Types Of Mortars Research Articles

A multi-analytical approach for pore structure assessment in historic lime mortars

Porosity of a mortar significantly influences its mechanical characteristics as well as durability. To ensure compatibility while designing a repair mortar for historic masonry, it is important to have both a qualitative and quantitative description of the pore structure. In this paper, we present the porosity investigations of two types of historic lime mortars by scanning electron microscopy (SEM), X-ray tomography (XRT), water sorptivity and mercury intrusion porosimetry (MIP). The overflow method is used to quantify the porosity from the frames/slices obtained from the SEM/XRT respectively. Different techniques measure different aspects of the pore structure and a comparison of results from different analytical methods allowed overcoming their specific limitations and achieving a better knowledge of the pore system of historic mortars.

Influence of surface reinforcement on the strength of brick masonry wall

In this article, an attempt is made to evaluate the load carrying capacity of one brick thick vertical, surface reinforced masonry wall and compared with unreinforced wall. Locally available bricks of compressive strength of 4–8 MPa is used in study. Basic properties of bricks and three types of mortars are evaluated. Compressive strength, shear bond and flexural bond strength of English bonded prisms is also explored. Experimental results indicated bond strength of English bonded prisms built with cement sand mortar and cement soil mortar was comparable. Use of lime showed reduced bond strength and compressive strength. Use of vertical reinforcement in masonry construction is mainly devoted for resisting lateral forces. Compressive strength of 0.1% externally reinforced masonry wall was 7.4% more when compared to unreinforced masonry. Similarly, modulus of elasticity of reinforced masonry wall is 2.08 times of unreinforced masonry wall.

Towards an enhanced fatigue evaluation of bituminous mortars

The fatigue resistance, as a performance indicator, is of paramount importance for the selection and benchmarking of bituminous materials. The bituminous mortar can be considered as the medium that connects and envelopes the coarse aggregate skeleton, and hence will significantly influence the fatigue resistance at bulk-scale. Therefore this study presents the steps and challenges of a new testing framework to evaluate the fatigue resistance of bituminous mortars. To do so, first, a new test geometry is introduced, which will ensure cohesive failure in a predefined area. The integrity of this sample geometry is assessed theoretically through finite element simulations and by computer tomography scans. Secondly, specimens of the new geometry are evaluated experimentally using a dynamic shear rheometer, where time-sweep tests are performed on two control mortar types under various test conditions. The control mortar types are fabricated using two commercial bituminous binders, one modified and one neat binder, to evaluate the effect of binder type. The test results are comprehensively analysed using fundamental dissipated energy-based concepts but also empirical and phenomenological failure criteria, providing insights into the failure evolution. For the tested mortar types, the analysis shows good convergence with the considered fatigue models. Finally, using dissipated energy concepts led to the most consisted fatigue model, which is independent of binder type and test conditions.

Factors determining the quality of masonry – differentiation of resistance and reliability

A house or any other building without walls is truly hard to imagine. The first thing usually associated with walls is, of course, masonry. Today, masonry walls perform a load-bearing function in buildings up to four above-ground floors, in the higher parts of the buildings they perform a protective and stiffening function. However, there is a widespread opinion that the designer does not have to check the bearing capacity of masonry structures because masonry are were stand, are standing and will stand. Not everyone, however, currently works the wall as it should. The problem is that a lot of emphasis is now placed on reducing construction times. Therefore, there are a number of factors affecting the quality of the masonry structure, which overall reduce their safety. The article presents the influence of the quality of masonry on the differentiation of bearing capacity and reliability of an example masonry structure. The analyses included various values γm of the partial factor, recommended in the national annex PN-EN 1996-1, depending on the category of masonry units, class execution of works and type of mortar. In addition, a decrease in load capacity and reliability caused by the increase of the initial eccentric resulting from the inaccuracy of the masonry wall was examined.

