Fiber Cement Research Articles

Seaweed waste in eco-friendly construction materials: Valorization of Sargassum ash as a mineral addition in fiber cements

Many coastal regions have recently faced significant challenges due to the excessive accumulation of sargassum. This genus of brown marine algae generates greenhouse gases such as methane and carbon dioxide during decomposition, as well as toxic gases such as hydrogen sulfide and ammonia. The substantial influx of these algae on shores brings far-reaching impacts on the environment, climate, health, and the economy. One way to mitigate these impacts is by using this biomass for energy production and applying the resulting ash as an alternative material in the construction industry. As such, this study aims to analyze the feasibility of sargassum ash as a replacement for limestone in fiber cement. This not only offers an environmentally responsible solution for its disposal, but also adds economic value to a material commonly seen as a waste. Several analyses were conducted on the physical and mechanical properties of fiber cement with varying percentages of limestone replaced by sargassum ash (0, 25, 50, 75, and 100 %), as well as its durability and Life Cycle Assessment (LCA). The fiber cement with 100 % sargassum ash exhibited a 74 % increase in specific energy compared to the fiber cement without the ash after accelerated aging. This mix design also presented better environmental performance in 15 of the 18 impact categories. The results demonstrate that ash holds potential as an alternative material in fiber cement manufacturing.

Life Cycle Assessment of Construction Components of Schools in Southern Brazil

Introducing energy efficiency techniques in schools can significantly reduce energy consumption, as Brazil has a large public education system. The main objective of this work was to select the set of construction components with the lowest environmental impact for use in schools in Florianópolis, southern Brazil, through life cycle assessment (LCA). Two types of walls, four types of roofs, and two types of window frames were studied. Ceramic bricks measuring 14x9x19cm and 9x19x19cm were considered for the walls. Wood and aluminium were used for the window frames, with single glass panes on all windows. For the roofs, fibre cement tiles with a PVC ceiling, a drywall ceiling, and a concrete slab were considered, as well as ceramic tiles with a PVC ceiling. Computer simulations were conducted using the EnergyPlus program in order to determine the building’s energy consumption. SimaPro was used to run the LCA. The construction of the building and one year of its energy consumption were analysed to select the combination of components with the lowest impact on the building’s life cycle. Finally, the set consisting of 9x19x19cm ceramic brick walls, wooden frames, and roof with fibre cement tiles and PVC ceiling presented the lowest environmental impact. Keywords: Life Cycle Assessment; public schools; computer simulation; buildings; EnergyPlus; SimaPro

Effectiveness of Cool and Green Roofs Inside and Outside Buildings in the Brazilian Context

Several studies have assessed the thermal performance of green and cool roofs. However, few have comprehensively addressed Brazilian buildings and climates, considering indoor and outdoor environments. Considering three Brazilian cities, this study aims to assess the performance of green and cool roofs compared with traditional fibre cement roofs in a typical multifamily residential building. Energy consumption, thermal comfort, and outside surface temperature were assessed using computer simulation. The results show that the cool roofs performed better in cities with warmer climates (e.g., Cfa and Aw), reducing electricity consumption by up to 24.8% compared with traditional roofs. Green roofs are better suited for colder climates (e.g., Cfb), with up to 28.2% energy savings. Green roofs provided the highest percentage of thermal comfort hours in all climates. Cool and green roofs provided hourly reductions in outside roof surface temperature of up to 16.5 °C and 28.4 °C, respectively, compared with the traditional roof. This work reinforces that the choice between these two roof types for each city depends on the parameter used for comparison. Based on the relevant information applied to Brazilian buildings and representative climates presented, this work provided recommendations for urban planning policies and building regulations in Brazil.

