Soil-cement Bricks Research Articles

Utilizing traditional knowledge and creatively repurposing mining waste to develop new sustainable products geared toward eco-friendly construction

Mining is a very important activity for civil engineering. Important aggregates are removed from this for civil construction, bridges and roads, development of construction materials and several other applications. However, this activity has negatively impacted both the exploration areas and their surroundings. Associated with this environmental concern, it is possible to enter the context of real estate paints, which emit considerable amounts of volatile organic compounds that harm the atmosphere and the health of workers and users, in addition to reducing the air quality of the environment in which they are located was applied. Furthermore, with technological advances, industrial paints with synthetic pigments began to replace natural products, causing environmental pollution. The volatile organic compounds generated by real estate paints have resulted in health problems for the population. The literature has reported a growing search for renewable paint products, such as environmentally friendly paints and other environmentally friendly products for use in construction. In this way, materials from mining waste have been studied as an alternative for the development of ecological bricks. Studies suggest that mining waste, considered an environmental liability, can be an alternative for the production of soil-cement bricks that meet technical and environmental specifications. In addition to ecological bricks, another aspect that has emerged as a viable alternative for using mining waste is the production of ecological paints and the application of possible natural pigments to diversify the colors of ecological paints. Finally, the manufacture of ecological paints, natural dyes, ecological bricks and cement from mining waste, in addition to being an environmental improvement alternative, can be used in socio-environmental projects, allowing social inclusion, teaching and reproducing environmental education, and increasing environmental awareness. In this review we address the main types of mining waste that are used in the production of bricks and paints ecological.

Between Concrete and Earth

This essay scrutinizes the soil-cement brick (SCB), a half-earthen, half-concrete building material, and its use in U.S.-aided housing projects in Cold War-era Taiwan. Made of cement and natural earth with manually operated ‘brickmaker’ machines, SCB drew American housing technocrats’ attention and was regarded as an alternative to the concrete block but a more ‘modern’ and standardizable material than mudbricks or red bricks. Since the early 1950s, American advisors attempted to engage the SCB in the ‘aided self-help housing’ model, utilizing it as an infrastructure for mortgage-driven mass homeownership in underdeveloped countries. However, the standardized manufacture of SCB proved challenging; the material’s deficient performances resulted in local homebuyers’ skepticism and resistance. Analyzing the SCB as a material that simultaneously presented the characters of the concrete block and rammed earthen structure, this essay aims to recomplicate ‘modern’ characteristics of different building materials.

Characteristics of the açai seed (Euterpe precatoria Martius) after thermal processing and its potential in soil-cement brick

The management of the açai palm, a species of the Euterpe genus, has grown in recent years mainly for the extraction of palm heart and the pulp of the fruit called açai. After the extraction of the’ pulp, there is a significant generation of residues, as the discarded seeds account for approximately 85% of the fruit. Therefore, this research aims to characterize the açai seed after fruit processing, as well as to evaluate the potential of thermally processed seed for use in soil-cement bricks. The seed morpho-anatomy tests were performed, including moisture content, loss of ignition, ash content, thermogravimetry, fluorescence, and X-ray diffraction of the ground seeds. Tests on thermally processed seeds included readings by X-ray diffraction and laser granulometry. After evaluating the properties of the ash, it was incorporated into soil-cement mixtures in proportions of 5%, 10%, 15%, and 20%, replacing the clinker content of LC3 (Limestone Calcined Clay Cement). Based on the results obtained, soil-cement bricks were produced with a composition of 90% soil and 10% LC3, with the LC3 cement clinker being replaced by 20% açai seed ash. The results indicate the potential for the application of açai seed ash in soil-cement bricks on a practical scale, demonstrating that the ash enhances soil stabilization and increases the compressive strength of the soil-cement matrix due to its smaller particle size compared to that of the soil grains. This not only reduces the amount of cement required for the matrix but also offers environmental sustainability through the utilization of seed waste. The study underscores the potential of applying açai seed ash in the context of environmentally significant alternative technologies and sustainable practices, emphasizing the promise of the properties found in discarded açai seeds.

