Minimum Strength Requirements Research Articles

Evaluation of Clayey Raw Materials and Ceramic Masses from Ceramic Building Material Companies Located in Northeastern Brazil

The challenge of improving the quality of ceramic products is faced worldwide, especially in areas where artisanal production is common and the need for in-depth knowledge about raw materials, together with inefficient production processes, limits the advancement of the ceramic industry. Scientifically, detailed investigation of ceramic masses’ physical, chemical and mechanical properties can provide essential insights to optimize production, contribute to developing more advanced and sustainable techniques, and increase competitiveness. This study evaluated raw clay materials and ceramic masses obtained from northeastern Brazilian, focusing on their chemical composition, mineralogical phases, thermal behavior, and particle size distribution. Rectangular samples (80 mm × 20 mm × 7 mm) prepared using uniaxial pressing (25 MPa by 30 s) were fired at different temperatures (950 and 1050 °C) and linear shrinkage, flexural strength, water absorption, and apparent porosity measurements were taken. The results showed that the companies still need to improve the production process to meet the minimum strength requirement of 1.5 MPa according to the Brazilian standard NBR 15270.

Analysis of the Mechanical Properties of Structural Ceramics Made from Aggregate Washing Sludge and Manganese Mining Waste.

The construction sector is presently among the most resource-intensive industries, driving a substantial body of research dedicated to the development of more sustainable materials to address these demands. A particularly promising approach within the framework of the circular economy is the repurposing of waste as a principal raw material for the creation of new construction products. Within this context, the primary aim of this study is to engineer ceramic materials for brick production using 100% waste-derived inputs, specifically aggregate washing sludge and manganese mining by-products. To evaluate the potential of these sustainable ceramic materials, an extensive investigation was conducted, encompassing both physical and mechanical testing, as well as a thorough characterisation of the waste inputs. For this purpose, a series of ceramic specimens were fabricated with varying proportions of mining residues and aggregate washing sludge, adhering to the conventional protocols employed in the manufacture of ceramic bricks. The results demonstrate that these sustainable ceramics exhibit a linear shrinkage reduction of up to 5% compared to traditional clay-based ceramics. Furthermore, they show water absorption levels-whether via capillarity, cold water, or hot water absorption-that are up to twice those observed in conventional clay ceramics, while maintaining comparable density values. This increased absorption, however, correlates with a reduction in mechanical strength at higher concentrations of manganese waste, yet the material continues to meet the minimum strength requirements as specified by industry standards for such products. In conclusion, this research introduces a novel, sustainable ceramic material that not only reduces economic and environmental costs but also adheres to the required performance criteria for construction applications.

Database of tall pre-Northridge steel moment frames for earthquake performance evaluations

This article describes a detailed database of tall steel moment frame buildings that are representative of the construction practices in San Francisco prior to the 1994 Northridge earthquake. The database contains design details that affect the structural performance of steel moment frames, including frame geometry, member cross-section sizes, and gravity system characteristics. This database also captures irregularities that might impact seismic response, such as podiums, setbacks, mass concentrations (mechanical, electrical, and plumbing (MEP) floors), interrupted column lines, and atriums. The database includes information on 89 moment frame buildings, 14 of which were built before 1960 and are constructed with riveted connections, while the remaining 75 have welded flange connections like those that suffered brittle fracture during the 1994 Northridge earthquake. The buildings are further distinguished between space frame, perimeter frame, and partial space frame systems. For about half (41/89) of the buildings in the database, section sizes of representative structural members were collected, which enabled the evaluation of the seismic design, elastic, and inelastic response using computational workflows. The design diagnostics indicate that most of the buildings meet the minimum seismic strength and strong-column weak-beam requirements of modern building codes, even though they were not necessarily designed with this intent. On the contrary, about one-third of the buildings do not meet the seismic design drift limit of current codes, and about half of them have weak beam-column panel zones. This database, associated structural analysis models, and processing scripts are published at DesignSafe https://doi.org/10.17603/ds2-wjad-r340 to facilitate collaboration and continued development of open-source data for high-resolution simulations to inform risk mitigation strategies on a regional scale.

