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AbstractFacility maintenance management (FMM) is essential for ensuring long-term values and to sustain project goals throughout the life cycle delivery process. However, in underdeveloped nations such as Ethiopia, facility maintenance management is an immature and underutilised process that requires a holistic intervention for practical improvement. The main aim of this study was to identify and prioritise critical factors that affect the effectiveness of FMM, with a focus on public universities in Ethiopia. Initially, a total of thirty-three (33) crucial variables were identified with a systematic literature review and desk study. To collect primary data, a survey research design approach was utilised using questionnaires and informant interviews. A total of seventy-five (75) data sets were obtained from 180 online surveys for conducting exploratory factor analysis (EFA). The outcome of the study revealed thirteen (13) critical attributes grouped into four factors that affect the effectiveness of facility maintenance management practises. The final four-factor model includes F1, internal processes and organisation; F2, community culture, learning, and growth; F3, impacts of design and construction quality; and F4, facility maintenance approach and management. This study indicated that facility maintenance management practises in public universities in Ethiopia are immature and require extensive enhancement. The identified influencing factors highlight the need for a comprehensive intervention to promote improved facility maintenance management practises and applications in Ethiopia. Further research is needed to analyse a wider range of attributes and data using confirmatory factor analysis.

The main objective of this study was to examine the combined effect of ground recycled concrete cement (GRC) and thermo-activated recycled concrete cement (TARC) on properties of mortar. The physical, chemical and microstructural tests were conducted to characterize GRC and TARC before mortar mixtures were produced. The microscopic morphology of GRC and TARC revealed uneven edges and a rough surface that is slightly porous. The GRC and TARC powders were used to replace cement in the range of 0-50% at increments of 10% by volume. The fresh, mechanical, microstructure, and durability characteristics of mortar were tested for different proportion of GRC and TARC as partial replacement of cement. The usage of GRC and TARC decreases the workability of mortar marginally. However, the mechanical performance of the mortar mixtures showed an increasing trend when GRC and TARC share increases in the mixture. Predominantly, compressive strength, bulk density, and ultrasonic pulse velocity (UPV) have all been increased by as much as 20% cement replacement. Furthermore, the incorporation of GRC and TARC enhances the mortar’s durability properties. The microstructure analysis reveals that 20% replacement (GT20) mix has superior structural compactness. In general, partially substitution of GRC and TARC by ordinary Portland cement improves several characteristics of mortar. This will help solve the most prevalent problems that concrete produces, including the high embedded carbon dioxide creation, the high resource usage, and the high waste generation after demolition.

The integration of BIM with other digital advancements has demonstrably led to an increase of performance in the Architecture, Engineering, Construction and Operation (AECO) industry. This integration not only is showing promising results in boosting the industry's performance, but also the productivity and promotes data-driven decision-making. Despite these benefits, there are limited studies that address the integration of BIM and digital data for managing built-assets in general and in developing countries in particular. To fill this gap, a closer assessment of current built-asset information management practice is necessary. The assessment of the practice examines how digital processes and/or technology can be seamlessly integrated into existing practices. In this regard, this study aims to provide valuable insights into increasing the maturity of built-asset information management by integrating digital data with BIM. The study uses a case-based research design using built-assets (universities in Addis Ababa) as public building representative to capture the prevailing information management practices in Ethiopian public buildings. The findings reveal that traditional paper-based practices still dominate the management of built-assets. This leads to difficulties in terms of data loss, unavailability, inaccuracy, and unreliability, all of which are detrimental to the overall performance. Based on these findings, a conceptual framework is designed to improve the performance of built-assets and help owners, end-users, and managers in defining data and information requirements for BIM-enabled asset information management. The framework delineates processes for structured information requirements definition and validation of various asset data from varying sources. The framework utilizes a BIM-enabled platform as a single source of truth and offers a comprehensive solution to the identified challenges. The findings of this study holds significant promise for improving the existing practice of built-asset information management within the study context.

The cement industry is known for being highly energy-intensive and a significant contributor to global CO2 emissions. To address this environmental challenge, this study explores the potential of using the waste materials of steel slag (SS) and eggshell powder (ESP) as partial replacements for cement in alkali-activated mortars (AAMs) production, activated by NaOH and Na2SiO3. Mortar samples are prepared with 50% of ordinary Portland cement (OPC) as part of the total binder, and the remaining 50% is composed of ESP, incrementally replaced by SS at levels of 10%, 20%, 40%, and 50%. The activation process was performed with an 8% NaOH concentration and a silica modulus of 2. Key findings include that the workability of AAMs decreased with increasing SS content, requiring admixtures like superplasticizers or additional water to maintain workability. At 50% SS replacement, the water consistency and slump flow values were 32.56% and 105.73 mm, respectively, with a setting time reduction of approximately 36%, losing plasticity within 2 h. Both absorption capacity and porosity decreased as SS content increased from 10% to 50% of ESP. Additionally, the bulk density, compressive strength, and uniformity of the hardened mortar samples were enhanced with higher SS content, achieving maximum compressive strength (28.53 MPa) at 50% SS replacement after 56 days of curing. Furthermore, OPC-based AAMs incorporating SS and ESP demonstrate good resistance to sulfate attack and thermal heating. Microstructural analysis reveals the presence of C–S–H, C–A–S–H, and N–A–S–H phases, along with minor amounts of unreacted particles, and the microstructure shows a dense, highly compacted, and homogeneous morphology. These findings suggest that replacing eggshell powder with up to 50% steel slag enhances the hardened properties of AAMs. Further research is recommended to explore cement-free alkali-activated granular ground blast furnace slag (GGBFS) with ESP for more sustainable construction solutions.

