Conventional Mortar Research Articles

Design and properties of eco-friendly binary mortars containing ash from biomass-fuelled power plants

The use of biomass to produce electric power and heat will intensify in the years to come, in pursuit of sustainable growth. Stockpiling the vast amounts of fly and bottom ash generated in that process wastes resources and has an adverse impact on the environment.The viability of bottom ash as a supplementary cementitious material in new eco-efficient cements is studied, including its effect on binder chemical, rheological, mechanical and microstructural properties. The findings show that these additions induce improvements in later age mechanical performance relative to conventional mortars. An ANOVA conducted to determine the impact of waste type, replacement ratio and curing time on compressive and flexural strength reveals that the latter two have a significant effect on mechanical properties. The new cements meet the requirements laid down in EN 197-1 for CEM II/A and CEM IV/A cements, making them apt for use in construction.

Effect of water film thickness on the flow in conventional mortars and concrete

Mortar and concrete can be divided into two phases of solids and water, where water fills the voids between the grains and also coats the surface of the particles. The current study investigates the influence of the thickness of coating water on flow spread of mortars and concrete. The article aims at correlating consistency of concrete to consistency of mortar using the concept of excess water layer theory. It was found that the flow behavior of granular mixtures can be directly related to the average water film thickness that envelops the particles. The concept was tested on mortars and concrete mixtures with different cement types, aggregate grading, aggregate shape, fineness and proportioning; proving water film thickness to be the most critical parameter affecting the flow. The results of the study indicate the possibility of predicting the flowability of mixtures by knowing the thickness of the water film that envelops the grains. In addition, the relation between flowability of mixtures measured in different sizes of slump cone is explored to enable translating flow of mortars measured in mini-slump cone to flow of concrete obtained from Abrams’ cone.

Blast furnace slag-based geopolymer mortars cured at different conditions: modeling and optimization of compressive strength

The sustainable growth in construction industry is moving towards exploration of alternative cements. The current research deals with preparation of geopolymer mortars based on granulated blast furnace slag as partial replacement of cement based on using central composite experimental design. The effect of the activated alkaline binder (geopolymer/cement ratio, 8.6–86.4 wt.%) and the alkaline liquid/solid proportion (0.38–0.45) on the compressive strength and density of geopolymer mortars of age 7 days were investigated. The geopolymer mortars were cured at different conditions (ambient temperature, water curing for 6 days followed by 1 day heat curing at 80 °C and heat curing for 1 day at 80 °C after 6 days air curing at ambient temperature). The compressive strength was modeled and optimized by analyzing the experimental data using response surface methodology. The results obtained confirmed that optimum compressive strength was achieved with geopolymer/cement ratio 8.6% and liquid activator/solid 0.52. The heat curing seemed to associate with the higher compressive strength and density. New geopolymer mortars cured by heating for 1 day could be prepared with an increase of 26.6% in compressive strength compared to conventional Portland cement mortars.

Influence of fluidity on mechanical and permeation performances of recycled aggregate mortar

Abstract The use of recycled fine aggregates in making mortar is an effective measure to increase the social and ecological values these days due to the pressing issues associated with the over-exploitation of natural sand as well as disposal of construction and demolition wastes. To counteract the synergetic effects of W/C ratio, recycled fine aggregates quality and its content, fluidity was considered as parameter to formulate the recycled aggregate mortar. The experimental results of this investigation elucidate the effectiveness of fluidity on mechanical and permeation performances of recycled aggregate mortar. A comparison with the outcomes of conventional mortar is also presented. The experimental outcomes reveal that, recycled aggregate mortar requires additional amount of water to attain the same fluidity of controlled mortar due to inferior characteristics of RFA, such as high initial water absorption and volume of voids with in mortar. The setting characteristics of recycled aggregate mortar were influenced by the fluidity, recycled fine aggregates quality and its content and their setting times were earlier than that of controlled mortar. However, recycled aggregate mortar corresponding to the fluidity of 110 ± 2.5 mm and 160 ± 2.5 mm attained lower strength characteristics, lower pulse velocity value, higher permeable void content, higher water absorption by immersion and higher sorptivity than those associated to the fluidity of 135 ± 2.5 mm. Therefore, recycled aggregate mortar associated to the moderate fluidity of 135 ± 2.5 mm is feasible and exhibits better mechanical and permeation performances.

Promotion of circular economy: steelwork dusts as secondary raw material in conventional mortars.