Strength and Erosion Resistance of Spinifex Fibre Reinforced Mudbrick

This study assesses the usability of natural materials available in Australia’s remote communities for making fibre-reinforced mudbricks. The present construction cost for housing in remote areas is too high to maintain the level of housing required for the remote Australian population. As this includes mostly First Nations communities, more culturally appropriate housing materials and construction methods are being considered. This study looks at mudbricks made from laterite soil reinforced by spinifex fibre, both available in abundance in remote communities. Hence, this material is more acceptable to communities as it is more sustainable, and the construction methods are more suited for First Nations engagement. Various mixes were tested for compressive strength and erosion resistance. Results suggest that spinifex can significantly improve compressive strength and reduce erosion effects; however, spinifex showed adverse effects at the early stage of the spray test. The results satisfy the minimum strength and erosion resistance requirements for construction and suggest that spinifex-reinforced mudbricks could potentially be considered as an alternative material in remote housing.

Evaluation of Early-Age Compressive Strength in Winter Prefabrication: A Comparative Study

In the field of prefabrication, the timely demolding of concrete elements is crucial to prevent structural failures during panel lifting. This study investigates the early-age compressive strength of different concrete mixtures by simulating various prefabrication plant scenarios. Special attention is given to winter conditions, where concrete hydration tends to be slower, potentially compromising the minimum compressive strength requirement of 10 MPa. The first scenario (reference), set at an ambient temperature of 20 °C with raw materials at room temperature, establishes the baseline for comparison. Two alternative dispositions are explored: Scenario 2, with an external temperature of 8 °C and the water for mixing at 35 °C, and Scenario 3, with the same external temperature but utilizing a heating hood to maintain the concrete at 35 °C. The experimental results shed light on the effectiveness of different strategies in achieving the desired early-age compressive strength under winter conditions. The use of warm mixing water and heating hoods are evaluated as potential measures to counteract the hydration slowdown. The findings contribute valuable insights for optimizing prefabrication processes in cold weather, ensuring the structural integrity of precast concrete elements.

Advancing Sustainable Construction Materials: Wood, Rubber, and Cenospheres Geopolymer Masonry Units Development

As the environmental impact of modern society continues to escalate, the construction industry actively pursues environmentally friendly materials to revolutionize its practices. Recycling, especially repurposing end-of-service materials and industrial wastes, emerges as a pivotal strategy offering a promising path towards sustainable construction. This study focuses on the innovative reuse of end-of-service wood, crumb rubber, and cenosphere with geopolymer binder to produce sustainable alternatives to masonry units. The study was conducted in two stages. In the first stage, cube samples were produced and tested to establish an optimal mix design. Results indicated that as the relative volume of waste increased, the compressive strength decreased. The compressive strength of the wood geopolymer composite decreased from 25 MPa to 4 MPa as the wood-to-binder ratio increased from 0.1 to 0.5. An increasing trend was observed for density with the increase of the rubber-to-wood ratio. The compressive strength also increased with the increase of the rubber-to-wood ratio for most of the investigated ranges. As fly ash is gradually replaced by cenospheres, a significant decrease in compressive strength was noted, about 70% and 80% for wood-to-binder (ratios of 0.2 and 0.3, respectively). In the second stage, three distinct types of masonry units were produced and tested based on the optimized mix design. The compressive strength results indicated promising performance, with wood-geopolymer masonry units exhibiting a strength of 8.39 MPa, wood-rubber-geopolymer masonry units achieving 8.32 MPa, and wood-cenosphere-geopolymer masonry units resulting in 7.33 MPa. While these values fell below the target 10 MPa, it is noteworthy that wood-geopolymer masonry units and wood-rubber-geopolymer masonry units met the minimum compressive strength requirements of some standards and demonstrated significantly better ductility compared to traditional masonry units. The results showcase significant promise in the viability and performance of these innovative masonry units.