Evaluation of mechanical, physical and chemical properties of ecological modular soil-alkali activated bricks without Portland cement

With the growth of civil construction materials to mitigate environmental impacts and meet technical demands, modular soil-cement bricks have emerged as an alternative construction material in Brazil due to economic, social, and environmental reasons. However, the composition of Portland cement still generates environmental impacts due to CO2 emissions. Thus, this study aimed to produce modular bricks through alkali activation in real scale using a mixture of clay soil and sand, metakaolin (M) or blast furnace slag (BFS) as precursors, NaOH solution as a simple activator, or compound with hydrated lime. Thermal curing effects were analyzed. Water absorption, compressive strength, XRF, XRD, SEM and EDS analysis were performed, as well as Life Cycle Analysis (LCA). All bricks presented suitable water absorption values according to Brazilian standards. Groups with metakaolin and simple activator presented the lowest compressive strength since an incomplete geopolymerization was verified; however, when a compound activator was used, the compressive strength was highly increased. The BFS group presented the best overall performance under water absorption and compressive strength with mean values of 3.6 MPa and 13.4%, respectively. Microstructural analyses confirmed the development of microstructures such as Zeolite, Calcite and Hydrated Calcium Silicate from the alkali activation reactions. Alkali activated bricks presented at least 35% less CO2 emissions compared to ceramic bricks in LCA. Modular bricks made with MK or BFS and compound activator met all the requirements for their use, showing that these mixtures can be an alternative for sustainable brick production, with the reuse of industrial waste instead of Portland cement incorporation.

ENERGY, ENVIRONMENTAL AND COST PERFORMANCE OF WALL SYSTEMS FOR STANDARD RESIDENTIAL HOUSING: A CASE STUDY

ABSTRACT The design process influences the resulting environmental impacts and life cycle costs. Life cycle assessment can assist the construction industry in selecting more sustainable technological alternatives. In this context, wall systems play a significant role in the environmental and economic performance of a building. This paper compares the potential energy, costs, and environmental impacts of three structural wall construction systems (ceramic, concrete, and soil-cement blocks) for standard residential housing in Southern Brazil, considering a 50-year lifespan. The highest environmental impacts are related to the use stage of all three systems. The ceramic brick system presents the highest impact in the product stage, the concrete block system in the use stage, and the soil cement brick system in the construction stage. The concrete block system presents the highest relative net present value, followed by soil cement and ceramic brick systems. The impacts for the soil-cement block system are similar to those for ceramic block, while the concrete block system is the most expensive, energy demanding, and CO2 releasing. The results demonstrate the importance of producing criteria for architectural decision-making based on scientific evidence when choosing wall systems.

Soil cement brick production process: literature review

Soil-cement brick is one of the most common building materials for masonry construction, although it is not the oldest. As it is a product made up basically of soil and cement, it has existed in Brazil since the appearance of cement. The brick has been gaining market share due to several characteristics: ease of production, as it can be produced at the construction site itself, ease of obtaining raw material, as the soils exist in all locations, low processing costs, and easy handling. In addition, the soil-cement brick, also called ecological brick, stands out for not harming the environment like the ceramic brick that needs to be burned. Despite being a standardized product, production procedures and properties need to be updated. As an example, the soil used is very coarse which makes it difficult for the components to react. After conformation, the cure is still carried out without humidification, not obtaining adequate resistance. Furthermore, durability has been little studied. Thus, this article presents a literature review based on research in the production of soil-cement bricks. Materials and research methods used in the process of making soil-cement bricks, as well as various properties, are discussed. The most common results are grouped. The literature review showed that the production process is well defined, although it needs improvement. As for material properties, they meet the standards. However, the entire process needs more research.

