Masonry Mortars Research Articles

Characteristics of Masonry Prepared with KM Soil as Fine Aggregate in Cement Mortar and Concrete Block

Manufactured Sand (M Sand) has become a viable alternative for the river sand in the construction industry as a potential fine aggregate. The M Sand poses environmental implications as it is produced by crushing natural resources like stones. The extensive use of M Sand may also lead to a reduction in availability due to the depletion of natural rocks in the days to come. Hence, this study attempts to assess the feasibility of utilizing the clayey soil containing Kaolinite – Montmorillonite (KM) as a predominant clay mineral, as a replacement to the Manufactured sand in the preparation of cement mortar and cement block that are used in masonry construction. In the case of concrete block masonry units, the M Sand is replaced by 25%, 50%, and 100% with KM Soil, and an attempt is also made to produce the mortars by completely replacing the M Sand with KM soil. Further, the properties of the concrete blocks and mortars prepared with KM soil are assessed and compared with the ones prepared with M Sand. Also, the performance of the stack bonded masonry prisms like compressive strength and bond strength in shear is assessed for the various masonry prism prepared with combinations of the Concrete block masonry units and mortars. The results indicate that the stack bonded masonry prism assemblies with KM soil both in cement mortar and concrete block have performed moderately well in compressive strength and shear bond strength in comparison with the one prepared with M Sand.

Economical and eco-friendly masonry mortar containing waste concrete powder as a supplementary cementitious material

Research on the feasibility of using waste concrete powder (WCP) as a replacement for cement in mortar production is available in the literature. However, the WCP-mortar related studies are centered on the material characterization and the performance of the mortars. For sustainability purposes, the mortars should provide the required strength as well as the economic and environmental benefits. Hence, the aim of this study is to evaluate the properties of cement masonry mortar containing WCP, along with their economic and environmental advantages. In the experimental study, mortars were prepared by replacing ordinary Portland cement (OPC) with WCP in various fractions of 0%, 15%, 30%, 40%, 60%, 75%, and 100% by mass. The influence of WCP on the fresh and hardened properties of the mortars was examined. It was found that the strengths of the masonry mortars were reduced significantly as the quantity of WCP increased, yet mortar mixtures containing 40–75% WCP met the strength criteria for masonry mortar. Also, using WCP resulted in tremendous reductions in the cost and environmental factors of the mortars. In conclusion, the mortars provided the specified strength requirement for masonry work as well as economic and environmental gains, making them sustainable.

Seashells to lime: swotting of a vernacular method and needs for revival

Lime is the versatile mineral. Various forms of lime are used in environmental, metallurgical, construction, chemical/industrial applications, and more. It has been used for masonry mortars and plastering for centuries. Lime is usually obtained from lime stone. Places like Kerala where lime stone is scarce, lime is majorly obtained from seashells so they developed their own traditional method to extract lime. Shell lime was one of the major components in construction of most of the houses, temples, bridges, dams etc. in Kerala during the earlier days. People used shell lime not only as a replacement to cement but also as a plastering agent which helps to reduce temperature in the interiors. This dissertation is retrospection into the vernacular method of making lime mortar from seashells by visiting the workspace. The study also intends to analyse the challenges faced by this method and provide with necessary recommendations.

Compressive and Flexural Strength of Non-Hydraulic Lime Mortar with Slag (GGBS)

Mortar for masonry is important because it provides the bond between masonry units so enabling the composite to behave as a single material. The type of mortar used determines the flexural and compressive strength of the masonry. Currently, most mortars used in construction are cement based. However, due to the heavy energy-intensive processes that are involved in its production the cement industry is responsible for up to 10% of global CO2 emissions; therefore, there are serious environmental implications with the usage and application of cement mortars. A sustainable alternative are lime mortars which have 30% less embodied CO2. Lime mortars confer benefits in comparison to cement based mortars such as accommodating a greater degree of wall movement and improved damp resistance. The main disadvantage with lime mortars is the longer setting time which can take up to 91 days in addition to the low strength. A way to overcome this is to add cement replacements e.g pozzolans or slag. This paper investigates the properties of non-hydraulic (lime putty) lime mortar containing up to 20% ground granulated blastfurnace slag (GGBS). Findings show a minimal amount of GGBS addition of 2% doubles the mortar strength to 2 MPa within 91 days with an eventual strength of over 15 MPa achieved with 20% GGBS. Strengths satisfying minimum requirements for all four mortar designations were achieved with between 2 - 16% GGBS addition, all within 56 days ageing; with designations (i), (ii), (iii) & (iv) strengths being satisfied within 28 days. Therefore, non-hydraulic lime mortars with GGBS offer a more sustainable alternative to cement based mortars without compromising setting time or strength whilst offering improved flexibility and breathability