Accelerated carbonation curing of concrete incorporating calcium carbide residue

The synergic effect of accelerated carbonation curing and cement replacement by calcium carbide residue (CCR) on the carbon sequestration potential and performance of concrete was examined. The concrete mixes included 0, 5, 10, and 20 % (by mass) CCR as partial cement replacement and were subjected to different initial air curing durations (0, 4, and 20 h) and subsequent carbonation curing durations (4 and 20 h). The performance was evaluated based on the CO2 uptake, 1-, 7-, and 28-day compressive strengths, and volume of permeable voids. Scanning electron microscopic (SEM) imaging was used to characterize the microstructure of the carbonated concrete. The environmental footprint of concrete produced herein was assessed. The experimental results showed that using CCR enhanced the CO2 uptake of concrete, with 5 and 10 % replacement levels providing superior outcomes in concrete subjected to 4- and 20-h carbonation curing. The compressive strength and a volume of permeable voids improved upon replacing cement with 5 % CCR. Such findings were validated by examining the void space in the SEM micrographs. Furthermore, prolonging the initial air curing and carbonation durations to 20 h each and incorporating 20 % CCR resulted in the highest CO2 uptake and lowest carbon footprint. Among the developed mixes, the most suitable was the mix subjected to 20 h of each initial air curing and carbonation curing with 20 % CCR replacement by mass. Nevertheless, all developed mixes satisfy the minimum strength requirement for concrete masonry unit applications.

Utilization of Quicklime and Limboto Lake Sediment as Basic Materials for Brick Walls

This study is based on knowing the compressive strength of bricks. The objectives that can be achieved are to analyze the characteristics of brick walls using lime, sedimentary soil and clay as well as conventional bricks and evaluate the comparative cost of making conventional bricks and lime-mixed bricks plus sedimentary soil. In this study, Data obtained from testing and analyzed quantitatively using appropriate statistical methods. This analysis will help in understanding the relationship between the composition of the mixture, the manufacturing process, and the characteristics of the resulting bricks. From the results of the analysis, the water absorption of bricks mixed with sedimentary materials, clay and lime. variation of sample 1, where the sample mixture (75% / 20% / 5%) water absorption is (29.72%) variation of sample 2, where the sample mixture (50% / 45% / 5%) water absorption is (9.45%) and Sample 3, (25% / 70% / 5%) water absorption is (9.22%). and clay bricks or without a mixture (100%) is (8.25%). This shows that the absorption capacity of mixed bricks of sediment, clay and lime materials which only have two variations 2 and 3. Meet the requirements of SNI 15-2094-2000 which requires a maximum water absorption capacity of 20% of bricks. While the average compressive strength comparison value of mixed bricks of sediment, clay and lime materials. sample variation 1, which sample mixture (75%/20%/5%) compressive strength value (13.6 kg/cm2) sample variation 2, (50%/45%/5%) which compressive strength value (19.8 kg/cm2) and sample 3, (25%/70%/5%) which compressive strength value (7.4 kg/cm2). and clay bricks without a mixture (100%) namely (36.4 kg/cm2). The compressive strength value of mixed bricks of sediment, clay and lime materials. Does not meet the minimum compressive strength requirements for building earthquake-safe houses (≥30).

Feasibility of recycled concrete aggregate stabilized with one-part geopolymers as semi-rigid inclusion columns

Recycled concrete aggregate (RCA) is a voluminous solid waste material derived from the construction sector and is typically stockpiled in landfills. In recent years, the ground improvement industry has grappled with challenges stemming from the depletion of natural quarry materials, resulting in a skyrocketing of their prices and increased project costs. This research investigated the feasibility of using RCA stabilized by one-part geopolymers to produce an innovative semi-rigid inclusion column system for ground improvement of soft soils. Na2SiO3-anhydrous was used as a sole solid activator for the activation of fly ash (FA), slag (S) or a binary precursor (FA+S) in the stabilization of RCA. The unconfined compressive strength (UCS) and microstructure of the stabilized mixtures have been examined with respect to different binder formulations and curing conditions. The permanent deformation characteristics of mixtures under cyclic loading were evaluated through repeated load triaxial (RLT) tests to replicate the moving wheel loads imposed on the semi-rigid inclusion columns. In addition, the cost and environmental impacts of the optimum mixtures suggested in this research were studied. The test results indicated that stabilizing RCA with as low as 5% one-part alkali-activated FA, S or (FA+S) met the minimum strength requirement (1.034 MPa) for ground improvement work. Compared with standalone FA and S geopolymer stabilized RCA mixtures, (FA+S) geopolymer stabilized RCA mixtures were identified as preferred industrial formulations due to their prolonged setting time for ease of mixing and handling when used in stone column applications. It was found that curing temperature and duration played a pivotal role in the strength gain of the mixtures. The RLT test results demonstrated that implementing the optimum RCA + 5%(FA+S) mixture as identified in this study for semi-rigid inclusion columns, led to a reduction in permanent strain values by approximately 90% compared to conventional unbound stone columns. The comparison between the optimum mixture highlighted in this study with other stabilization methods showed that the semi-rigid inclusion columns had great potential to enable large-scale production, cost and emission reduction in future ground improvement projects.