Passive of CRFS Technology in Soil-Cement Application

In Brazil, with the ban on the production, sale, and use of chrysotile asbestos, the sector’s industry opted to replace asbestos with CRFS Technology—Cement Reinforced with Synthetic Wire (fiber cement); that is, another product to be disposed of in landfills. This work aimed to determine a composite based on clay, fiber cement powder, and cement that meets the technical specifications of Brazilian soil–cement application standards to contribute to a more sustainable treatment of the future disposal of fiber cement products. With the characterization analysis of the materials, we identified that the clay granulometry is heterogeneous and distributed from 0.1 µm to 25 µm. In comparison, 75% of the fiber cement powder has grains greater than 10 µm. For clay, the liquidity limit is 39.67%, the plasticity limit is 25.01%, and the plasticity index is 14.66%. In the semiquantitative chemical analysis, silicon oxide (SiO2) and calcium oxide (CaO) stood out as the main oxides found, reflected in the mineralogy as quartz and calcium silicate. Therefore, we identified the percentage of organic matter in clay at 2%, using the result of the thermogravimetric analysis. The results described met the normative parameters foreseen for soil–cement applications. That said, the technological characterization was carried out by tests of linear retraction, water absorption, and simple mechanical compression on the specimens made under an axial pressure of 31.2 Mpa in the formulations defined in this work. The formulations with 10% cement and 20% and 30% fiber cement powder are suitable for use in soil–cement bricks, as they have volumetric shrinkage percentages from 2% to 2.5%, water absorption ranging from 18.66% to 19.39%, and simple compressions from 4.25 Mpa to 6.88 Mpa, meeting the requirements of Brazilian standards for soil–cement applications. It is concluded that the results showed that it is possible to produce soil–cement bricks with passive fiber cement products converted into powder, avoiding improper disposal and unwanted environmental impacts.

Sustainable Alternative for the Production of Soil Cement Bricks

The construction industry plays a fundamental role in the economy of a developing country, representing, in most of them, approximately 3.7% to 10.5% of its Gross Domestic Product. However, it is extremely important to search for sustainable alternatives in this sector, aiming to reduce the environmental impacts generated by the production of inputs, waste generation, in addition to the inappropriate disposal of this activity in the environment. Therefore, the work aimed to evaluate the technical and economic feasibility of the incorporation of residues (Marble and Granite Cutting Waste—MW and Construction and Demolition Waste—CDW) in the production of soil cement bricks (SCB). For the development of the present work, physical and mechanical characterization of the soil, residues (CDW and MW), composites (Control, MW15%, MW25%, MW50%, MW100%, MW30%CDW70%) were performed. After manufacturing the bricks, the characterizations mentioned were carried out at 7, 28 and 60 days, in addition to the evaluation of the geometric characteristics, water absorption and strength of the bricks and microscopic analysis of the post-rupture fragments. Additionally, a cost analysis of the use of SCB was performed compared to two different construction systems (ceramic brick and concrete block). From the results of physical characterization, soil was classified as clayey-silty sand (SC-SM), while the CDW was well-graded sand and MW as sandy clay. Soil and composite plasticity characteristics ranged from weakly plastic (MW15% and MW30%CDW70%) to highly plastic (MW100%). In the compaction tests, composites with the addition of MW presented increasing values in terms of optimal moisture. The compressive strength test performed showed satisfactory results for all composites, especially for MW25%, which obtained the most significant result with 13.777 kPa at 28 days. Thus, it is concluded that the incorporation of CDW and MW for the production of SCB represents a sustainable application for civil construction.

ESTUDO BIBLIOGRÁFICO DA VIABILIDADE DA PRODUÇÃO DE TIJOLOS SOLO-CIMENTO COM RESÍDUOS DA CONSTRUÇÃO CIVIL E A FIBRA DO COCO BABAÇU

The present work aims to verify the feasibility of producing a soil-cement brick, having as raw materials and construction and demolition waste type A and babassu coconut fiber. From the comparison of results obtained through the literature. The study presents the types of materials existing in civil construction waste that can be used in the manufacture of soil cement brick, a parallel between conventional brick and soil-cement, the processes for obtaining babassu coconut fiber, describe what are the phases and processes for the manufacture of the brick, which are the basic tests and the results found in the bibliography on the use of babassu coconut fiber and constructio n waste.

Influence of the Amount of Dimension Stone Waste on Water Absorption of Soil-Cement Bricks

This paper shows the use of dimension stone waste in the manufacture of soil-cement bricks. Initially, a sample of the soil was analyzed for mineralogical composition, particle size distribution (classifying it in the proportion of silt, sand, and clay), and physical performance by plasticity (Atterberg limits specified by standard NBR 7180). A series of soil/waste/cement mixtures were prepared with contents up to 90% wt.% of dimension stone waste. The samples were characterized as mineralogical composition, microstructure, and water absorption after 7, 14, 21, 28, and 60 days. The composition with 20% wt.% of dimension stone waste presented individual and average values of water absorption according to the conditions established by standard NBR ABNT 10834 (≤22% and ≤20% respectively) and the other samples presented similar results, indicating that the dimension stone waste could be used for production of soil-cement bricks, helping to reduce the environmental impacts of the dimension stone industry.

