Ecological Mortars Research Articles

Ecological mortars produced from sustainable hydrated lime obtained from biomass ash

Sustainable hydrated lime is produced from biomass ash rich in calcium carbonate, with properties similar to industrial hydrated lime. However, there is a lack of current and relevant research on sustainability related to the use of alternative limestone, derived from waste such as biomass ash. In this sense, the present research aims to study the behavior of cementitious coating mortars with partial and total replacement of industrial hydrated lime by sustainable hydrated lime, through microstructural, macrostructural, physical and chemical tests. Microstructural analyses performed by SEM demonstrated the presence of cement hydration products (CSH and ettringite) in all mortars evaluated. Chemical analyses through XRF and XRD showed similarity in chemical composition and crystallographic phases between the mortar with industrial hydrated lime and the ecological mortars. The FTIR showed chemical bonds characteristic of cement mortars in all ecological mortars, ratified by TG/DTG, which shows the decomposition of products such as CSH, ettringite, portlandite and calcite in all ecological mortars. Through the results found, the viability of replacing sustainable hydrated lime with industrial hydrated lime in the preparation of ecological mortars stands out, at the optimum percentage of 50 %, with possible total replacement (100 %) without significant losses in resistance.

Cement Mortars Based on Polyamide Waste Modified with Fly Ash from Biomass Combustion—A New Material for Sustainable Construction

The article presents an analysis of the possibility of using the waste of polyamide 6 modified with fly ash (in the amount of 5, 10 and 15%) from the burning of wood–palm kernel shells biomass as an addition to cement mortar. Fly ash from the burning of biomass in a circulating fluidized bed boiler (which currently has no practical use) was first used to produce polyamide 6, and then post-production polymer waste (added at 20, 40 and 60%) was used to produce ecological mortar. The use of this type of waste is both economically profitable and desirable due to the need to implement waste material management processes in a closed circuit. The addition of polyamide 6 waste containing 5% fly ash in amounts of 20 and 40% and waste containing 10% ash in 20% to cement mortars improves their mechanical properties. The compressive strength of cement mortars (after 28 days of maturation) containing 20 and 40% of polyamide waste containing 5% fly ash increases by 6.6 and 4.6%, respectively, and the flexural strength by 4.9 and 3.4% compared to the control mortars. However, the compressive strength of mortars with the addition of 20% polyamide waste containing 10% fly ash increases by 4.2% and the flexural strength by 3.7%. Cement mortars modified with waste are characterized by slightly lower water absorption and mechanical strength after the freezing–thawing process (frost resistance) compared to control mortars and do not have an adverse effect on the environment in terms of leaching metal ions.

Corrosion of ribbed carbon steels in ecological mortars and its influence on their rotative fatigue behavior

Ribbed carbon steel rebars were embedded in mortars manufactured with three different eco-friendly binders (alkali-activated slag, and slag and fly ash-based hybrid cements) and with a commercial cement (CEM IV). This research evaluates the corrosion of reinforcements, fully assessed by natural diffusion, and its impact on the fatigue performance of the bars. Results obtained after 17-month corrosion testing on reinforced innovative mortars reveal that different pit morphologies and locations appear on the bars depending on the mortar composition, with the extent of the attack being related to the pH and the free-chloride content in each mortar. Rotative fatigue tests of the corroded bars have proven that the reduction of the fatigue life is dependent on the global extent of the corrosive attack, when the shape and distribution of the pits correspond to those generated exclusively by chloride diffusion in mortars. Bars corroded in alkali-activated slag and CEM IV mortars shown the best fatigue performances.

Ecological mortar using dried and burnt WWTP sludge

In order to create alternatives for the disposal of sludge generated in wastewater treatment plants and contribute to reducing the environmental impacts generated by the construction industry, the aim of this work was to evaluate the technical feasibility of partially replacing cement in the production of mortars by the sludge produced at the Bragança WWTP. The sludge was characterized in relation to pH, moisture, total solids, and organic matter content, and underwent different preparation processes (4) before being incorporated into the mortar. M1: The previously dried sludge was burnt for 0.5 hour at 300 °C and for 3 h at 900 °C. M2: The sludge was dried for 24 h at 105 °C. M3: The sludge was dried for seven days by solar exposure. M4: The sludge was dried for 15 d by solar exposure. After sludge preparation, it was triturated and incorporated into the mortar mixture; the proportions of sand and water were 54 and 14%, respectively. The slurry was incorporated at concentrations of 0, 3, 5, 7 and 10%. The specimens were molded for the flexural and compressive strength tests. The specimen with 7% sludge of the M1 treatment obtained the best resistance, surpassing the standard; the specimens with sludge of the M2, M3, and M4 treatments showed similar results. The incorporation of sludge resulted in mortars within the specification of the EN 998-1:2018 norm in relation to compressive strength and, consequently, has technical feasibility.