Mechanical performance study of PVA fiber-reinforced seawater and sea sand cement-based composite materials

Due to the swift progress in the construction sector, there is a global concern about the potential scarcity of river sand and freshwater resources. The development of new construction materials is considered an inevitable trend for industry growth. PVA fibers, known for their strong corrosion resistance, cost-effectiveness, and high toughness, have the potential to enhance the corrosion resistance and seismic performance of structures in marine environments. However, their mechanical properties and durability in the seawater and sea sand environment are not well understood. Therefore, the investigation of the impact of seawater and sea sand on the mechanical properties and durability of PVA fiber-reinforced cement composites is considered crucial. A mechanical performance analysis of PVA fiber-reinforced seawater and sea sand fiber cement composites was conducted in this study. PVA fiber volume fractions of 0%, 0.75%, and 1.5%, cement composite matrix strength grades of C30 and C50, and curing periods of 28 days, 90 days, and 180 days were examined, investigating their influence on the bending toughness of PVA fiber-reinforced seawater and sea sand cement composites. Specific conclusions include the addition of fibers increased the peak bending load, had a less corrosive effect in seawater, and improved the flexural toughness of the material. The most significant improvement was observed at 1.5% fiber content, where the load-deflection curve was fuller and the energy absorption capacity of the material increased by 33–109%, maintaining good bending toughness. Furthermore, higher fiber contents are required for high-strength cementitious composites to improve flexural toughness and durability. The formulation of calculation formulas for predicting bending strength and corresponding deflection, which fit well with the experimental results; and the development of a calculation model for the bending toughness index of PVA fiber-reinforced seawater and sea sand cement composites, providing an effective prediction of material bending toughness.

A feasibility study of oil palm empty fruit bunch pulp as a substitution for radiata pine pulp for autoclave fibre cement composite production

The main objective of this study was to investigate the feasibility of using unbleached pulp from oil palm empty fruit bunches, produced via the Ethanolamine pulping process, to replace Radiata Pine pulp in autoclave fibre cement composite (AFCC) manufacturing. The Ethanolamine pulping process was chosen for its silica retention capability on empty fruit bunch surfaces. The research involves three key phases: an initial characterization of RPP and EFBP properties, including kappa numbers and pulp aspect ratios; subsequent AFCC production with varying RPP content levels (0%–13%) and different cement-to-silica (C/S) ratios (0.2–1.0); and the introduction of EFBP as a partial or complete substitute for RPP at a fixed C/S ratio. Results reveal RPP excels in fibre quality attributes like length, coarseness, fineness, width, and wet/dry zero span, while EFBP offers advantages in fibre count and macro fibrillation index. X-ray diffraction confirms silica presence on EFBP. The highest modulus of rupture (MOR), at 15.5 MPa, is achieved with 9% RPP and a C/S ratio of 1.0. Subsequent analysis, with 1% EFBP interval substitutions to total 13% pulp content, yields the highest MOR values under dry (16.7 MPa) and wet (9.9 MPa) conditions using recipes with 6% RPP and 3% EFBP. XRD confirms the presence of silica on EFBP, forming a crystalline flake layer post-autoclaving. Thus, EFBP proves suitable as a partial AFCC substitute.

Impact of mineralization in Hevea brasiliensis fibers on the production of extruded fiber-cements with cellulosic micro/nanofibrils (MFC/NFC) and quartzite residues

New processes and applications for waste generated in forestry and mineral activities favor the circular economy and reduce pressure on conventional raw materials, thus promoting the sustainability of activities. This research aimed to apply quartzite powder to replace limestone and fibers and cellulosic micro/nanofibrils (MFC/NFC) from Hevea brasiliensis as reinforcement in extruded fiber-cement. To improve fiber/matrix compatibility, some fiber treatments with NaOH and Aℓ2(SO4)3 + C6H8O7 were also evaluated. The fiber cements were produced by an extrusion process using a formulation of 66.5 % of CPV-ARI Portland cement, 28.5 % of quartzite powder and 5 % of fiber reinforcement. The physical (apparent density, water absorption, and porosity), mechanical properties (modulus of rupture, modulus of elasticity, limit of proportionality, and toughness), thermal conductivity, and microstructural properties of the fiber-cements were evaluated after 28 days of curing. Treatments with 5 % fibers exhibited better mechanical performances. It was possible to improve the microstructure and physical-mechanical performance of the composites using small amounts of MFC/NFC (0.5 %). Quartzite positively affected the properties and provided thermal comfort (∼0.11 W/mK). Therefore, the materials showed promise for producing extruded fiber-cement composites.