Implications of new mineral phases in the isotopic composition of Roman lime mortars at the Kom el-Dikka archaeological site in Egypt

Over time, the carbonated components of lime-based mortars dissolve and recrystallise, inducing calcite cementation in the resulting micro- cracks and pores, favouring self-healing capacity. In such types of mortars, the binder may originally contain gypsum, or, on the other hand, dissolution and precipitation processes of compounds from different sources (soil, construction materials or airborne particles) may derive in the formation of new saline minerals. The uptake of such components may interfere with chemical and physical analysis, hindering the interpretation of the data needed to determine the identification, provenance of raw materials, formulation, and production processes of mortars, carried out in archaeometric investigations.This article discusses the presence of such mineral phases in the mortars sampled at the Kom el-Dikka archaeological site located in Alexandria, Egypt, and their effect on the findings. A multi-technique approach was undertaken to characterize the ancient mortars and determine their behaviour and evolution, by using the following analytical techniques; polarised optical microscopy (POM), scanning electron microscopy (SEM–EDS), X-ray diffraction (XRD), thermogravimetry (TG), X-ray fluorescence (XRF) and ion chromatography (IC). The results achieved through archaeometric and geochemical investigations show the presence of different mortars at the Kom el-Dikka site. Also, petrological techniques successfully explain the variation in isotopic composition (13C and 18O) patterns mediated by the presence of the saline and carbonate phases.

Alkali-activated protective coatings for reinforced concrete exposed to chlorides

The interaction of the reinforced concrete with chloride-rich environments is a predominant cause of the corrosion of reinforcing steel, which may result in the appearance of damage affecting the structural performance. One way of protecting the concrete and extending its useful life is by applying surface coatings, to limit the penetration of aggressive agents. This study evaluated the effectiveness of inorganic coatings based on alkali-activated materials (AAM) applied to concretes of Portland cement (substrate) exposed to chlorides. Two types of AAM were used, one based on volcanic natural pozzolan (70%)/granulated blast furnace slag (30%) and the other on fly ash (90%)/Portland cement (10%) added with polymeric acrylic emulsion. A mixture of NaOH and sodium silicate was used as the alkaline activator. Uncoated concrete (UCC) and commercial epoxy coating (CEC) were used as reference materials. Properties such as capillary water absorption, resistance to chloride ion penetration, adhesion strength, setting time and porosity were evaluated. The corrosion resistance of the reinforcing steel was evaluated using impressed voltage technique and immersion in NaCl 3.5%. According to the results, the AAM coatings based on volcanic natural pozzolan with 5% acrylic emulsion (by precursor weight) mortar type AMCP5 and paste type APCP5, showed the best performance. Compared to the uncoated concrete, AMCP5 and APCP5 reduce the corrosion rate following the exposure period by 86% and 96%, respectively.

Impresión 3D para la elaboración de arrecifes artificiales. Registro térmico másico

En el presente trabajo, correspondiente a la tesis doctoral en curso, se muestra la elaboración de arrecifes artificiales mediante una impresora 3D tipo Delta y el uso de estructuras auxiliares, como pallets, cercos perimetrales y arena de relleno, para lograr imprimir las formas irregulares. Como material de impresión se utilizaron dos tipos de morteros de cemento, uno con arena caliza y otro con arena de vidrio triturado. En dichos morteros se empleó cemento de bajo contenido en Clinker, se incorporó fly ash como adición y se empleó árido reciclado, lo cual dotó a los moteros de sustentabilidad o bajo impacto ambiental. En los arrecifes artificiales seregistró la temperatura interna y de borde para conocer su evolución durante un período entorno a los 5 días. Estas determinaciones se realizaron en dos piezas de la misma forma y con distintos morteros, además se evaluó una pieza prismática maciza. Los resultados muestran que la metodología empleada para la elaboración de piezas irregulares fue adecuada, ya que el modelo digital de los arrecifes artificiales se pudo reproducir en forma fidedigna y no se registró asentamiento del mortero durante el proceso. En cuento a las temperaturas registradas, se observó un aumento de temperatura superior a los 50º C en el interior, y superior a 40º C en el borde, este comportamiento fue muy similar en ambos tipos de morteros y un poco superior en la pieza de control.

Investigation of the main and interactive effects of mix design factors on the properties of cement emulsified asphalt mortars using Mixture Design of experiment