Among the actions proposed by the European Union for the implementation of Circular Economy is the use of waste as a secondary raw material (SRM). During the fusion of the scrap, a steel dust is generated, named electric arc furnace dust (EAFD). The EAFD is composed mainly of potentially leachable heavy metals and is classified as a "hazardous" waste. Worldwide, approximately 70% of EAFD is deposited in landfills, with a previous treatment through cement-based materials to prevent the metals' mobility. However, this action is not in accordance with the Circular Economy concept. The present investigation analyses the use of EAFD as SRM in conventional mortar production for its use as a construction material. Different substitution percentages (25, 50 and 100%) were used replacing the siliceous filler by EAFD. A preceding characterisation of the waste by X-ray fluorescence, X-ray diffraction, specific surface area, bulk density, electron microscopy and particle size distribution was performed. The investigation analysed the behaviour of conventional mortars by tests of workability, compressive strength, mineralogy, water absorption by capillarity, and leaching behaviour in granular and monolithic states. The results obtained indicate a slight improvement in mechanical behaviour with the incorporation of EAFD, the reason why its use as SRM in conventional mortars would benefit the construction industry and would encourage the Circular Economy. From an environmental point of view, the mechanisms of Pb fixation should be improved in a granular state.

Determination of Mechanical Properties of Mortar by Using Fine Crushed Glass (FCG) and Waste Rubber (WR)

Concrete contain more amount of cement which will release more CO2 and effects the environment, therefore to reduce the amount of cement in a concrete one should have approach towards replacement of cement with other waste and cost effective material such as glass. Since waste glass is not biodegradable and therefore alternative usage of it is required. Such can be used as coarse aggregate and substitute of cement constituents in concrete and mortar. Also disposal of waste glass into landfills is one of the major issues that have been come across. This study aims on reducing such problems by the usage of waste glass as one of the replacing material in cement mortar. The pozzolanic activity of glass powder and properties of glass powder blended cement were evaluated. Also the mechanical and chemical properties of such blended mortar has been evaluated. The cement is replaced 0%, 5%, 10%, 15% and 20% by glass powder content by weight of cement. The test results shows that on adding the optimum amount of waste glass the compressive strength of mortar has been increased. Also at 5% replacement of cement with waste glass powder gives the best proportion to increase compressive strength and reduce the cost of conventional mortar.

Experimental Investigation of Basalt Textile Reinforced Engineered Cementitious Composite under Apparent Hoop Tensile Loading

Over the past decade, conventional mortar reinforced by textile has shown a promising performance as a composite material for repairing of both concrete and masonry structures compared with that of reinforced by discrete fibres. However, the relatively brittleness of the conventional mortar adversely affects the efficiency of the textile reinforced mortar (TRM) composite system due to the premature textile fracture. Engineered cementitious composite (ECC) is a well-known high-performance cementitious composite for its superior tensile strain-hardening properties and high impact resistance compared with both conventional mortar and discrete fibres reinforced mortar. In this paper, the behaviour of ECC reinforced by basalt textile was investigated and compared with that of TRM technique. The behaviour of ring-shaped specimens subjected to apparent hoop tensile loading was studied. The response characteristics including: tensile strength, failure modes, energy absorption, toughness index, strain behaviour, and the correlations between tensile strength and energy absorption were investigated. The results revealed that ECC is a promising material that can effectively enhance the performance of textile reinforced mortar. Replacing conventional mortar by ECC resulted in a notable increase in the peak tensile load by 241% indicating a dramatic effect of the ECC-based matrix.

Synthesis and characterization of concrete mortars reinforced with thermostable polymer from industrial waste

DOI: 10.7764/RDLC.17.3.465 The present research is focused on synthesizing and physically characterization different mixtures of concrete mortar reinforced with thermostable polymers from industrial waste. The mortars were made from the homogeneous mixture of cement, gravel, and water with additions of polyepoxide in different percentages. This polymer carried a milling process to obtain particle sizes of 1, 2 and 3mm. The mixtures were emptied in cubic bronze molds (5cm side) without vibrating compaction and allowed to stand for 24 hours before being removed. Ten mortars were prepared by mixture and they were cured in water for 28 days at room temperature before being characterized. Subsequently, the weight, compression strength and thermal conductivity of the samples were measured. The best results were for the mortars with additions of 100% polyepoxide (without gravel) and 3mm particle size, with a compression strength of 76.6kgcm -2 (higher than that required in mortars, 70kgcm -2 ), a thermal conductivity of 0.68Wm -1 K -1 (59.93% less than conventional mortar, 1.70Wm -1 K -1 ) and a weight of 141g (33.80% lower than the traditional mortar, 213g). According to the results obtained, a reliable alternative is presented to reuse waste material in the construction industry, replacing gravel by polyepoxide polymer particles in the process of manufacturing masonry elements providing the final product with the characteristics of lightness, thermal insulation, and acceptable compression strength, through simple, economical and sustainable processes.