A review on utilization of recycled concrete aggregates (RCA) and ceramic fines in mortar application

Recently, the construction industry has greatly focused on using sustainable products during construction. Cement, coarse aggregates, and river sand are the primary consumables during any building construction. This study conducts a systematic and extensive literature analysis of numerous publications published over 20 years from 2003 to 2022. The impacts of integrating recycled concrete aggregates (RCA) and Ceramic waste are studied for both the rendering and masonry mortar. The various properties of mortar, such as its fresh state properties, mechanical and physical properties and durability-related behaviour, are analysed. The significant findings suggests that increasing the content of RCA as natural river sand replacement reduces the mechanical performance as well as the durability properties of the mortars. However, the durability and mechanical features of the mortars are improved when ceramic fines from diverse sources are included as a partial replacement for natural river sand. The study concludes that the RCA can be used up to 20–25 % and ceramic fines up to 40 %. This review highlights the prospect and potential of such construction industry wastes in mortar applications.

Elaboration of a blended binder based on marls from phosphate mines waste rocks

This paper investigates the properties of a mixture design of three tender marls as a binder. The used marls are by-products of open-pit phosphate mine. At first, ten mixtures with diverse combinations of calcined marl (CM) were blended with cement at a ratio of 1:1. The properties of those blends were tested including hydration kinetics, setting time, and unconfined compressive strength (UCS) at different ages of curing. The findings confirm the reactivity of those marls and their contribution to the developed strengths by hydraulic and pozzolanic activity. Despite the higher incorporation of CM (50 %), some of the blended binders reached a strength index activity (SAI) higher than 75 % at all the curing age. This qualifies those blends as supplementary cementitious materials (SCMs). The findings imply that whatever the proportioning mixture of the marls, in a mix of 1:1 with cement, the UCS could achieve 17–26 MPa, 23–36 MPa, and 34–50 MPa at 7, 28, and 91 days, respectively. After optimizing the mixture proportioning of marls, their incorporation rate was varied and studied. The results showed that the optimal CM with a substitution rate of 20 wt% had the highest strengths at all the curing age with a SAI to the reference of 153, 138, and 127 % at 7, 28, and 91 days respectively. The incorporation of 40 wt% of the optimal CM led to a slightly higher and comparable results to the reference without mitigating the UCS. Blends with 40–80 wt% of optimal CM substitution rate could be used as a binder for masonry mortar. Upper this incorporation rate, 100 % optimal CM revealed a good self-reactivity that achieved 10 MPa at 28-d can be used as a binder for repairing historical building.

A comparative study on the mechanical and acid resistance characteristics of ambient temperature-cured glass waste and fly ash-based geopolymeric masonry mortars

A comparative study on the mechanical and acid resistance characteristics of ambient temperature-cured glass waste and fly ash-based geopolymeric masonry mortars

Internal Sulphate Attack in Masonry Mortars with Thaumasite Formation.

The present paper focuses on the study of mortar samples where expansions with thaumasite formation occur as a consequence of sulphate attack. The samples correspond to a masonry mortar used in a rural construction located in the Spanish province of Toledo made of cement with limestone filler addition CEM II/AL. Composition and microstructure of the mortars have been analysed by means of scanning electron microscopy (SEM) using secondary and backscattered electrons (BSE) and X-ray diffraction (XRD). The results show that aggregates are contaminated with gypsum, which is the source of the sulphates for the internal attack. It seems that thaumasite is formed through an ettringite transformation where aluminium atoms are replaced with silicon atoms by means of a solid solution. The study highlights that thaumasite can be formed in warm weather through an internal sulphate attack due to gypsum contamination of aggregates.