Innovative utilization of agro-industrial by-products: Bamboo leaf ash as a pozzolanic material for extruded fiber cement composites

This study aims to promote the valorization of agro-industrial waste and sustainability in the construction industry by evaluating the potential of bamboo leaf ash (BLA) as a partial replacement for Portland cement in extruded fiber cement. Squeeze flow, physical, mechanical, and microstructural analyses (Scanning Electron Microscopy and X-ray microtomography) were conducted. The results showed that the incorporation of fibers and BLA leads to an increased water demand and, consequently, an increase in porosity and pore connectivity. However, the mix design with 10 % replacement exhibited improved mechanical behavior for modulus of rupture (10.2 %) and limit of proportionality (4.5 %), when compared to a formulation without BLA. For the other parameters, the mix design with 10 % BLA showed mechanical behavior with no statical difference to the mix design without ash. Thus, the use of BLA as a partial replacement for Portland cement represents an alternative with technical and environmental improvements for fiber cement.

Using shredded fibre cement recyclate to produce new innovative fibre cement boards

Abstract The study investigated the effect of the addition of crushed recyclate on the final properties of fibre cement boards. In some fibre cement board production technologies, waste in the form of solid trimmings accounts for up to 7% of total production, which is not an insignificant amount. The research aims to maximise the use of the waste generated and its effective reintegration into the production of new fibre cement boards. In the experimental work, shredded recyclate was used in varying quantities to replace expanded perlite. The results obtained show that the reuse of shredded recyclate has a minimal impact on the observed physical and mechanical properties. A similar trend was found when evaluating the durability tests. The proposed solution for the reuse of recyclate can be considered successful both in terms of production technology and the properties of the fibre cement boards achieved.

Effect of Adding Oil Palm (Elaeis guineensis Jacq.) Mesocarp Fibers to Cement Composites

The construction industry's ongoing pursuit of eco-friendly materials has led to extensive research into fiber cement composites (FCC), particularly those utilizing natural fibers such as oil palm (Elaeis guineensis Jacq.) mesocarp fiber (OPMF) from Peru. This study examined the physical, mechanical, and chemical effects of adding different proportions of OPMF (0, 3, 6, and 9%) in manufacturing FCCs. This addition resulted in reduced values regarding density, porosity, and modulus of rupture, as well as in increased moisture content and thickness reduction. The FCC containing 3% OPMF exhibited the most favorable performance thanks to its higher density and its lower water absorption and porosity when compared to the control board (0%-OPMF). Micro-images revealed minor microcracks and interfacial gaps, indicative of debonding, which compromises the properties of the FCC. Furthermore, an infrared spectrum analysis demonstrated an increase in hydroxyl group vibrations with an increased fiber proportion.

Structural strength characteristics of fiber cement soil in road pavement of timber roads in the Sverdlovsk region

Structural strength characteristics of fiber cement soil in road pavement of timber roads in the Sverdlovsk region

Contemporary Concepts of Adhesive Cementation of Glass-Fiber Posts: A Narrative Review.

(1) Background: Cementation of glass fiber posts to root canals has been associated with various failures, especially debonding. This narrative review aims to present the contemporary concepts concerning the adhesive cementation of glass fiber post and to discuss the optimal management of these factors. (2) Methods: Electronic search was performed in MEDLINE/Pub Med and Google Scholar using selected keywords examining the parameters post length, surface treatment of glass fiber posts, post space preparation and dentin pretreatment, resin cement selection, adhesive systems and hybrid layer formation, and clinical techniques. (3) Results: The search led to the selection of 44 articles. Epoxy resin-based endodontic sealers are recommended and the use of temporary cement in the root canal should be avoided. The minimum length of a glass fiber post adhesively cemented to a root canal is 5 mm. Irrigating the root canals with chlorhexidine, MTAD, or EDTA (alone or in combination with NaOCl) after post space preparation seems to enhance the bond strength. Silane application on the surface of the post seems to be beneficial. Concerning resin cements and adhesive systems, the results were rather inconclusive. Finally, resin cement should be applied inside the root canal with an elongation tip and photoactivation should be delayed. (4) Conclusions: Contemporary concepts of adhesive cementation of glass fiber posts can indeed improve the bond between glass fiber posts, resin cement, and root canal dentin, however, evidence coming from long-term randomized prospective clinical trials is needed in order to obtain safer conclusions.