Rubberized mortar: The influence of aggregate granulometry in mechanical resistances and acoustic behavior

The incorporation of rubber waste from tires into cementitious elements has become an increasingly recurrent practice, since this activity fosters the idea of sustainable construction. The use of rubber as an aggregate in the mortar promotes the correct destination of this residue, becoming inert, promoting the hygiene of the environment. Many researchers have studied the physical and mechanical behavior of rubberized mortar. However, particle geometry analyzes are scarce. This research aims to study the incorporation of rubber tire residues in mortars in two grades of granulometry, i.e., spheroids (S) and fibers (F), replacing the conventional aggregate in 7.5%, 15% and 30%. Density, compressive strength, flexural strength, microstructure and sound attenuation tests were performed. Rubber mortars showed a reduction in density of up to 34.6% compared to conventional mortar, consequently resulting in a reduction of approximately 4 times in compressive strength. However, there is a better acoustic behavior, especially when the rubber is used in fiber format, which presents 29.70% and 42.54% of attenuation enhancement for 15% of fiber waste tire rubber, considering P- and S-waves, respectively.

Reuse of fly ash and bottom ash in mortars with improved thermal conductivity performance for buildings

An approach towards effective utilization of fly ash and bottom ash in the construction of energy efficient buildings has been presented in this paper. Two masonry mortar grades MM3 and MM5 were considered for trial mix. Portland pozzolana cement with substitution of sand by fly ash and bottom ash separately in different substitution ratios (SR) were adopted for preparation of test samples. Fly ash and bottom ash with lime dust and marble dust combinations were also tested as sand free mortars. 28 days compressive strength, apparent porosity, bulk density and thermal conductivity parameters were evaluated for all such samples. By analysing the test results, it was observed that all the SR combinations satisfied the minimum masonry mortar grade MM0.7, as per IS 2250. Both the MM3 and MM5 grade mortars could be produced at 60% SR by fly ash, and corresponding reductions in thermal conductivity values were 69%, and 54% respectively, while compared with conventional mortar. Sand less mortar for both the grades resulted around 57% reductions in corresponding thermal conductivity values. Overall heat transfer co-efficient (U-value) for both side plastered and rendered brick masonry wall panel was found to be reduced by 15.58%, while comparison made between conventional mix of MM5 grade and corresponding 50% fly ash substituted mix. Thus such ash blended mortar mix appears to be advantageous in building envelop application for lowering the overall cooling/heating demand of building, besides utilizing the coal ash up to largest extent and saving natural mineral sand from depletion.

Mechanical properties, durability, and life-cycle assessment of concrete building blocks incorporating recycled concrete aggregates

This paper aims to explore the possible use of recycled concrete aggregates (RCAs) to produce concrete building blocks. Laboratory test and plant trial were carried out to manufacture concrete building blocks incorporating 75% RCAs. A series of tests were conducted to investigate the mechanical and durability properties of the recycled aggregate concrete (RAC) blocks. The compression and shear performances of masonry prisms built with RAC blocks and conventional mortars were experimentally studied too. Furthermore, the environmental impact of RAC blocks was studied using life-cycle assessment (LCA) method. Five different environmental impact categories (i.e., GWP, AP, EP, HTP, POCP) are calculated and comparatively analyzed. The effect of RCAs on the mechanical and durability properties, as well as the environmental impact of RAC blocks was investigated. The test results indicate that the incorporation of RCAs slightly declined the compressive strength and impaired the durability of the concrete blocks. Nevertheless, concrete building blocks incorporating 75% RCAs satisfied the strength, drying shrinkage and freeze-thaw resistance requirements for concrete building blocks specified by Chinese standard. The compressive and shear performances of masonry prisms constructed with RAC blocks are similar to those of conventional concrete masonry. RAC blocks have less environmental impact compared to normal concrete blocks. It is feasible to use RCAs to manufacture concrete building blocks along with environmental benefits. The use of RAC blocks plays a key role in ending the building life cycle and will improve the sustainable development of masonry structures.