Mechanical properties of on-site manufactured stabilised compressed earth blocks: an experimental investigation and proposed models

ABSTRACT The interest in earth construction is growing increasingly as society becomes more aware of the importance of sustainable building. A considerable number of investigations have been devoted to studying the mechanical properties of compressed earth blocks (CEBs). However, most of these studies were conducted in laboratory settings. Little focus has been directed at studying the performance of CEBs that use on-site soil and other local materials to construct small-scale housing at the same location. A total of 120 CEBs were manufactured on-site from four block mixes: coarse soil with and without Phragmites Australis (Phragmites) and fine soil with and without Phragmites. By comparing the results achieved with minimum strength requirements from different building codes, the dry compressive strengths of all four block mixes were deemed adequate for single-storey structures. The addition of Phragmites caused a slight increase in the compressive strength and a slight decrease in the flexural strength of the CEBs. A formula to estimate the flexural strength of the blocks given the compressive strength is proposed based on a database of test results from the literature and this investigation’s results. CEBs can create a sustainable building solution, especially in remote areas and Indigenous communities with limited access to conventional building materials.

Analyzing the Mechanical, Durability, and Microstructural Impact of Partial Cement Replacement with Pumice Powder and Bamboo Leaf Ash in Concrete

This study explores the physiomechanical and durability properties of C-25 concrete by partially replacing cement with blends of pumice powder (PP) and bamboo leaf ash (BLA). The combined amount of major oxides SiO2, Al2O3, and Fe2O3 in PP is 84.59%, while in BLA, it is 74.4%, classifying PP and BLA as class N and F pozzolans. Subsequently, the study examines the impact of different cement replacement percentages, emphasizing 5%, 10%, 15%, and 20% on C-25 with varying mixes of concrete: Mix-1 (100, 0, and 0), Mix-2 (90, 5, and 5), Mix-3 (85, 10, and 5), Mix-4 (85, 5, and 10), and Mix-5 (80, 10, and 10) which correspond to the proportions of OPC, VPP, and BLA used in each mix respectively and by using 1 : 2.34 : 2.68 (cement : sand : aggregate) with the water/cement ratio (w/c) of 0.491. The study’s findings indicate that as the proportion of PP and BLA increases in concrete, the workability of the mixture decreases. Moreover, on the 28th day, Mix-2 with (35.84 MPa) and Mix-3 with (33.55 MPa) met the desired mean compressive strength (33.5 MPa) required for C-25 concrete per the ACI standards. Additionally, the flexural strength of concrete produced with partial replacement of Mix-2 with a flexural strength of 3.86 MPa fulfills the minimum strength requirement of 3.5 MPa specified by the C-25 ACI standards. The PP and BLA blended concrete had lower water absorption than the control mix in Mix-2. It also improved resistance to sulfuric acid attack, and Mix-3 had the least strength reduction of 9.59%. In contrast, the control mix has a 33.34% strength reduction.

Utilization of geopolymer in wood wool insulation boards: Design optimization, development and performance characteristics

This study investigates the substitution of ordinary Portland cement (OPC) with geopolymer in the production of wood wool geopolymer boards (WWGB), offering insights into manufacturing methods, design parameters, and performance characteristics. The composite formulation involves fibre pre-treatment, adjustment of precursor components, and control of activator compositions. The optimized formulation results in a lightweight composite with a density of 392 kg m−3 and porosity of 76 %, meeting prescribed minimum compressive (20 kPa) and bending strength (1700 kPa) requirements. The inclusion of natural fibres influences the optimal Na2O concentration and modulus for strength, with treated fibres recommended for higher modulus applications and improved strengths. Furthermore, it exhibits low thermal conductivity at 77 mW m−1 K−1, minimal moisture sorption, and low vapour resistance, offering a sustainable alternative in the field of insulation materials.