Assessment of carbonation as a complementary strategy to increase the durability of Magnesium Oxysulfate (MOS)-based fiber cement boards

Magnesium oxysulfate (MOS)-based fiber cement boards reinforced with lignocellulosic fibers were manufactured using the Hatschek process and cured for 24, 48, and 72 hours before curing in a CO2-rich atmosphere. The boards were rehydrated before the accelerated carbonation process to evaluate changes in carbonation after water addition to the system. The materials showed property changes after accelerated carbonation, which was responsible for an increase of approximately 15 % in the MOR values of the carbonated boards after 48 hours. In contrast, pre-rehydration of the boards increased the Modulus of Rupture (MOR), Limit of Proportionality (LOP), and Modulus of Elasticity (MOE)values of the carbonated materials and favored the production of cementitious composites with specific energy values close to 4.4 kJ/m2. The quantification of mineralized CO2 showed that the rehydrated and carbonated boards after 48 hours presented the highest SCO2(effective) values, which is related to the densification and consequent decrease in voids in the carbonated materials under these conditions. Accelerated aging showed that the carbonated boards had a lower loss of mechanical properties, demonstrating that accelerated carbonation, in addition to increasing mechanical properties, emerges as an alternative to increasing the long-term durability of MOS-based fiber cement boards.

INFLUENCE OF CEMENT AND COIR FIBER ON THE MECHANICAL PROPERTIES OF RAMMED EARTH

Rammed earth, a construction is widely used globally due to its ease of availability of materials and mechanical performance. Stabilization is necessary in rammed earth construction to enhance the binding of the soil particles which in turn increases the mechanical and durability properties of rammed earth. The purpose of this research is to determine the optimum percentage of chemically treated Coir fiber dust and cement for rammed earth. Fibers and cement can be easily integrated into the soil mixture, increasing the wall's strength and durability. Compressive, flexural, and tensile strength tests were performed on the samples, and failure patterns were studied. Cement is varied in percentages of 6%, 9% and 12% and coir fiber dust (0.1, 0.2, 0.3, and 0.4 percent by weight of soil) were added as stabilizer and reinforcement. To assess the optimum strength and durability, it is recommended to utilize 0.2 percent fiber content Coir fiber dust, along with 9 percent cement by weight of soil. It is observed that with the cement and fiber dust incorporation there has been increase in the mechanical properties of rammed earth. Keywords- Cement Stabilized Rammed Earth (CSRE), Coir Fiber Dust, wet compressive strength, flexural strength.

Valorization of magnesium slag and CO2 towards a low carbon fiber reinforced cement board

Pyrometallurgical extraction of magnesium from dolomite ores results in a large amount of magnesium slag discharge and CO2 emission, posing severe environmental hazards. This study introduces a new approach for the simultaneous upcycling of magnesium slag and CO2 by taking advantage of the high carbonation reactivity of magnesium slag. A CO2-solidified magnesium slag-based fiber cement board with high-strength and high-toughness (CHFCB) is developed, using magnesium slag as the binder, CO2 as the activator, and a mix of pulp and PAN fibers as the reinforcement. The optimal CHFCB preparation process was explored by adjusting the fiber ratio, molding pressure, and CO2 curing system, and the mechanisms underlying its strength and toughness were analyzed. The results indicated that with the optimal preparation, CHFCB exhibited a water-saturated flexural strength of nearly 20 MPa and a drying flexural strength of over 25 MPa. The ultimate deflection could be increased by up to 80 % or more during the bending deformation of CHFCB, while the tensile strain could be improved by over 50 % in the tensile fracture process of CHFCB. After 100 freeze-thaw cycles, the water-saturated flexural strength ratio of CHFCB reached 97.2 %, showing excellent durability. The microanalysis revealed that the dense stacking of calcite-type calcium carbonate and the presence of PAN fibers contributed to the high-strength and high-toughness of CHFCB. Additionally, the environmental and economic benefits of CHFCB were assessed, affirming its role as a sustainable building material that promotes energy efficiency and a green economy.