Preliminary Analysis of the Influence of Reinforced Mortar Coating on the Compressive Strength of Clay Bricks

Introduction: This paper presents an extensive characterisation of materials and components used in non-structural masonry constructions in the region of Pernambuco, Brazil. Methods: An experimental study was carried out on a running bond of red clay prisms, of two and three ceramic blocks, with and without cement mortar coating, subjected to axial compression in order to enhance the capacity of masonry. Results and Conclusion: The experimental preliminary results indicate an increase both in the compressive load capacity of the coated prisms and in those that use coatings based on reinforced mortar, not complying with the specifications of conventional structural mortar.

Experimental Study on the Physical Properties of Mud Mortar in Comparison with the Conventional Mortars

Experimental Study on the Physical Properties of Mud Mortar in Comparison with the Conventional Mortars

Study of mechanical properties and recommendations for the application of waste Bakelite aggregate concrete

Bakelite waste from industrial manufacturing may be a hazard to the environment and public health. The utilization of waste Bakelite (WB) to replace natural aggregates (NA), such as natural coarse aggregate (NCA) and natural fine aggregate (NFA), in concrete and mortar is an approach for reducing both waste plastic and natural material. This research examines the utilization of waste Bakelite aggregate (WBA) in concrete and mortar mixtures to form waste Bakelite aggregate concrete (WBAC) and waste Bakelite mortar (WBM). The tests cover the physical and chemical properties of WBA, the mechanical properties of WBAC and WBM (including the extraction of chemical substances from WBA utilization to replace NCA and NFA), and recommendations for the application of replacement. The results indicate that WBA particles of different sizes can replace both fine and coarse natural aggregates. Its weight is less than natural aggregate but the absorption rate is higher. As for recommendations for the application, it was found that replacing 20% of NCA with waste Bakelite coarse aggregate in concrete (WBAC-RNCA) was the most suitable proportion, owing to its mechanical properties and safety for the environment and public health, and because its material cost is acceptable. However, the use of waste Bakelite fine aggregate to replace NFA (WBAC-RNFA) in concrete is not appropriate, because its mechanical properties are not sufficient, and it is considered unsafe for the environment and health. Moreover, WBM is not a suitable material for plastering work, since it may be a hazard to the environment and public health, and its cost is higher than conventional mortar.

Influence of Demolition Waste Fine Particles on the Properties of Recycled Aggregate Masonry Mortar

This paper analyses the influence of the fine fraction of two types of construction and demolition waste (CDW1 and CDW2) on the properties of recycled aggregates (RA) and masonry mortars. The CDW1’s main component was ceramic while the CDW2 were concrete. Three different kinds of fine RA were produced from each source of CDW; the first type was produced by only using the fraction finer than 4.76 mm, the second one by employing only the coarser fraction than 4.76 mm, and the third type was a mix of both fractions of CDW. The masonry mortars were produced employing the 100% substitution of natural aggregates. The results show that all the recycled mortars achieved a higher water retentivity capacity than that of the conventional mortars. However, the sole use of the fine fraction of the CDW was found to have a deleterious effect over the hardened mortar properties, thus making it only adequate for the rendering or bonding of interior walls at or above ground level. In contrast a combination of both the fine fraction and coarse fraction of the CDW in the production of the RA achieved all the minimum requirements for rendering and bonding masonry mortar.

Revamping the traditional air lime mortar using the natural polymer – Areca nut for restoration application

The modification in lime mortar to preserve the historic structures is the growing trend in current scenario. The natural polymer, areca nut extract in concentrations of 3% and 5% was incorporated in the lime mortar to modify the fresh and hardened state properties. The microstructural analyses of the modified mortar were studied by X-ray powder diffraction, FTIR spectroscopy, SEM−EDS analysis. The results obtained from these analytical techniques are substantiated with the results of TG-DTA. Inclusion of areca nut extract in the lime mortar proves to be superior against the conventional mortar in mechanical, physical and durability properties.

