on the property evaluated. The best condition found presented a compressive strength of 17.7MPa for 24°C and 17.8MPa for 80°C, with reduction percentages of emissions and embodied energy of 32.85% and 22.73% respectively.

The experimental study on damaged square columns strengthened by reinforcement mesh steel fiber

Eight common reinforced concrete columns were damaged by different sizes loads. The damaged reinforced concrete columns were strengthened by reinforcement mesh steel fiber. Three identical test pieces were made to explore the dispersion of the reinforcement method. The axial compression experiment was researched by factor of mortar types, damage degree, the lateral and longitudinal spacing. The formula of the axial bearing capacity of damaged square columns were strengthened by reinforcement mesh steel fiber was proposed. The calculated values agreed well with the experimental results. The test results showed that the damaged square columns were strengthened by reinforcement mesh steel fiber was an effective reinforcement method. This method was less discrete and can not only improve the ultimate bearing capacity, cracking load ductility and anti-cracking ability, but also the mechanical properties and failure mode can be effectively improved.

An experimental length scale investigation on viscoelastic behavior of bituminous composites: Focusing on mortar scale

The mortar component plays an essential role in forming different asphalt mixture distresses. The fine aggregate size affects the viscoelastic behavior of mortar. In this study, three cutting sizes of 3.35, 2.36, and 1.7 mm, on the aggregate grading curve were considered to construct the mortar scales, namely mortar (I), (II), and (III), respectively. With a unique loading mode, a frequency sweep test was performed on four different length scales, including bitumen, asphalt mastic, mortar, and asphalt mixture, to make a direct comparison through a multi-scale approach. Also, a stress sweep test was conducted to find the mortar scale's linear viscoelastic domain. The results indicate that different mortar types have variable linear viscoelastic domains. The master curves of dynamic modulus (E*) and phase angle (δ) show that adding filler to bitumen has more effect on the E* than the δ. Although scaling up from the mastic to mortar (II) causes a significant difference between the viscoelastic parameters, the results remained approximately the same. The main gap between the mixture and mentioned sub-scales is filled with mortar (I). While the Cole-Cole diagrams demonstrate that the bitumen to mortar (II) scales have the same behavior, the closest scale to the mixture is the mortar (I). Therefore, using a cutting size of 3.35 mm is recommended to fabricate mortar (for asphalt mixture with a nominal maximum aggregate size of 19 mm) instead of 2.36 mm, which was suggested in previous studies.

Property comparison of steel slag cement mortar with hydroxyethyl methyl cellulose having different degrees of substitution and PAAm modification

The aim of this study is to explore the influence of HEMC with different total substitution degrees and polyacrylamide (PAAm) modification on the properties of steel slag cement mortar. The results show that HEMC increases the water retention rate, consistency, tensile bond strength, and flexibility of all types of steel slag cement mortars. The addition of HEMC, however, leads to a decrease in compressive strength and flexural strength. The total substitution degree or PAAm modification of HEMC has a minor effect on the water retention rate, compressive strength, flexibility, and pore size distribution of steel slag cement mortar. HEMC with a higher total substitution degree is more beneficial to the development of tensile bond strength except for SL1 cement mortar at an early age (3 days and 7 days), whereas PAAm weakens the positive effect of HEMC on the tensile bond strength. Mercury intrusion porosimeter (MIP) tests show that the addition of HEMC increases the porosity of steel slag cement mortar.