AbstractThe purpose of this study is to develop a performance measurement model based on maturity dimensions or criteria and KPIs identified through an extensive literature review. Using the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method, a maturity model is developed by analyzing 12 criteria/dimensions and 51 KPIs. The importance of each criterion and KPI is analysed through focus group discussions with experts. A fuzzy method is used to resolve the fuzziness and uncertainty of the expert judgments. The fuzzy DEMATEL method is used to analyse the data, and the values of R+C and R-C are computed. In order to visualize the complex relationships, identify the most important criteria of building maintenance and analyse their mutual influence, a cause-effect diagram is created by mapping all sets of coordinates. Accordingly, C8 (culture and leadership), C1 (maintenance policy and strategy), C6 (design life), and C5 (maintenance information management) are assigned to the cause group. These four criteria are identified as the most critical criteria because they can influence the remaining criteria categorized in the effect group. For negative values of (R-C), C2, C3, C4, C7, C9, C10, C11, and C12 are categorized in the effect group. A five-level hierarchical model was developed to measure maturity performance based on the weighted average of the criteria and KPIs of the fuzzy DEMATE outcomes. The current model covers multiple measurement dimensions/perspectives as a measurement criterion for building maintenance maturity. The model is important for decision makers to identify weaknesses and strengths and incrementally improve the weaknesses in a continuous improvement approach. The new model can help decision makers determine the current state of maintenance maturity and plan actions to improve efficiency and effectiveness to create sustainable and productive building assets.

The purpose of this study was to evaluate the mechanical properties of concrete specimens produced with recycled aggregate (RA) from construction demolition waste (CDW) based on alkaline activated slag-fly ash (AASF). The recycled aggregate concrete mixtures (RAC) were designed using DMDA method, with RA used as a 30%, 40%, and 50% partial replacement for natural aggregate (Category 1) and with Na2O doses of 4%–8% and modulus ratios of 0.6–1.4 (Ms = SiO2/Na2O; Category 2). The results showed that the inclusion of RA negatively affected the mechanical properties of RAC specimens, with recycled coarse aggregate exhibiting less of a negative effect than recycled fine aggregate. The concrete mixtures exhibited mechanical strength values of 20.7–35.9 MPa and UPV values of 3692–4200 m/s at 28 days of curing age. Concrete characteristics were significantly better in the mixtures produced using higher alkaline concentrations than in those produced using lower alkaline concentrations.

The purpose of this study is to examine the effects of partially replacing cement with a blend of marble waste powder (MWP) and granite waste powder (GWP) in mortar, with the goal of reducing the environmental harm caused by cement. The investigation included an analysis of the distinctive properties of the two waste powders individually, as well as initial tests with various ratios to determine the optimal combination that yields the highest strength. It was observed that a 50% MWP to 50% GWP blend produced the most substantial strength. Subsequently, the effect of partial replacement of cement with the blend of marble and granite waste powder (MGWP) at various increments of 5%, ranging from 0% to 30%, was evaluated by subjecting the mortar to numerous tests to assess its workability, physical, mechanical, durability, and microstructural properties. The analysis of the employed waste powders confirmed that the GWP can be classified as a natural pozzolan material belonging to Class N. As the proportion of MGWP increased, the workability of the mortar mixes decreased. However, incorporating MGWP up to 15% resulted in enhancements in bulk density, compression strength, and homogeneity, with the best performance observed at a 10% MGWP content. Microstructure analysis confirmed that the addition of MGWP enhanced the bonding of C–S–H and C–H, leading to a denser morphological structure in the mixes, particularly at a 10% MGWP content. The utilization of MGWP not only significantly reduced the carbon footprint associated with cement production but also fostered sustainability.