Identifying optimal combinations of synchronous condensers for minimum grid strength compliance

This paper proposes a method for the automatic optimization of the size and location of synchronous condensers (SCs) to meet a minimum grid strength requirement that enables the high penetration of inverter-based resources (IBRs) in a weak network. The grid strength is quantified by the effective short-circuit ratio (ESCR), which is an heuristic index that accounts for the voltage interactions between IBRs. The basin hopping algorithm (BHA) is used in combination with the Nelder–Mead algorithm to minimize the total additional short-circuit contribution from the SCs, subject to a minimum ESCR constraint. It is shown that this optimization problem has several solutions with the minimum values of the objective function lying within a narrow range but different allocation of the SCs’ capacities to the candidate buses. Therefore, the BHA is iteratively applied to identify the area of the search space in which the optimum solutions are located, and additional criteria are proposed to rank the solutions based on cost and reliability attributes. The effectiveness of the proposed approach is shown using a modified 39-bus New England benchmark system in which conventional synchronous generators were replaced by IBRs, thus leading to weak network conditions.

Dolomitic Limestone Powder: Cement Substitute in the Production of Structural Concrete Paving Blocks

Manufacturers are replacing or combining cement with mineral additives such as slags, natural pozzolans, sand, diatomaceous earth and limestone to reduce carbon dioxide emissions and energy usage. Due to its high magnesium content, dolomitic limestone has long been utilized in concrete production to reduce costs and environmental risks associated with making cement. This study aimed to produce a reliable and appropriate concrete mixture for concrete paving blocks using dolomitic limestone powder that passed the no. 24 sieve as cement replacement at replacement levels of 0 (control mix), 8, 12, 16, 20, 24, 28 and 32%, satisfying the minimum compressive strength requirement for structural concrete of 20.7 MPa (3,000 psi). The ASTM E877-13 was used to sample the dolomitic limestone, and the 1:1.5:3 concrete class combination was utilized to proportion the quantities of cement, sand and aggregates (3/8”). After 28 days, the specimens were cured and the compressive strength, through the varying water-cement ratios in the concrete mixture, was determined. Results showed that dolomitic limestone powder can substitute cement by 16% by weight, using a concrete mix of 523-g cement, 936-g sand, 1,868-g gravel, 100-g dolomitic limestone powder, and 166-g water with a water-cement ratio of 0.318, exceeding the minimum necessary compressive strength of concrete of 20.7 MPa by 24.9% or 5.16 MPa. Therefore, it is advised to utilize this proven concrete mixture as a basis for a potential business venture in the production of concrete paving blocks for structural concrete applications such as walkways, sidewalks, parking lots and commercial areas, as well as in places where loads are very high, like airports, courtyards, docks and freight yards.

Synergistic impacts of high-volume fly ash and sugarcane bagasse ash on performance of cementitious composites reinforced with polyvinyl alcohol fibers