This study investigated the effect of mixture components including cement, asphalt emulsion, sand, and water on mechanical and rheological properties of Cement Emulsified Asphalt (CA) mortars (type I and II). For this investigation, compressive strength, elastic modulus, segregation, fluidity (J funnel), and spread diameter and time (specific to type II mortar) tests were performed on fresh and hardened specimens. SEM technique was also employed to inspect the micro-structure of CA mortars. To study the effect of mix design factors and their interactions in the domain where rheological and mechanical requirements are met, the Mixture Design method was used in conjunction with the D-Optimal algorithm to design the experiments and analyze the results. After assuming a quadratic model for the relationships between response variables (mechanical and rheological properties) and independent variables (mixture components) including the main effects and two-way effects, 15 randomized mix designs were obtained for each type of mortar (30 mix designs in total). The test of compressive strength was performed on cubic 50 × 50 × 50 mm specimens at the age of 7 and 28 days. The Elastic modulus of the mortars was determined from the strain-strain diagram pertaining to the 28-day compressive strength specimens. Segregation was evaluated by the use of cylindrical 50 × 50ϕ specimens. Tests of fluidity, spread diameter, and spread time were performed according to the standards of the Ministry of Railways of China. The experimental results were used to develop the estimation models of the responses, and the effect of factors and their interactions on mechanical and rheological properties were studied at 95% confidence level. The estimated statistical models could accurately predict the performance of the mortars and were therefore employed to find the optimum combinations of mixture components. Trace and ternary contour plots were drawn to analyze and discuss the effects of mixture components and their interactions on the behavior of type I and type II mortars in each experiment. Finally, the superposition principle was used to combine the responses collected from the experiments, and a series of optimum mix designs based on low, moderate, and high cement contents were devised for both types of mortar.

The Thermal Parameters of Mortars Based on Different Cement Type and W/C Ratios.

This study examines the thermal parameters of mortars based on different cement type and water-cement W/C ratios. The presented relationships are important from the point of view of thermal insulation of the entire building component, of which the mortar is a part. The thermal properties of the mortar, and in particular its dependence on the degree of moisture, is important information from the point of view of hygrothermal simulations of building components. The moisture effect on the thermal properties was tested using nine mortar types. The study consisted of producing nine types of mortar on the basis of three cements (CEM I 42.5R, CEM II A-S 52.5N, CEM III A 42.5N). For each cement type, three variants of specimens were prepared which differed according to their water/cement ratio (0.50, 0.55 and 0.60). The main research of thermal parameters was carried out using a non-stationary method based on the analysis of changing heat flux readings. The thermal conductivity, volume-specific heat and thermal diffusivity values were analyzed. The tests performed allowed for determination of the density of specimens, water absorbability and thermal parameters in three water saturation states: dry, natural and wet. Additional microstructural tests were performed using mercury intrusion porosimetry. The obtained parameters were used to determine the relationship between the measured properties. An adverse effect of dampness on the thermal insulation of the studied materials was confirmed. In extreme cases, the increase in thermal conductivity due to material high moisture was 93%. The cement used affects the relationship between the total specific surface area and the W/C ratio. As expected, the total porosity of specimens was higher for mortars with higher W/C ratios. A strong correlation has been demonstrated between the total surface area and thermal conductivity. The opposite results were obtained when assessing the relationship between the total specific surface area and water absorbability. In case of specimens CEM II A-S 52.5N, the relation was the proportional, and in specimens CEM III A 42.5N, the relationship was inversely proportional to the W/C ratio.

Consequences of aircraft operating conditions at military airbases: degradation of ordinary mortar and resistance mechanism of acrylic and silica fume modified cement mortar

Concrete pavements at military airbases are often subjected to extreme aircraft operating conditions such as exposure to high thermal shocks and hydrocarbon fluids, which cause premature degradation and loss of strength. As part of this research project, we replicated aircraft operating circumstances, and investigated their consequences on plain cement mortar as well as on a special type of cement mortar that was prepared using cement, acrylic emulsion (AE) and silica fume (SF). All mortar specimens were repetitively exposed to aircraft operating conditions, which involved the application of aviation oils and high temperature for a short period, both separately and simultaneously. Although AE and SF modified fresh mortar showed saponification during the initial stage of hydration and had a detrimental effect on the compressive strength; the modified cement mortar showed significantly better resistance to the considered harsh conditions as determined by the residual compressive strength. Moreover, the crystalline minerals in AE and SF modified cement mortar were less attacked, decomposed, and found more durable compared to the plain mortar under the extreme conditions. Thus, the study elucidates the degrading mechanisms of plain cement mortar and the added resisting mechanisms of better performing AE and SF modified cement mortar under a replicated military airbase circumstances. This study also suggests limiting the dosage of AE into cement mortar to limit the observed negative impact on compressive strength.