Rheology of eco-friendly mortars - Effect of industrial wastes additions

– Mortar is a mixture of sand, cement, water and eventually additives. With the environmentalissues, mortars are increasingly formulated with mineral additions as a substitute for cement in order toproduce ecological mortars. It is one of the most widely used cementitious materials in the field ofconstruction and civil engineering after concrete. Mortar placement techniques are evolving day by day,such as pumping, spraying and injection. Therefore, knowing the rheological behavior of mortars becomesmore and more crucial to master their implementation techniques. This study presents the development ofa vane rheometer to estimate the plastic viscosity yield stress of mortars. The rheological parameters weredeveloped from measurements using a procedure to convert data from moment torque and rotational speedto shear stresses versus shear rate. The procedure used considered the locally sheared material as a Binghamfluid and calculated the characteristic shear rate from the quilt analogy. The device was tested with threeexperimental programs in which many rheological parameters of the compositions of different mortars werecalculated. The results obtained validated the developed rheometer test procedure and confirmed that thetest results are reproducible and repeatable. Measurements were made on different compositions of mortarof each mineral addition, altering the amount of blast furnace slag (BFS) and fly ash (FA) in order toevaluate the impact of supplemental cementitious materials and industrial wastes on the rheologicalcharacteristics (plastic viscosity and yield stress) of eco-friendly mortar..

Incidence of recycled aggregates and ternary cements on the compressive strength and durability of ecological mortars

This research presents the effect of substituting natural aggregates by recycled aggregates and cement blended with limestone by coal ashes on the compressive strength and durability properties of an ecological mortar. Firstly, the industrial wastes (recycled aggregate from concrete and coal ash) were characterized using physical, chemical, and mineralogical techniques such as x-ray diffraction (DRX), particle size distribution (PSD), and electronic scanning microscopy (SEM). Secondly, the maximum substitution of blended cement for coal ash was defined based on the compressive strength in order to obtain a ternary cement. Subsequently, the mortars with ternary cement and different dosages of recycled aggregate were made, these mortars were evaluated through compressive strength and sulfate attack resistance (durability). The results found show that the inclusion of these by-products improved mechanical properties due to the chemical affinity between the recycled aggregates and the ashes. The contents of old adhered mortar in recycled aggregates made more susceptible mixtures to be attacked by the magnesium sulfates. This phenomenon was studied through SEM and sulfate attack test. Finally, the expansion exhibited by the samples manufactured with recycled aggregate and coal ash did not reach the limits for the initial degradation of the material. That is, ternary cements, such as those used in this research, when mixed with recycled aggregates, allow the production of ecological concretes and mortars with excellent mechanical behavior and resistance to sulfate attack.

Eco-friendly gypsum-lime mortar with the incorporation of recycled waste brick

To reduce the consumption of cement and thus mitigate the negative impact of its manufacturing industry on the environment, the use of traditional gypsum and lime binders, with less environmental impact, was adopted in this work for the preparation of an eco-friendly mortar. Furthermore, recycled waste brick was incorporated as a replacement for sand to promote the recycling of construction and demolition waste on one side, and to reduce the depletion of natural sand resources on the other side.In this paper, the effect of the amount of lime, gypsum, and brick powder on the mortar properties was investigated. To this end, eight mortars were prepared using gypsum, lime, and gypsum-lime binders with and without brick powder. The replacement percentage of sand by brick powder in the gypsum-lime mortars was 33% and 66%. A cement mortar was also included for comparison purposes. It was observed that increasing the percentage of gypsum in gypsum-lime mortars improves bond, flexural, and dry compressive strengths but results in more porous structure and less resistance in the saturated state. Although the replacement of 66% of sand by the brick powder in mortars containing 66% of gypsum as binder increased the capillary absorption rate, it provided less dense mortars with a much better bond strength than cement mortar. It also improved the mechanical strength and especially the saturated strength compared to the mortar without brick powder addition. This improvement can be attributed to the formation of new CASH/CSH phases. The mortar containing 66% of gypsum as binder and 66% of brick powder as aggregate can be a very promising alternative towards an ecological mortar with less impact on the environment.

Recycling of ashes from thermal stations for the production of an ecological mortar: New application in civil engineering

The main idea of this work is to investigate about the flexural and compressive forces of the mortar, which was developed from fly ash, hearth ash, and magnetized water with different times of magnetization. The results of this work reveal that the flexural and compressive force of mortars realized with magnetized water is higher than those prepared with non magnitezed water. The best result of increasing the flexural and the compressive forces of the mortar are obtained when the water magnetization time is equal to 20 min. The growth in flexural and the compressive forces of the mortar elaborated with magnetized water is proportional to the magnetization time.