Eco-roofs: influence of shape and material variations on surface temperature, rainwater volume and quality

ABSTRACT To mitigate climate change it’s of utmost importance to generate, develop, and improve green technologies. Technologies that link civil construction, architecture, and sustainability are largely necessary for this goal. Green roofs constitute technologies with high potential to contribute to the increase of the resilience of cities in the face of climate change. Since this technology is versatile and still requires many studies, we tested three different types of situations and considered three subprojects: 1 – how the arrangement of fiber cement coverings can affect runoff control and water quality, the differences between the temperature in three types of tiles and the spontaneous growth in each of them; 2 – how nasturtiums, once used as cover, influence water quality and thermal comfort; 3 – the viability of seed germination on roofs with substrate. In subproject 1 it was concluded that spontaneous growth did not occur during the experiment period and that the arrangement of the tiles influences the ability to reduce surface runoff. In 2 we observed that the plants require frequent watering, and that nasturtium does not develop abundantly in thin layers of substrate but contributes to thermal comfort inside buildings. There was an average reduction of 6.8% in the temperature values on the substrates in Subproject 2 due to the presence of vegetation, while for the surface temperature, the values were, on average, 11.7% lower for the prototypes with vegetation cover. In subproject 3 we concluded that seed sowing directly on substrate roofs does not present satisfactory results for developing green roofs.

Comparative performance of M-S-H cement vs. portland cement in fiber cement incorporating bamboo leaf ash and cellulosic fibers

This study evaluates the potential of alternative materials such as Hydrated Magnesium Silicate (M-S-H) cement, bamboo leaf ash (BLAsh), and cellulose fibers to enhance the sustainability and performance of fiber cement composites. Innovative in its approach, the research incorporates BLAsh and cellulose fibers into M-S-H and Portland cement (OPC) matrices using an innovative production process: extrusion. For the characterization of different formulations, a comparative analysis was conducted on samples with M-S-H and Portland cement matrices, with BLAsh replacing limestone and the addition of unbleached pine cellulose fibers. The analysis covered the physical, mechanical, and microstructural properties of the composites. After a 7-day curing period, they were subjected to 200 cycles of accelerated aging to evaluate durability. Microstructural analysis revealed the binding potential of the M-S-H matrix used in this study due to the pronounced formation of M-S-H gel and reduced content of Mg(OH)2 over time. The formation of C–S–H and M-S-H gel as the main phase for each type of cement is even more evident in samples incorporating BLAsh, indicating the interaction between both types of matrices and bamboo leaf ash. The study demonstrated that adding BLAsh to the composites significantly improved the modulus of rupture of the OPC samples (approximately 32 %), while considerably reducing water absorption for the M-S-H samples (around 50 %). Aging affected water absorption differently in OPC and M-S-H samples, with OPC showing decreased absorption and the M-S-H showing increased absorption post-aging. The study proved both types of cement suitable for producing composites that meet NBR 15498 standards for external applications. This demonstrates the technical feasibility of these compounds for their production by 3D printing.