Numerical Simulation of Water Transport in Unsaturated Recycled Aggregate Concrete

The old mortar attached to recycled aggregate (RA) is the main reason for the difference in water movement between recycled aggregate concrete (RAC) and natural aggregate concrete (NAC). In this study, considering the old and new interfacial transition zones (ITZs), a five-phase composite model for describing the water transport and distribution in RAC is established at the mesoscale. The key parameters describing water unsaturated transport in two types of mortar, saturated hydraulic conductivity (Ks) and van Genuchten model parameters (α, n), are obtained through the constant-head permeability test and isothermal adsorption test. By using the finite element method, the numerical simulations of unsaturated moisture movement in the homogeneous mortar, NAC, and five-phase RAC are systematically carried out. The proposed moisture transport model in the matrix is validated by comparison with the available experimental findings from the literature. The results show that the model can well predict unsaturated water transport in cement-based materials, including RAC. A parameter sensitivity analysis is undertaken to ascertain the main influencing factors of water transport in RAC. It is concluded that the RA replacement rate (Rra), the thickness of the old mortar (dm), and the aggregate volume fraction (Fa) are the primary parameters affecting moisture movement in RAC.

Influence of exposure environments and moisture content on water repellency of surface impregnation of cement-based materials

Water repellent treatment is one of the effective means to improve the durability of concrete. This paper aims to investigate the water repellency of cement-based materials treated with silane-based water repellent agent under different exposure environments. Five different exposure conditions were applied in this experiment, namely, standard moist curing room, in-door laboratory atmosphere, pre-oven-dried condition, and out-door natural environment with or without shelter. Three different types of mortars with water-to-cement ratios of 0.4, 0.5 and 0.6 were prepared. And three different dosages (200, 400, 600 g/m2) of silane gel were utilized on the surface of specimens. The impregnation depth and water absorption after hydrophobic treatment have been measured. Results indicate that the initial moisture condition of mortar has a significant influence on the efficiency of surface silane impregnation. The depth of silane impregnation gradually decreases with the increase of initial moisture condition. The water repellency of surface impregnation of cement-based materials was well exhibited under the condition of about 50% relative humidity. It illustrated that the moisture within the cement-based materials affects the hydrolysis reaction process and the formation of hydrophobic membrane. Thus, the water repellency of cement-based materials greatly depends on the initial moisture content and the thickness of hydrophobic layer.

Thermal Action on Normal and High Strength Cement Mortars

High temperature effect on cement-based composites, such as concrete or mortars, represents one of the most important damaging process that may drastically affect the mechanical and durability characteristics of structures. In this paper, the results of an experimental campaign on cement mortars submitted to high temperatures are reported and discussed. Particularly, two mixtures (i.e., Normal (MNS) and High Strength Mortar (MHS)) having different water-to-binder ratios were designed and evaluated in order to investigate the incidence of both the mortar composition and the effects of thermal treatments on their physical and mechanical properties. Mortar specimens were thermally treated in an electrical furnace, being submitted to the action of temperatures ranging from 100 to 600 °C. After that and for each mortar quality and considered temperature, including the room temperature case of 20 °C, water absorption was measured by following a capillary water absorption test. Furthermore, uniaxial compression, splitting tensile and three-points bending tests were performed under residual conditions. A comparative analysis of the progressive damage caused by temperature on physical and mechanical properties of the considered mortars types is presented. On one hand, increasing temperatures produced increasing water absorption coefficients, evidencing the effect of thermal damages which may cause an increase in the mortars accessible porosity. However, under these circumstances, the internal porosity structure of lower w/b ratio mixtures results much more thermally-damaged than those of MNS. On the other hand, strengths suffered a progressive degradation due to temperature rises. While at low to medium temperatures, strength loss resulted similar for both mortar types, at higher temperature, MNS presented a relatively greater strength loss than that of MHS. The action of temperature also caused in all cases a decrease of Young’s Modulus and an increase in the strain corresponding to peak load. However, MHS showed a much more brittle behavior in comparison with that of MNS, for all temperature cases. Finally, the obtained results demonstrated that mortar quality cannot be neglected when the action of temperature is considered, being the final material performance dependent on the physical properties which, in turn, mainly depend on the mixture proportioning.