Valuation of fly ash: new horizons for an ecological mortar based on magnetized water application in building materials

Resources natural are limited and run out over time. The building construction sector uses a large number of nature reserves. In previous years, several researchers have attempted to formulate an environmentally friendly mortar from waste materials such as fly ash. In this study, an ecological mortar was developed by replacing some of the cement with fly ash. Various tests were performed to determine the mechanical properties of normal mortar and fly ash (FA) mortars. In this current research, the study was conducted in three different stages. In Phase I, An eco-friendly mortar was manufactured by replacing part of the cement with fly ash powder and replacing tap water (TW) with magnetised water (MW). In Phase II, the Taguchi method and JMP Trial 15 software were used to optimise the design of the mixture. In Phase III, samples of the optimised mixture were cast for testing to confirm the resistance to bending. In addition, the study was extended to analyse the microstructural properties of mortars characterised by SEM. Itwas concluded a 10% replacement of a part of the cement by fly ash powder and replacement of (TW) by (MW) was found to be optimal and can be used appropriately for green mortar design.

Characterization of different biomass ashes as supplementary cementitious material to produce coating mortar

Abstract Despite being characterized as a renewable energy source, burning biomass is an environmental problem regarding the disposal of generated by-products. The present work aimed to determine the main properties of Rice Husk Ash, Sugarcane Bagasse Ash and Eucalyptus Chip Ash to evaluate their impacts on the production of ecological mortars with lower cement consumption levels. Therefore, the physical-chemical characterization of biomass ashes and flexural and compressive strength tests, dynamic elastic modulus and capillary water absorption of the mortars produced with 10, 20 and 30% substitution, by mass, of Portland cement were carried out for each of the biomass ashes. It was found that the chemical and mineralogical characteristics presented by the biomass ashes had a significant impact on the results obtained. Considering the high levels of amorphous silica, RHA allowed high levels of substitution without affecting the mortar’s physical and mechanical parameters. Although not very reactive, SCBA and ECA maintained the performance of mortars at low levels of incorporation, acting as filling materials (fillers). The results are encouraging for paving the way in terms of using different biomass ashes in rendering mortars.

Mechanical Behavior of a Composite Lightweight Slab, Consisting of a Laminated Wooden Joist and Ecological Mortar.

The investigation reported in this paper is an evaluation of the mechanical behavior of full-scale ecological mortar slabs manufactured with a mixture of expanded clay and recycled concrete aggregates. The composite mortars form a compressive layer over laminated wooden joists to form a single construction unit. To do so, full-scale flexural tests are conducted of the composite laminated wood-ecological mortar slabs with different types of mortar designs: reference mortar (MR), lightweight mortar dosed with recycled concrete aggregates (MLC), and lightweight mortar dosed with recycled mixed aggregates (MLM). The test results showed that the mortar forming the compression layer and the laminated wooden joists worked in unison and withstood a higher maximum failure load under flexion than the failure load of the wooden joists in isolation. Moreover, the laboratory test results were compared with the simulated values of the theoretical model, generated in accordance with the technical specifications for structural calculations contained in the Spanish building code, and with the results calculated by a computer software package. From the analysis of the results of the calculation methods and the full-scale laboratory test results, it was concluded that the safety margin yielded by the calculations validated the use of those methods on this type of composite slab. In this way, a strong mixed wood–mortar slab was designed, contributing little dead-load to the building structure and its manufacture with recycled aggregate, also contributes to the circular economy of construction materials.

Ecological Design of New Efficient Energy-Performance Construction Materials with Rigid Polyurethane Foam Waste

An ecological mortar is designed from industrial sub-products, with the objective of utilizing both the slag residues, generated during steel manufacturing processes, and the waste from Polyurethane Foam (PF) panels, generated during refrigerator chamber manufacturing processes. The ecological mortar design involves the dosing of Electric Arc Furnace (EAF) slag, together with finely ground Polyurethane Foam, cement, and additives. An energy efficient prefabricated block is designed with the mortar, for use in construction, and its energy performance is assessed as a material inserted within the envelope of a service sector (hospital) building, either as an exterior skin, or as an enclosing component within the façade interior. The main contribution of this research is the characterization of the thermo-physical and mechanical properties of a new prefabricated panel made with recycled materials. The full characterization of the properties of these new materials is presented and discussed. The new prefabricated panel demonstrates adequate thermo-mechanical characteristics as a substitute for traditional materials, while improving the sustainability of the building. As a secondary objective, the energy behaviour of the new panels when integrated in a real building is presented by means of a case study simulation. The use of computational thermal simulation confirmed that the properties of the prefabricated block influenced the annual thermal demand of the building for heating and cooling. Improvements to the thermal inertia of the building envelope were also confirmed with the inclusion of PF waste, giving the mortar an energy performance that was similar to conventional materials, in such a way that its use in façade construction may be validated, in addition to its environmental benefits, due to it having been manufactured with critical recycled industrial waste such as EAF slag and PF, thereby contributing to both the circular economy and sustainable development.