Disposal of waste materials in fertile land is one of the pressing environmental issues, disrupting human, animal, and plant life. This has led the researchers to process and use such waste in ecofriendly construction products like mortar and concrete. Their usage as supplementary cementitious materials (SCMs) would reduce the quantity of cement used in the manufacturing of cement-based materials, lowering CO2 emissions related with cement production. In this regard, this study examines the feasibility of replacing high-volume of ordinary Portland cement (OPC) in engineered cementitious composites (ECC) with two widely used waste materials, sugarcane bagasse ash (SCBA) and fly ash (FA) as SCMs. Five different mixes were produced, each containing a fixed amount of polyvinyl alcohol (PVA) fibers at a dosage of 1.5 % by volume of the mix and a constant cement content of 50 % by weight of the binder (OPC + FA + SCBA). However, FA was replaced with SCBA in these mixes up to 100 % by the combined weight of the waste materials (FA + SCBA) in increments of 25 % (i.e., FA100-SCBA0, FA75-SCBA25, FA50-SCBA50, FA25-SCBA75, and FA0-SCBA100). The results showed that the compressive strength and flexural strength of the composites with the increasing levels of SCBA were reduced. Interestingly, the 28-day compressive strength of composite incorporating 50 % FA and 50 % SCBA was still as high as 25.58 MPa, which satisfied the minimum compressive strength requirement of ASTM C270, making the newly produced ECC suitable for use in normal construction works and repairs. The same optimum mix (FA50-SCBA50) produced an average density of 1867.96 kg/m3 as a result of substituting a significant amount of binder with SCBA, demonstrating that it has evolved into a lightweight engineered cementitious composite. Furthermore, the ultrasonic pulse velocity of the mixes decreased whereas water absorption increased as the proportion of SCBA to FA increased. According to microstructural analysis, unreacted SCBA particles were mostly responsible for the detrimental effects of rising SCBA levels on properties of ECC. Based on the aforementioned results, this research concludes that sugarcane bagasse ash, when combined with fly ash, could be a viable alternative for replacing regular cement up to 50 % by weight in the production of cost-effective and environmentally friendly cementitious composites.

Innovative sustainable ceramic Bricks: Exploring the synergy of natural zeolite tuff and aluminum dross

This study explored the efficient utilization of natural zeolite tuff and aluminum dross for making porous ceramic bricks, aiming to address environmental damage from waste disposal. Different compositions of these materials were used to create six batches of bricks, followed by heat treatment at varying temperatures (950–1150 °C). The raw materials and the sintered samples were analyzed using various characterization techniques. The results showed that bricks incorporating 30 % aluminum dross and sintered at 1150 °C had the lowest thermal conductivity of 0.3 W/m·K. On the other hand, bricks containing 20 % aluminum dross and sintered at the same temperature exhibited the highest compressive strength (58 MPa), a bulk density of 1.9 g/cm3, and a water absorption of approximately 13 %. All samples exceeded the minimum compressive strength requirements. This study demonstrates the feasibility of using natural zeolite tuff and aluminum dross to develop composite bricks, providing an effective waste disposal solution for sustainable development and reduced environmental pollution.

Manufacturing of Clay Bricks Using Hybrid Waste Marble Powder and Sugarcane Bagasse Ash: A Sustainable Building Unit

In masonry construction, the most commonly used building unit all over the world is the burnt clay brick. Adding waste materials in certain percentages to these bricks helps in eliminating the environmental burden occurring in the form of excessive waste accumulation on open land sites, leading to sustainable and economical construction. This research program aimed to examine the feasibility of using waste marble powder (WMP) and sugarcane bagasse ash (SBA) in the manufacturing of clay bricks. WMP was collected from local marble cutting workshops, whereas SBA was prepared by burning the waste sugarcane obtained from various sugar mills in the local area. Brick specimens incorporating 5%, 10%, 15%, and 20% of hybrid WMP and SBA were prepared at a local brick kiln. Burnt clay bricks were transported to the laboratory, and their mechanical and durability properties were evaluated. A reduction in weight per unit area of brick specimens incorporating waste materials was observed, allowing them to be easily handled and transported. Decreased compressive strength was due to the addition of waste materials in comparison with conventional clay bricks. However, waste percentages up to 15% satisfied the criteria for the minimum compressive strength as per the Building Code of Pakistan (BCP). All tested samples showed flexural strength greater than 0.65 MPa. Tested bricks incorporating 10% and 20% of waste materials had water absorption values of 18% and 21%, respectively, which are higher than that of conventional clay bricks. Moreover, bricks incorporating waste materials exhibited a higher initial rate of absorption than conventional clay brick; therefore, such bricks need to be wet well before use in masonry construction. Brick specimens showed less than 1% weight loss, and bricks exhibited no signs of distress and cracking after 50 freeze-thaw cycles. A decrease in compressive strength was observed due to sulphate exposure. However, specimens with 10% waste materials still satisfied the minimum compressive strength requirement of BCP. Based on this study, it can be concluded that bricks with up to 10% hybrid waste materials (WMP and SBA) will assist in the environmental issues of these wastes, leading to more sustainable and economical masonry construction.