Is the Soil-Cement Brick an Ecological Brick? An Analysis of the Life Cycle Environmental and Energy Performance of Masonry Walls

Masonry wall is a key construction subsystem, but it embodies significant environmental and energy burdens within the life cycle of buildings. Soil-cement bricks and blocks stand as an alternative low-cost masonry material, but despite the widespread claim to be environmentally friendly, more systematic investigation is lacking. This study aimed to assess the life cycle environmental and energy performance of 1.0 m2 of a soil-cement brick masonry wall from cradle-to-construction in terms of carbon, energy, and water footprints, and fossil and mineral resource use, as well as compare it with conventional technologies such as ceramic and concrete block masonries in Brazil. Results showed that raw materials are a major contribution to soil cement masonry walls, followed by the joints and links with columns, in which cement stands out among other inputs. Hydraulic pressing in brick production had a negligible burden increase compared with manual pressing. The PVA mortar joint outperformed the PVA glue one, whereas resin coating performed better than cement mortar. In comparison with ceramic and concrete masonry walls, the soil cement masonry presented overall better environmental and energy performance and was the least affected by the inclusion of finishing coating layers and transport of materials in the sensitivity analysis scenarios, although improved scenarios of conventional options could be competitive, e.g., ceramic masonry with blocks produced by firing reforested wood for the carbon footprint. Scale-up analysis revealed that widespread deployment of soil cement masonry in the built environment would substantially avoid environmental and energy burdens compared with conventional technologies.

A year-assessment of the suitability of a green façade to improve thermal performance of an affordable housing

The urban green infrastructure has been increasingly used for sustainable design and resilient cities. Despite its many benefits, such as aesthetic enhancement, improvement of the physical and mental health of residents, especially for vulnerable youth and elderly people, or creating opportunities for social cohesion and climate regulation, green infrastructure has not been used in low-income housing in subtropical Brazil, where the temperature can reach over 40 °C along the summer. This study evaluated a full-scale, low-cost green façade over a year to assess its effect on the thermal performance of an eco-friendly affordable housing located in humid subtropical climate. Aiming to be eco-friendly and keep its cost low, the house was built with materials such as unplastered hollow soil-cement bricks, not having very good thermal performance. The Wisteria floribunda, a deciduous vine, was used in the green façade installed on a west-facing wall, adjacent to a bare wall, which was also evaluated enabling to establish the thermal difference between the shaded wall and the bare wall. In the winter, the shaded and bare walls' amplitudes were remarkably close, due to leaf shedding, a desirable feature to improve temperatures within the house. The benefits of the green façade were clearer during spring and summer when the external surface temperature of the shaded wall was reduced by up to 9 °C compared to the bare wall, and its thermal amplitude varied by 8.4 °C, while the amplitude of the bare wall was more than double this value. The plant layer diminished the heat flux through the external wall by up to 22.3 W/m2 during the summer, and 8 W/m2 during the winter. These results show the potential of a low-cost green façade to improve the thermal comfort of green affordable housing projects.

Evaluation of the Technological Properties of Soil–Cement Bricks with Incorporation of Coconut Fiber Powder

The objective of this work was to evaluate the effect of partial replacement of soil by different percentages of coconut fiber powder in the manufacture of soil–cement bricks. The reference mix ratio of 10:1 (soil:cement) in volume was used for the manufacture of bricks, in addition to the partial replacement of soil mass by 5, 10, and 15% of coconut fiber. The characterization of the raw materials was performed with the analysis of the granulometry, together with technological tests, such as mechanical compressive strength and water absorption. As a result, it was observed that the soil has 34.30% clay and 62.80% sand, characterizing a sandy-clay soil type and the coconut fiber powder was characterized as a fine aggregate. The mechanical compressive strength tests showed a decrease in their average values according to the increase in the incorporation of coconut fiber into the bricks. It was concluded that the results of the mechanical compressive strength and some of the water absorption are in disagreement with the Brazilian technical standard. This conclusion corroborates other studies that show the difficulty in standardizing reference mixtures and working with soil, which is a highly heterogeneous material.