The formation of porous light ceramsite using Yellow River sediment and its application in concrete masonry production

The accumulation of large amounts of sediment in Yellow River has posed a threat to the local ecological environment. In this study, Yellow River sediment was used as the main raw material to prepare lightweight ceramsite and masonry mortar. The effects of pulverized coal addition, calcination time, and calcination temperature on the microstructure of ceramsite were investigated. The effects of the amount of raw materials, concentration of glutinous rice slurry, and substitution amount of ceramsite (as opposed to standard sand) on the properties of masonry mortar were then studied. For a pulverized coal addition of 10%, the calcination temperature was 1125 ℃, calcination time was 30 min, bulk density of the ceramsite was 879 kg m−3, water absorption was 5.9%, and cylinder pressure strength was 9.1 MPa. When the mass ratio (hydrated lime: Yellow River sediment: standard sand) was 3:4:2, glutinous rice slurry with a concentration of 3% was added and then cured in a curing box at a temperature of 25 ± 2 ℃ and humidity of 95 ± 2% for 28 days. The surface hardness of the obtained masonry mortar was 97 HA, and the unconfined compressive strength was 1.1 MPa. After 28 days of curing with ceramsite instead of standard sand, the surface hardness of the masonry mortar was 94.5 HA and the unconfined compressive strength was 0.91 MPa; this indicated that the standard sand can be completely replaced by ceramsite, thereby effectively increasing the utilization rate of Yellow River sediment. This work provided a feasible method for efficient utilization of Yellow River sediment resources.

Experimental investigation of semi-interlocking mortarless masonry-infilled frames

Masonry-infilled frames (MIFs) are a common construction form in many parts of the world. The presence of mortared masonry makes structural frames relatively stiff resulting in limited displacement capacity and unintended torsional forces that have been responsible for catastrophic destruction of buildings during several past seismic events. An alternative infill material solution is using semi-interlocking (mortarless) masonry (SIM), which is associated with controlled in-plane sliding. Five small-dimensioned specimens, including one bare frame and four SIM-infilled concrete frames were constructed and subjected to cyclic displacements. The variable parameters included specimen aspect ratio, vertical load on frame members, and grouting of masonry.A detailed description of the construction procedure and the testing of material properties used in the experiments are presented. The damage patterns associated to each of the specimens are explained to investigate their deformation modes and to identify the drift thresholds corresponding to the damage in the MIFs. A modified idealisation model is proposed that is suitable for SIM-infilled reinforced concrete MIFs. Critical structural properties of MIFs that include the yield strength, energy dissipation capacity, initial stiffness and ductility are obtained from the idealisation model and the force-displacement relationship. These properties are compared and contrasted against the specimens and also to the traditional MIFs with the relevant data extracted from literature. From the observed damage and the force-displacement relationship, Performance Levels of the MIFs are established. Compared to traditional MIFs, the SIM-infilled MIFs are shown to have significantly smaller initial stiffness and larger performance level drift thresholds.

Recycling plastic wastes in order to obtain new building materials

This paper presents the development of new types of construction materials using plastic waste. According to the European Court, plastic waste from various sectors such as the automotive, electronics, agriculture and construction sectors is a growing problem and is damaging to both terrestrial and marine media. Thus, every year, between 4.8 and 12.7 million tons of plastics reach the oceans. According to most of the research studies, plastic wastes have the potential to replace the natural aggregate at specific percentages. This paper proposes the reuse of this waste as reinforcement in masonry mortars, using plastic waste in various proportions. The experimental program follows the characteristics of masonry mortars both in terms of the behaviour of fresh mortar and in terms of mechanical strength. The results obtained showed a better performance of mortars reinforced with plastic strips, both in terms of flexural strength and compressive strength.

Performance and durability of self-compacting mortar with recycled sand from crushed brick

The demolition of brick masonry structures and the rejected non-conform bricks are generating a great volume of brick residues. The use of recycled sand from brick residues in the production of mortar could decrease the amount of waste going into landfills and reduce the consumption of natural resources. This paper investigated the feasibility of using recycled sand from crushed brick (RBS) in the self-compacting mortar (SCM). The crushed limestone sand was partially replaced with RBS at different levels (0, 5, 10, 25 and 50%). The properties at fresh state, mechanical behavoir, drying shrinkage and durability of SCM were discussed. As the substitution of limestone sand by RBS increased, the compressive strength of mortars slightly reduced at the age of 28 days (3.3% and 16.9% lower than the reference mortar, respectively for 25% RBS and 50% RBS content); however, which is within the compressive strength requirement in European standard EN 998-2 for masonry mortars. The incorporation of RBS in SCM showed better resistance to chloride diffusion, whereas more attention should be paid to carbonation and sulphate attack. The results indicate that it is possible to manufacture SCM by partially replacing the crushed limestone sand with RBS up to 25% replacement level.