Modelling of fresh properties and strength activity index with microstructure characterisation of ternary cement incorporating waste glass and granulated blast furnace slag

Research in innovative construction materials has focused on utilising supplementary materials in cementitious composites to promote sustainable development and reduce CO2 emissions. Within this context, this study aims to investigate the fresh properties and assess the pozzolanic activity of ternary blended cement by incorporating two industrial waste materials, namely waste glass (WG) and granulated blast furnace slag (GBS), as cement replacements up to 30%. A mixture design approach was employed for composition optimisation, and mathematical models were implemented to achieve this. XRD and SEM/EDS analyses were conducted to examine the structure and composition of the cementitious matrix. The results indicate that the setting time was prolonged compared to the reference mixture. Furthermore, based on the results of the SAI (Strength Activity Index) test, an acceptable level of strength development was demonstrated, confirming that WG and GBS possess the potential to replace cement while meeting the minimum strength requirements outlined in the specifications. Microstructure analyses revealed good adhesion between WGP, GGBS, and the cementitious binder. This research contributes to the development of eco-efficient binders that exhibit increased cement replacement ratios and qualities comparable to, or even superior to, traditional cement systems.

Enhancing mechanical and thermal properties of sustainable cement mortar through incorporation of olive solid waste aggregates

This research paper presents a comprehensive investigation into the characterization of cement mortar incorporating olive solid waste aggregates (OSW) as a partial replacement for natural sand. Different levels of OSW content (0%, 5%, 10%, and 15%) were used to create samples, enabling a comparison of their mechanical and thermal properties against the reference mortar. The primary objective of this study is to analyze the mechanical and thermal performance of lightweight cement mortar, with a secondary focus on establishing correlations between distinct testing methods, including compressive strength, sclerometer, and thermal tests. Mechanical properties were assessed through compressive strength testing. After a 28-day curing period, the mortar containing 5% OSW exhibited a compressive strength of 33 MPa. Notably, it demonstrated a 15.6% reduction in density compared to the reference mortar. An examination of the relationship between destructive compressive strength tests and non-destructive sclerometer tests (NDST) revealed a linear correlation, suggesting the effectiveness of the sclerometer test in estimating cement mortar compressive strength. Furthermore, we investigated the thermal characteristics of OSW-incorporated cement mortar. The mixture containing 5% OSW exhibited a thermal conductivity of 0.87 W/m·K, representing a 21% reduction compared to the reference mortar. These findings underscore the potential of OSW to enhance the thermal properties of the resulting cement mortar. Additionally, the observed correlation between compressive strength and thermal conductivity highlights a significant connection between these properties. This study primarily addresses the mechanical and thermal attributes of cement mortar incorporating OSW while also exploring correlations between testing methods. The resulting cement mortar meets the minimum strength requirements for structural applications as a construction material.

A biomechanical study of osseointegrated patient-matched additively manufactured implant for treatment of thumb amputees.

Thumb amputations leads to 50 % loss in hand functionality. To date, silicone vacuum prosthesis and autologous transplantation are the most adopted treatment solutions: nevertheless, vacuum prostheses lack in stability and cause skin issue and surgical treatment is not always accepted by patients. Osseointegrated implants were demonstrated to enhance stability, restore osseoperception and increase the time of prosthesis use. Thumb amputations present varying stump sizes: a standard size implant cannot address specificity of each patient, while a patient matched solution can meet surgeon requirements, by geometrical features of implant. The fixture presented in the current paper is the first additively manufactured patient matched osseointegrated implant for the treatment of thumb amputees. The current work aims to verify and validate a predictive finite element model (FEM) for mechanical strength of the presented fixture. FEM was demonstrated to correctly evaluate the mechanical strength of patient matched device. Minimum strength requirements were calculated in different core diameters: FEM were experimentally validated. Safety factor of 1.5 was guaranteed. Finally, considerations on performance of the prototype were carried out by means of insertion tests in Sawbones and axial pull-out force assessment. Cadaver tests to evaluate the entire procedure and production process are ongoing.