Innovative MOS-based fiber cement boards: Effect of kraft pulp mills waste and curing by accelerated carbonation

The increasing global waste generated by industrial activities poses significant environmental challenges. Eco-waste management emerges as an economically viable solution for converting, valorizing, and repurposing these byproducts, aligning with circular economy principles, and aiming to reduce greenhouse gas emissions. Construction, known for its unsustainability due to high energy consumption, non-renewable resource utilization, waste generation, and greenhouse gas emissions, particularly from cement production, has led to the exploration of alternative materials. Magnesium oxide (MgO)-based cement, an alternative to Ordinary Portland Cement (OPC), has gained attention, leveraging Brazil's prominence as a major magnesite producer. This study explores the valorization of waste from kraft pulp mills of the paper industry, specifically lime sludge (LS) and lime slaker grits (grits), to produce magnesium oxysulfate (MOS)-based fiber cement boards. The effect of accelerated carbonation on cementitious composites produced with formulations containing grits and LS was investigated. Replacing 25% of the limestone with grits showed no noticeable differences in the properties of the boards, and MOR values close to 11.17 MPa were obtained. However, the physical-mechanical performance showed a decrease with the use of LS and higher concentrations of grits, associated with Na2SO4.XH2O formation in the system and ITZ structure formed around the aggregated particle, respectively. Carbonation in a saturated atmosphere led to the carbonation of the 5–1–7 phase, which was related to the decrease in mechanical strength of the boards after the curing process. The thermal decomposition of the Hydrated Magnesium Carbonates (HMCs) formed during accelerated carbonation corroborated with the changes in the physical properties of the composites, demonstrating that the carbonation products are formed within the voids and pores of the material and contribute to the reduction in water absorption of the boards.

Embodied Energy Coefficient Quantification and Implementation for an Energy-Conservative House in Thailand

Embodied Energy Coefficient Quantification and Implementation for an Energy-Conservative House in Thailand

Experimental study on dynamic and static mechanical properties of polyvinyl alcohol fiber cement soil under salt freezing cycle

A universal testing machine and a 50 mm split Hopkinson pressure bar (SHPB) were used to conduct salt erosion and freeze-thaw (F-T) cycle coupling tests on cement soil specimens with 0.5% polyvinyl alcohol (PVA) fiber and without fiber in order to study the effects of salt solution and F-T cycles on the dynamic and static mechanical properties of cement soil. In four distinct solution settings (clear water, 9 g/L sodium sulphate solution, 9 g/L sodium chloride solution, and 9 g/L sodium sulphate and sodium chloride mixed solution). After F-T cycles, the cement soil specimens underwent the unconfined compressive strength (UCS) test, SHPB test, and SEM test. The findings indicate that as the number of F-T cycles increases, the dynamic and static mechanical properties of cement soil specimens decrease, and the rate of decline is rapid followed by slow. After five F-T cycles, the combined solution's unconfined compressive strength dropped to 15.91% (without fiber) and 29.41% (with fiber), respectively. After five F-T cycles, the dynamic compressive strength in sodium sulphate solution fell by 95.17% (without fiber) and 93.86% (with fiber). Fibers help to some degree by preventing salt erosion and F-T cycles. With more F-T cycles, the absorbed energy declines exponentially, and the order of the solutions' effects on the absorbed energy is: mixed sodium chloride and sodium sulphate solution > sodium chloride solution > sodium sulphate solution > clear water.

Effect of Hybridization of Carbon Fibers on Mechanical Properties of Cellulose Fiber–Cement Composites: A Response Surface Methodology Study

Fiber-reinforced cement composites, particularly those incorporating natural fibers like cellulose, have gained attention for their potential towards more sustainable construction. However, natural fibers present inherent deficiencies in mechanical properties and can benefit from hybridization with carbon fibers. This study focuses on the incorporation of cellulose and carbon fibers, in varying contents, into fibrocement composites, employing a Response Surface Methodology (RSM) to optimize the material characteristics. The methodology involves testing, encompassing flexural tensile, compression, and fracture toughness tests. The results indicate an increasing trend in flexural strength for higher carbon fiber content, peaking near 5%. A plateau in flexural strength is observed between 1.2% and 3.6% carbon fiber content, suggesting a range where mechanical properties stabilize. Compressive strength shows a plateau between 1.2 and 3.6% and reaches its highest value (≈33 MPa) at a carbon fiber content greater than 4.8%, and fracture toughness above 320 MPa·m1/2 is achieved with carbon fiber content above 3.6%. This study offers insights into optimizing the synergistic effects of cellulose and carbon fibers in fibrocement composites.