Influence of relative humidity on the strength and stiffness of unstabilised earth blocks and earth masonry mortar

Aim of this study is to provide information about moisture dependent material behaviour of unstabilised load-bearing earth blocks and mortars. Compressive strength and Young’s modulus were investigated after conditioning in varying relative humidity reaching from 40% up to 95%. The material composition and physical properties were investigated to understand the influence of relative humidity onto the mechanical properties. A normalisation of strength and stiffness by the values obtained at 23 °C and 50 % relative humidity reveals a linear dependence of compressive strength and Young’s modulus that is regardless of the material composition. Thus, it is possible to describe the influence of relative humidity onto the load-bearing behaviour of unstabilised earth masonry materials in a generally valid formulation.

Analytical model for CFRP confined masonry columns subjected to monotonic and cyclic compression

Confinement of masonry columns using fibre reinforced polymer (FRP) composites have displayed to enhance the axial capacity and ductility. Although, mechanisms of FRP confined masonry column (CMC) subjected to monotonic compression loading with various configurations have been investigated and rational design rules were developed, the response of FRP-CMC under cyclic compression is not widely researched. Therefore, this paper presents an analytical stress–strain model for FRP-CMC subjected to cyclic compression based on the experimental data generated through a testing program. The experimental program has been executed in this research by testing twelve masonry columns confined with discontinuous FRP sheets subjected to monotonic and cyclic compression. The masonry columns were assembled with two varieties of masonry bricks and mortars. The data from the testing of discontinuously CMCs and previous experimental program involving twenty-four continuously CMCs were employed to analytically predict the cyclic compression characteristics. The testing results of discontinuously CMCs subjected to axial monotonic and cyclic compression have shown that they are quite different in terms of their strength and deformability compared to continuously CMCs. The discontinuous FRP strengthening columns resulted in strength and ductility increments in the range of 100–150% and 60–80%, respectively. For the analytical model, the envelop curve, plastic strain, stress deteriorations in cycles, unloading and reloading segments of the proposed stress–strain model have been verified against the experimental data. It has been shown that the suggested analytical model is capable of describing the cyclic axial stress–strain characteristics of FRP-CMCs.

Recovery of Mineral Wool Waste and Recycled Aggregates for Use in the Manufacturing Processes of Masonry Mortars

The environmental problems caused by industrial waste are of a universal nature. In this sense, achieving an adequate management of construction and demolition waste has become one of the great challenges of today’s society. This work studies the possibility of recovering mineral wool thermal insulation waste for its reincorporation into the manufacturing process of masonry mortar. To this end, an experimental campaign has been conducted with mortars made with natural aggregate and two types of recycled aggregates: concrete and mixed ceramic, in which mineral wool fibers are incorporated as a partial replacement of sand in percentages of 0%, 10% and 20%. The results show that, although the traditional mortars offer better technical performance, the mortars made with recycled aggregate present adequate viability for use on-site. Furthermore, it has been concluded that the incorporation of recycled mineral wool fibers in the mortar matrix decreases the thermal conductivity and shrinkage during the setting of these materials, increasing their mechanical flexural strength and durability.

Анализ дефектов несущих конструкций производственного здания

All buildings with a significant service life must be regularly surveyed. This work analyzes the results of the inspection of the building of the compressor shop KC-1. Analysis of the design documentation and the results of measurement work showed that structurally the building has overall dimensions in plan along the outer axes of 21.0 × 72.0 meters. The height of the building is 17.0 meters. The conducted visual examination showed the presence of damages and defects of the third and fourth categories, which requires an instrumental examination. In particular, the need to determine the strength of brickwork and the strength of concrete in structures. The analysis of the results of the instrumental examination showed: the results of testing the wall masonry by the shock pulse method using the ONIKS 2.5 device showed that the compressive strength grade of the silicate brick of the compressor shop walls corresponds to M75 and M125, and ceramic M100. The grade of the masonry mortar for the walls of the compressor shop corresponds to M50 and M75; The results of concrete testing by the non-destructive method of strength control using the DigiShmidt2000 device showed that the compressive strength class of concrete in the reinforced concrete columns of the workshop corresponds to B20, in the girders B25, floor slabs and coating slabs B20. Verification numerical calculations on the computer of the bearing capacity of the building structures of the compressor shop building were performed taking into account the actual static diagrams, sections of elements, strength characteristics of materials established during the survey, and constant loads existing at the date of the survey. Based on the results of the verification calculation of the building structures of the transverse frame of the building, it was found that the bearing capacity of the upper chord of the truss was not provided. The bearing capacity of the building columns when calculating according to the first and second groups of limiting states is provided. In general, the analysis showed that the technical condition of the technical condition of the compressor shop KC-1 is unacceptable.

Performance of Sustainable Mortars Made with Filler from Different Construction By-Products.