The influence of partial replacement of natural sand aggregates by grits residues on the mechanical properties of an ecological mortar

The great technological development has significantly increased the production of industrialized goods and the volume of mineral resources exploited. Consequently, there was a huge increase in the amount of waste produced daily throughout the world. For instance, the production of cellulose by the Kraft process results in large amounts of grits residues, solid industrial wastes with high potential of environmental contamination if not properly treated. Therefore, the objective of this study was the evaluation of the effects of partially replacing the natural sand aggregate of an ecological mortar by different percentages of grits residue on the compressive strength, flexural strength and tensile bond strength of the material. Three percentages of grits residue were used in this experiment to partially replace the aggregates: 10, 15, and 20%, as mass percentage, respectively. Data were statistically analyzed using the MINITAB 18.0® software at a significance level of 5%. The replacement ratio of sand aggregates by grits residues have great influence on the flowability of recycled mortar. The best flexural response was obtained when the sand aggregate was replaced by 15% grits residues. These results indicate the potential of using this residue as a partial replacement of fine aggregates in coating mortars, and suggest that 15% can be considered the ideal replacement ratio.

Can an earth plaster be efficient when applied on different masonries?

Earth mortars are known for being ecological but also reversible, contributing to comfort and aesthetic. Nevertheless, compatibility with different masonries is scarcely assessed. A commercial unstabilised ready-mixed earth mortar was produced with an ilitic earth with addition of sand and oat straw fibres. It was used to plaster different experimental masonry walls, at protected outdoors environmental conditions. The plasters applied on the masonries were visually monitored and characterized in situ by non-destructive techniques and in laboratory by bulk density and microstructure. The same mortar used for the plasters was characterized in laboratory in fresh state and, after drying, on prismatic specimens and specimens composed by a mortar layer applied on hollow bricks. Some variation of results occurs when the same unstabilised ready-mixed earth mortar is used to plaster different masonries, what may be related to the water absorption of the masonry materials. However, after six months the earth plaster presented durability on the different masonries when protected from rain. It proves that this ecological mortar is technically efficient to plaster different types of masonry, historical or contemporary.

Lime-cement mortars designed with steelmaking slags as aggregates and validation study of their properties using mathematical models

In this paper, ecological masonry mortars as a new building material are design, using a mix of calcium lime and Portland cement as binder, together with steelmaking waste aggregate (Electric Arc Furnace Slag and Ladle Furnace Slag), in substitution of natural aggregate and, subsequently a comparative study was made using mathematical models. To do so, different reference mortar types were prepared with various proportions of calcium lime CL-90-S and Portland Cement CEM I 42.5 R as binder, together with a natural siliceous aggregate. Subsequently, and separately, the natural siliceous aggregate (NA) was progressively substituted by LF and EAF slags. The mixtures designed were analyzed in the laboratory through characterization tests (European Standard), and a comparative study was made with the reference mortars. Surface Response Methodology (RSM) was applied to test whether the mathematical model could acceptably predict the behaviours of these types of mortars, analytical process that allow predicting the behaviour of a material without having to complete the entire series of necessary laboratory tests. Comparing the results obtained in the laboratory and those estimated through mathematical models RSM of each of the properties, it can be affirmed that the methods of mathematical prediction were useful for the study of these ecological mortars for use in construction.

Recycling of plastic waste materials in the composition of ecological mortars

Today, the wish to maintain and improve living conditions worldwide has led to a particular focus on ecology issues in all areas of activity, including construction. The research demonstrates that it is possible to solve major problems in the management of plastic waste materials by recycling, and to obtain new building materials. In this study, the optimal recipes for the manufacture of ecological mortars by PVC waste recycling were established. Mortars containing PVC waste have the advantage that their production is less polluting, as it does not involve high energy consumption. The study presented in this paper is finalized with the development of new building materials.

Recycling of Polystyrene Waste in the Composition of Ecological Mortars

Abstract As part of sustainable development, an important objective of constructors is the elaboration of a technology that may lead to the manufacture of new building materials and their implementation so as to contribute to the protection of the environment and natural resources, as well as to the creation of healthy living conditions. This study presents technologies for the manufacture of new building materials by polystyrene waste recycling. The following are produced: an ecological plastering mortar whose thermal conductivity is three times lower than that of ordinary mortar, which recommends it as a thermal insulation plastering mortar; three thermal insulation fillers, of which one is also recommended to be used as panels for external thermal insulation systems. All these are supported by the results obtained following the laboratory determinations presented in the paper.