Fresh and Hardened Properties of Self‐Leveling Mortars with Porcelain and Red Ceramic Wastes

Self‐leveling mortar (SLM) has several advantages when compared to the conventional mortar used in subfloors, especially when productivity is desired. In Brazil, the use of SLM is not still widespread related to conventional mortar. Few builders are using it in constructions. In the same way, the sustainable reuse of wastes in building materials is not so great, but it has grown, becoming increasingly important. In Brazil, a great amount of waste is generated by the manufacture of electrical porcelain insulators and red ceramic. These materials are formed mainly by amorphous silicates and aluminosilicates, which when added as cement replacement can generate pozzolanic reactions. The present study evaluated the feasibility of using such wastes to replace cement to make SLM. Mortars were studied in the fresh state (fluidity, segregation and/or bleeding, outflow rate, outflow time, and kinetics of temperature) and in the hardened state (compressive strength, flexural tensile strength, capillary water absorption, water penetration height, and air permeability). According to the results, the cement replacement by porcelain or ceramic in SLM diminishes the flow and increases the setting time. The compressive strength is higher than the minimum related to literature, and the low values of water absorption and permeability were reached with porcelain waste.

Flexural response and crack development properties of ferrocement panels reinforced with steel fibers

Effect of partial replacement of cement with silica fume on flexural strength and cracking of ferrocement simply supported panels reinforced with steel fiber and wire mesh was explored. For the purpose of this study, various dosages of silica fume and steel fiber were mechanically mixed with reference mortar. The ferrocement panel specimens were prepared with 1, 2, and 3 layers of galvanized wire mesh. The water-cement ratio was fixed at 0.35 for all the test specimens. The main objective of this study is to evaluate the 28-day flexural strength of simply supported panels by laboratory center point flexural tests. The results of 15 simply supported ferrocement panels indicated that the fabricated ferrocement panels with silica fume content up to 15% by binder weight exhibited superior flexural performance as compared to the control ferrocement panels with no silica fume content. Flexural performance parameter used for comparison was flexure stress–deflection response. The number of cracks developed at failure was also taken into account with measurements of average crack width and crack spacing. It was further revealed that for a 15% cement replacement with silica fume and 4% steel fiber addition in mortar mix, approximately 3.6-fold increase in 28-day flexural strength was observed when compared to the conventional mortar. In summary, inclusion of 4% steel fibers in a mortar of fabricated ferrocement panel improved the crack resistance and flexural capacity.

Excavated soil waste as fine aggregate in fly ash based geopolymer mortar

To explore the significance of geopolymer technology on producing environmental friendly waste based mortar which could be a sustainable replacement for conventional mortar; Low, medium and high plastic soil from different locations was used as fine aggregate to produce fly ash based geopolymer mortars. The experiments were designed using central composite design of response surface methodology. Molarity of NaOH, curing temperature and fly ash content were the key parameters considered in this study. The interaction effect of these parameters with four different fine aggregates (river sand, low, medium and high plastic soils) were identified and discussed. It is demonstrated that geopolymerisation helps in utilizing even high plastic soil as fine aggregate in construction applications. Soil based geopolymer mortar resulted in lower density range compared to conventional geopolymer of similar strength values. The test results show that strength and shrinkage properties of soil based geopolymer mortar significantly depends on the type of clay present in the soil. Geopolymer mix with each specific soil has an optimum combination of NaOH, curing temperature and binder dosage that helps them achieve the desired properties such as higher compressive strength and lower dry density, water absorption and shrinkage values.

Properties of Different Mortars and their Effect on the Flexural Strength of Low Density Block Walls

Mortar for masonry is important because it provides the linkage 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 so in this paper, a range of mortars are examined and their effects on the flexural strength of low density block walls determined. These include traditional designation (iii) (1 cement : 1 lime : 6 sand), designation (iv) (1 cement : 1 lime : 9 sand) mortars as defined in BS 5628, and two thin layer mortars. The conventional mortars were formed using both 42.5N or 32.5N PC to BS EN 197 in order to ascertain the difference these two cements have on the properties of mortar. The thin layer mortars show remarkably high compressive strength. The characteristic flexural strength of low density aircrete wallettes incorporating both these conventional and thin layer mortars was verified. The wallettes were tested in accordance with British and European standards. The flexural strength of aircrete wallettes was derived from the strength of small specimens tested to destruction under four-point loading. The strengths of the wallettes are high with impressive repeatability with the maximum strength being reached for thin layer wallettes within 7 days curing time. In general the strengths of both conventional mortar and thin layer mortar wallettes compare favourably to values reported in the standards.