One way to contribute to sustainability in the construction sector is through the incorporation of construction by-products from their own activities. This work intends to extend the possibilities for enhancement of these by-products through the incorporation of four different ones, as fillers, in mortar production. The influence of these incorporations in mortar production was compared with a reference mortar with siliceous filler in its fresh state; workability, entrained air content and fresh density, and in its hardened state; capillary water absorption, water vapour permeability and shrinkage (up to 91 days); and adhesive, compressive, and flexural strength; the last two were studied over time (up to 180 days). Despite the reduction in compressive strength, both in the short and long term, there was a gain in adhesive strength when the construction by-products were incorporated. Regarding the physical properties and durability studied, no relevant differences were found with respect to the reference mortar. According to the European Specifications, these mortars could be used as regular or coloured rendering and plastering mortars, and masonry mortars, and these findings promote the circular economy in the construction sector.

Comparative Study of Effects of Air-Entraining Plasticizing Admixture and Lime on Physical and Mechanical Properties of Masonry Mortars and Plasters.

This article presents research on selected physical and mechanical properties of cement-based plasters and masonry mortars with consistency-improving additives, namely, traditional hydrated lime and a plasticizing and aerating mixture (APA), which, in practice, is often considered to be a lime substitute. Comparative analysis of the properties of mortars with alternative additives—lime or APA—was carried out, taking into consideration possible effects of cement, as two types of Portland cement were used for the research. For fresh mortar, mixture consistency, air content, resistance to segregation, and water retention were determined. Tests on hardened mortars included tests of porosity and impermeability, depth of penetration of water under pressure, drying shrinkage, as well as compressive and bending strength, modulus of elasticity, and adhesion of mortars to the base. In addition, research has shown that cement–lime mortars and cement mortars with APA admixture of similar consistency in the fresh state are characterized by significantly different properties. The results show, in most of the features analyzed, more favorable properties of mortars with the use of traditional lime. For shrinkage only, the use of admixture turned out to be more advantageous.

Biological testing as an important stage of preparation of the building materials for the further use

The level of environmental safety is determined by the methods and techniques used to implement them. One of the promising areas for determining the assessment of dehydrated waste used in the construction industry is biological testing, which include the use of environmentally hazardous substances, in the form of an extract, to determine the danger degree of the samples and their further use in different areas of construction.
 Ensuring environmental safety in general is an important component in any industry. Solving issues of industrial safety, the use of hazardous tests in technology reveals the leading idea, which is considered in the scope of presenting the research results on the preparation and use of dehydrated waste from industrial enterprises.
 It is experimentally established that liquid dehydrated wastes of galvanic production are used in the manufacture of the building materials of different complexity and subsequent use. The obtained data for construction products input and heat-treated sludge (g / dm3), masonry mortars (%) and reinforced concrete with the addition of sludge (%) is only the first stage in the construction industry. The next stage is the manufacture of more responsible products ceramic tiles with the addition of sludge (%) and asphalt with the addition of sludge (%), which requires more responsible testing i.e. under critical operating conditions.
 The results of biological testing are aimed at determining the following parameters at: Dunaliella-degree of immobilization for 5 days. (%); Elodéa canadénsis - the degree of inhibition of growth in length (% to control) at exposure (d.) and Daphnia - survival at 48 days of exposure (%).
 To determine the level of environmental safety of building materials obtained from dehydrated waste of galvanic production, it is possible to accurately provide an assessment of their biological condition.
 The issues of ecological safety, safety of the natural environment, which is an important condition for the water complex of the country, using water and water resources in the technological processes of the water treatment and use systems are considered.

Effects of post-fire curing on the residual mechanical behavior of cement-lime masonry mortars

Cement-lime mortars have been largely employed in contemporary masonry structures. Although usually analyzed under high-temperature conditions, their behavior over the post-fire curing time is often neglected. This paper addresses an experimental program that evaluated the influence of post-fire curing on the residual mechanical behavior of masonry mortars. Three distinct mortar mixes were subjected to standard fire tests and exposed to ambient air at different post-fire curing ages. After fire exposure, mechanical tests assessed the stress–strain diagrams of fire-damaged mortars. According to the results, an increase in post-fire curing time reduced mechanical properties and increased deformability, mainly for mortars with high lime content. The mortars showed a progressive deterioration and a more ductile behavior throughout post-fire curing. The paper also introduces a theoretical model with some correlations that showed good agreement in predicting the post-fire mechanical behavior of masonry mortars.