Thermal characterization of soil-cement bricks using mining tailings

Soil-cement bricks are earth construction materials that have been gaining prominence due to their environmental advantages. The Brazilian Technical Standard NBR 8491 establishes physical and mechanical procedures to characterize these bricks. However, the thermal characterization is an important assessment, since it is related to the building’s thermal performance. The objective of this study is to thermally characterize a panel of soil-cement bricks produced with mining tailings. For such, its absorptance (α) was evaluated using the ALTA II spectrometer, and its thermal transmittance (U) and thermal resistance (RT) through the hot box method (ISO 9869). The results enabled the calculation of the thermal capacity (CT), thermal lag (φ) and solar factor (FSO) of the panel, which were compared to the Brazilian Technical Standards NBR 15575-4 and NBR 15220 for Bioclimatic Zone 8. As a result, the soil-cement body panel showed values of α = 0.71, U = 2.47 Wm-2K-1, CT = 273.4 kJm-2K-1, φ = 6.02 h and FSO = 6.81%, meeting the requirements established in the first standard, but failing to attend the second. To comply with the Brazilians specifications, it is suggested to paint bricks with lighter colors focusing on decreasing its absorptance value. Thus, soil-cement bricks may be an environmental alternative to dispose of the waste generated during the mining process, contributing to sustainability.

Study for the incorporation of wood ash in soil-cement brick

This study aimed to produce soil-cement brick with wood ash incorporation coming from the textile industry. The wood ash was a partial substitute for soil and cement in the manufacture of bricks. 7 formulations were made with different proportions of substitution: 10%, 20%, and 30%. It was noticed that the substitution of cement by wood ash in 10% resulted in brick with enhanced properties, showing a 20% increase for compressive strength and a reduction of 44% for mass loss, thus, with higher durability and a reduction of water absorption of 3%, when comparing to the reference brick (soil-cement). It was shown that the reuse of wood ash in the production of soil-cement bricks is a viable and sustainable option, as it is an alternative for the destination of the waste and a reduction in the consumption of Portland cement, which generates a high volume of carbon dioxide (CO2) during its production.

Soil-cement blocks: a sustainable alternative for the reuse of industrial solid waste

This study aimed to analyze potential industrial solid waste that can be added to soil-cement blocks. A narrative literature review was conducted in the Scopus academic database, using as the search criteria keywords related to the topic, such as soil-cement, building materials, soil-cement blocks, soil-cement bricks, physical and mechanical properties, solid waste, life cycle analysis, and civil construction. A variety of industrial solid waste that can be incorporated into soil-cement blocks was observed, such as waste rock, sludge from water treatment plants, wood sawdust, polyethylene terephthalate fibers (PET), vegetable fibers from loofah, hemp fibers, rice husks, brachiaria grass, poultry eggshells, sugar cane bagasse, wheat and barley straw, welding slag, foundry sand, waste from quartzite mining, construction, and demolition, mechanical turning, pulp industry grains, and steel mill co-products. Among the investigated wastes, those that improved the physical and mechanical properties of the soil-cement blocks were grains from the cellulose industry, rice husks, Brachiaria grass, steel by-products with granulated soil-cement blocks and blast furnace slag. The waste that produced no satisfactory results was sludge from a water treatment plant, sugarcane bagasse, and vegetable loofah. Through this research, it was possible to verify that the behavior of soil-cement blocks is influenced by several factors in their manufacture, mainly regarding the type and percentage of incorporated waste. However, it is important to be concerned with its application in waste blocks so as not to increase the environmental impacts in the long term.