Cost-effective analysis of textile-reinforced mortar solutions used to reduce masonry infill walls collapse probability under seismic loads

The present work aimed to perform a cost-effectiveness analysis of using textile-reinforced mortar based-solutions for strengthening masonry infill walls in the RC buildings’ envelopes to reduce their OOP collapse probability. Therefore, this study starts by analyzing the effectiveness of textile-reinforced mortar based-solutions in two experimental campaigns available in the literature. Thereafter, the efficacy of the TRM is available in terms of strength, deformation and energy dissipation capacity. Influence of the textile mesh tensile strength, different types of frame-connectors and different types of mortars is discussed. The second component of this study is the cost-analysis of each TRM solution tested in these testing campaigns when compared to their efficiency during the tests. The cost of each solution is deeply analysed, estimation of the percentage of each component is computed. Finally, it is presented a case study of an 8-storey RC building structure in which its construction costs is presented according to three different locations in Portugal according to the EC8 seismic region. The costs of three different post-earthquake scenarios are analysed: i) minor damaged; b) moderate damaged; and c) extensive damages of the buildings’ envelopes.

THE INFLUENCE OF DOSAGE AND PRODUCTION PROCESS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF AIR LIME MORTARS

Abstract. This paper studies the influence of five different factors affecting the dosage and production process of seven types of air lime mortars on their physical and mechanical properties. Such factors comprise the water/lime ratio, the aggregate type and size, the material of the mold and the curing conditions. Moreover, some physical and mechanical properties, not usually measured on air lime mortars, are obtained, such as open porosity, splitting tensile strength, fracture energy and elastic modulus measured through prisms. The results show that under the three different water/lime ratios tested, the material experiences a structural weakening. Ambient curing conditions were more favorable for air lime mortars than high humid ones. Moreover, it is observed that fabrication with wooden molds provided higher mechanical properties as they absorbed the free water, although this effect was probably local. Air lime mortar with an aggregate size of 2 mm had lower consistency in a fresh state as finer sands were more water demanding and the mechanical properties of this mortar were slightly lower than those of mortar with aggregate sizes of 0/4 mm. Furthermore, using limestone aggregates improved the continuity between the lime and the matrix. This fact resulted in higher mechanical properties of the mortars with limestone aggregates in comparison to those with river sand when maintaining the same water/lime ratios. This study can suppose a further step in the improvement of the dosage methodology of air lime mortars.

Investigation and development of sound absorption of plasters prepared with pumice aggregate and natural hydraulic lime binder

Historical structure properties and indoor requirements should be taken into consideration in plaster layer mixture type selection during the historical building restoration. In the research, it has been aimed to increase the sound absorption coefficient in plaster layers with the direction of accurate restoration application decisions. In the plaster content, natural hydraulic lime binder which is frequently used in historical building restoration was researched and the pumice aggregate type instead of river sand aggregate was investigated to show the effect of lightweight aggregate type. The experimental analyses which are sound absorption, compressive strength, flexural strength, capillarity of water absorption and open porosity, were performed to compare different plaster layer types. The effects of aggregate combination volumetric ratio, polypropylene fiber ratio, flax fiber ratio, and crumb rubber additive ratio were analyzed. It was understood that sound absorption coefficients can be enhanced by means of the mortar mixture content changes and the use of lightweight aggregate type. Especially, the use of pumice aggregate instead of river sand aggregate in the mortar mıxture can significantly increase the sound absorption coeffıcıent in the range of 1400–2700 Hz. Also, the use of pumice aggregate instead of river sand aggregate has increased compressive strength and flexural strength remarkably in this research. It was especially observed that the use of additives which are listed as polypropylene fiber, flax fiber and crumb rubber in the mortar mixture, can be a very effective method to increase sound absorption performance not only in high frequencies but also low frequencies. As a result, the sound absorption research based on different mortar mixture types in plaster layers were systematically conducted to increase sound absorption coefficients in accordance with the historical building requirements.

Experimental study on the vertical interface of thin-tile masonry

This article presents the results of an experimental study on the structural behaviour of the vertical mortar thin-tile interface in thin-tile masonry. Four compression tests involving two- and three-leaf prisms made of two different types of mortar were carried out. The Digital Image Correlation (DIC) technique was used to capture the full-field displacement of the mortar thin-tile interface. The experimental results revealed that, while all the leaves presented a similar deformation in the longitudinal direction, transversally, the deformations tended to separate the mortar and tile leaf. Thus, it could be concluded that the failure mode of the thin-tile masonry was due to tensile stress perpendicular to the vertical thin-tile mortar interface (mode I), which seemed to be associated with the transverse deformation of the horizontal mortar joints. An analytical approach for the compressive strength of thin-tile masonry based on the usual equation available in the literature for unreinforced multi-leaf masonry walls has been presented. This model seems suitable for determining the compressive strength of thin-tile masonry, but has a more relevant role for mortar leaf.

Novel methodology on direct extraction of the strength information from cementitious materials using piezo-sensor based electromechanical impedance (EMI) method

It is critical to develop an accurate non-destructive testing (NDT) methods to evaluate the real-time concrete strength gain due to the fast pace of construction. Among the NDTs for concrete strength monitoring, piezoelectric materials based electromechanical impedance (EMI) method has attracted much attention recently. Some statistical approaches are proposed for impedance signal processing, such as root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD). However, these methods require the baseline value for calculation, which is not convenient, particularly for the very early strength gain monitoring. In this study, three features extracted directly from phase angle spectrum, including resonant frequency of the first local phase angle peak (PARF), local phase angle peak value (PA), and the corresponding width of half-prominence (HPW) are employed as indicators to monitor the strength gain process. Among these three indicators, the first peak of phase angle resonant frequency (PARF) is found the most reliable. The PARF index can directly be obtained from the impedance spectrum without baseline calculation. Five types of different cement mortar with various water-to-cement ratios from 0.38 to 0.46 were prepared. The EMI test and conventional cubic testing (ASTM 109) were conducted concurrently at a very early age (4th to 8th hour) and an early age (1st, 3rd, and 7th day). To examine the correlation between the compressive strength obtained and the EMI-PARF indices, a linear least-squares regression analysis was performed. Furthermore, the finite element analysis (FEA) was conducted to discuss the relationship between the features obtained from the phase angle spectrum and the stiffness of the host structure. The PARF index exhibits a high correlation with the mechanical properties of cementitious materials. Both experiments and FEA results ascertain that piezoelectric-based EMI coupled with the PARF index is a reliable method for in-place strength gain evaluation of cementitious materials.

Hygrothermal assessment of four insulation systems for interior retrofitting of solid masonry walls through calibrated numerical simulations

The present research project investigates the hygrothermal performance of four insulation systems for internal retrofitting solid masonry walls with embedded wooden wall plate and beam end. The study was carried out through numerical simulations calibrated with 2–4 years of measurements and material data from a large field experimental in the cool, temperate climate of Lyngby, Denmark. The experiment comprised two 40-foot insulated reefer containers reconfigured with 24 1 × 2 m holes, accommodating the solid masonry walls. The calibrated simulation models were used to investigate several untested design variations which included alternative brick and mortar types, masonry and insulation thickness, indoor moisture load and future climate conditions. The findings indicate that a reduction of the indoor moisture load would improve the hygrothermal performance in the interface between wall and insulation, and in the embedded wooden elements. Increased masonry thickness was seen to make the hygrothermal conditions worse due to increased drying time for the built-in moisture, while in the case of low initial moisture content, increased masonry thisckness improved the hygrothermal performance in the interface and embedded wooden elements. Increased insulation thickness also made the hygrothermal conditions worse. Regarding the brick and mortar types, the results showsed increased relative humidity in the critical locations in the case of high cement mortar compared to low cement mortar. The brick type was however found not to impact the relative humidity levels considerably. Robustness against future climate conditions was seen only for two of the four insulation systems, when combined with exterior hydrophobisation.

Experimental investigation of the unconfined compressive strength characteristics of masonry mortars

Mortar plays a major role on the strength and durability characteristics of masonry structures. While the mortar is in confined state in masonry, generally the unconfined compressive strength is assessed for quality control and strength assessment of masonry. Subsequently there are several testing methods available across different standards to determine the unconfined compressive strength of masonry mortars. Therefore this paper presents the outcome of the experimental programme conducted to empirically correlate the unconfined compressive strengths of masonry mortars determined through various testing methods. The compressive strength data of mortars were developed through testing of mortar cubes (50 mm and 70 mm), prisms (160 mm × 40 mm × 40 mm), cylinders (100 mm dia × 200 mm) and slates extracted from masonry joints (50 mm × 50 mm × 10 mm). Consequently to develop a comprehensive database to correlate the mortar compressive strengths determined through different testing methods, following variables were considered (1) mortar types (2) water to cement ratio (w/c) (3) age of testing and (4) curing conditions. Subsequently from the compressive test data obtained from the testing programme, strength correlations between different testing methods were established and presented. Furthermore simplified analytical stress-strain relationship for masonry mortars under unconfined compression is also proposed. The verification of the proposed analytical model was carried out using the experimental data obtained and the proposed simplified analytical model showed good agreement with the experimental data.