Lignocellulosic materials as soil–cement brick reinforcement

The need for environmental preservation requires civil engineering to reach new concepts and technical solutions aiming at the sustainability of its activities and products. In this context, this study aimed to evaluate the effect of using different types and percentages of vegetable particles on the physical, mechanical, and thermal properties of soil-cement bricks. Bamboo, rice husk, and coffee husk particles at 1.5 and 3% percentages and a control treatment not using the particle were evaluated. The chemical properties, shrinkage, compaction, consistency limits, and grain size were characterized for the soil; and the anatomical, chemical, and physical properties for the lignocellulosic particles. The bricks were produced using an automatic press and characterized after the curing process for density, water absorption, porosity, loss of mass by immersion, compressive strength, durability, and thermal conductivity. The increase in the lignocellulosic waste percentage caused a mechanical strength decrease and bricks' porosity and water absorption increase. However, it caused a decrease in density and an enhancement in loss of mass and thermal insulation properties. The bricks produced with rice husk obtained the best results in terms of mechanical and thermal properties, and were still among the best treatments for physical properties, standing out among the lignocellulosic waste as an alternative raw material source for soil-cement brick production.

Soil-Cement Bricks Development Using Polymeric Waste.

This research aimed to evaluate the effect of adding different polymeric waste percentages and types on the physical, mechanical, thermal, and durability properties of soil-cement bricks. Tire and polyethylene terephthalate (PET) waste were evaluated at 1.5 and 3.0% (mass/mass). The soil was characterized in terms of shrinkage, compaction, consistency limits, particle size, and chemical analyses, whereas the waste particles were submitted to morphological characterization. The bricks were produced in an automatic press with a 90:10 (mass/mass) soil:cement ratio. The soil-cement bricks were characterized by density, moisture, water absorption, loss of mass by immersion, compressive strength, thermal conductivity, and microstructural analysis. PET waste stood out for its use as reinforcement in soil-cement bricks. The best performance was obtained for bricks reinforced with 1.5% PET, which showed a significant compressive strength improvement, meeting the marketing standards criteria, even after the durability test, as well as obtaining the lowest thermal conductivity values. The percentage increase from 1.5 to 3.0% fostered a significant water absorption and loss of mass increase, as well as a significant compressive strength reduction of the bricks.

Stress and strain analysis using Autodesk Inventor software in soil-cement brick

The computational analysis of materials is fundamental for a better understanding of their physical and mechanical properties, achieving more results in a shorter time. It is a cheaper, non-destructive, practical way, and easily adaptable to various types of models and physical influences. This study has the objective of ascertaining the stress and strain analysis in soil-cement brick through the Autodesk Inventor Professional software, which uses the finite element method. Three models of brick were made: two holes, monoblock, and groove, which are the most commonly used shapes. To the two holes model, the maximum first principal stress observed was 1.464x10-1 MPa and the third principal stress was 5.4x10-3 MPa, presenting an insignificant strain of 1.037x10-3 mm. In the monoblock model, the maximum first principal stress was 4.606x10-1 MPa, and the third principal stress was 1.19x10-2 MPa, presenting a strain of 1.611x10-3 mm. The groove model presented the maximum first principal stress at 3.263x10-1 MPa and for the third principal stress was 9.1x10-3 MPa, respectively, presenting a strain of 3.344x10-3 mm. It can also be observed that the models have stress concentrating regions in the sharp edges and notches of the part. Among the three models studied, the one that presented the most favorable stress-strain conditions was the two-hole model. Since it has a larger contact area, the load applied to it was better distributed, presenting higher resistance than the other models with a smaller contact area.

Soil characterisation used in ceramic industries and an analysis of its feasibility in ecological bricks

Abstract In this study, we aimed to characterise soils of three sedimentary deposits used as raw material sources for ceramic industries located in the Brazilian semi-arid region. The samples were collected in deposits located in the cities of Barra de São Miguel, Juazeirinho and Santa Cecília. They were named, prepared and submitted to tests to determine the mineralogical, chemical, physical and thermal characteristics using the XRD, EDX, Casagrande, granulometric analysis, TG and DTA. The soils presented compositions containing quartz, alumina and hematite, predominantly with about 90% of the total, with well-defined peaks in the diffractograms confirming the statement, and averages of plasticity and granulometric distribution that fit them as silt-clay. When heated to 1000 °C, fire losses were 17%, 16% and 29% for samples from Barra de São Miguel, Juazeirinho and Santa Cecília, respectively, which is due to the dehydration and burning of organic matter. Thus, they have met the requirements of the Brazilian standards that deal to produce sealing (with sintering) and soil-cement bricks (by pressing). The studied deposits offer satisfactory raw material for the ceramics industry and can provide soil for soil-cement brick (ecological bricks) production.