The effects of thermoactivated recycled concrete cement (TARC) on mortar as a partial replacement for cement was examined. TARC is derived from concrete waste through a series of processes. Different mortar mixtures were tested, ranging from 0% to 50% TARC in 10% increments. A comprehensive range of tests was conducted to assess the properties of the mortar, including fresh, mechanical, microstructure, and durability evaluations. The fresh test indicated that the incorporation of TARC impacted the flow of mortar, leading to reduced workability as the percentage of replacement increased. Regarding mechanical performance, using 20% TARC resulted in improved compressive strength, bulk density, and ultrasonic pulse velocity (UPV). Microstructural analysis using thermogravimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR) revealed that the TARC mix exhibited advantageous thermal properties, enhanced FTIR spectra, and a denser microstructure, thereby enhancing the durability of the mortar. Overall, substituting OPC with TARC significantly reduces the carbon footprint associated with cement production, promoting sustainability and contributing to a circular economy in the construction industry.

This study investigated the impact of using cow dung ash (CDA) as a partial replacement for ordinary Portland cement (OPC) in mortar. Mortar mixes are prepared by replacing OPC with CDA at varying levels: 5%, 10%, 15%, 20%, 25%, and 30%. The chemical composition of CDA shows that it is composed primarily of SiO2, Al2O3, and Fe2O3, with a significant amount of loss of ignition. The workability, hardened properties, and microstructure of CDA-containing mortars are also analyzed. The increasing CDA content in mortar reduces workability and, beyond 5%, it causes high water absorption due to CDA’s porous nature and unremoved organic compounds. This impacts the density and compressive strength of the hardened mortar as well as compromising its homogeneous characteristics. When using 5% CDA, the bulk density and compressive strength of the mortar are comparable to those of the control mixes. Nonetheless, as the proportion of CDA increases, both the bulk density and compressive strength of the mortar diminish. The thermal stability of mortar mixes with 10%, 20%, and 30% CDA is unaffected at temperatures between 500 °C and 600 °C. The Fourier-transform infrared spectroscopy (FTIR) analysis reveals the presence of unreacted particles and wide stretched C–S–H gels in the mortar samples. In general, the results suggest that CDA can be utilized as a substitute for OPC at a ratio of up to 10% in the manufacturing of mortar and can serve as a feasible alternative cementitious material.

The production of cement results in the depletion of natural resources and consumption of huge energy and CO2 emissions to the environment that cause global warming and climate change. To alleviate the problem, there is a growing interest of researchers to find an alternative material to partially cement by industrial and agricultural wastes. This research was therefore aimed to examine the potential of using coffee husk ash (CHA) as partial replacement for ordinary Portland cement (OPC) in C-25 concrete production. Concrete mixtures were prepared by partially replacing cement with CHA in different proportions (0%, 5%, 10%, and 20%) by weight with a constant w/c of 0.5. The consistency, setting time, workability, compressive strength, water absorption, sulphate attack, Fourier transform infrared (FTIR), and thermo gravimetric (TGA) tests were conducted on concrete samples. The test results revealed that the workability of mixtures showed a decreasing trend with an increase in the share of the CHA content in which the measured slump flow values ranged between 15 and 35 mm. Contrarily, the setting time of concrete mixtures showed an increasing trend with an increase in CHA content. The initial and final setting times were in the range of 67–126 minutes and 310–524 minutes, respectively, which is in the range of the standards. The compressive strength of concrete decreased with an increase in the share of the CHA, in which the results were measured in the range of 35.1–22.7 MPa for the 28th day sample with 5% and 20% of CHA, respectively. However, it increases as the curing days increase, whereas the water absorption of the concrete increases as the CHA increases but decreases as the curing days increase due to the porous nature of the CHA. From the study microstructure of concrete using Fourier transform infrared spectroscopy and thermogravimetric analysis, differential thermal analysis results show that the C-S-H gel would be from 950–1100 cm−1 wavenumber and at 500oC, and the CHA sample was decomposed and mass loss was observed at 500oC. In general, it was also observed that, from the compressive strength, the concrete satisfies its design strength up to 10% replacement level without compromising the performance of concrete.

The main goal of this review paper was to study the physical and chemical properties of agricultural crop wastes and their potentials to partially replace in production of mortar and concrete. Bamboo leaves’ ashes (BLA), banana leaves’ ashes (BNLA), corncob leaves’ ashes (CCA), groundnut ashes (GNA), rice husk ashes (RHA), and sugarcane bagasse ashes (SCBA) were selected to be reviewed. The chemical composition of these agricultural wastes revealed that the they are basically composed of alumino-siliceous materials conforming the requirement of pozzolanic materials. Compared with cement, they have finer particle size and higher surface area. The effect of partial replacement of cement by BLA, BNLA, CCA, GNA, RHA, and SCBA on the properties of fresh concrete (consistency, workability, and setting time), mechanical properties (compressive and tensile strength), microstructure (scanning electron microscopy, derivative thermogravimetry, and X-ray diffraction), and durability (ultrapulse velocity, water absorption, and sulphate attack) of concrete was recapped. The inclusion of BLA, CCA, RHA, and SCBA as partial replacement of cement reduced the workability of concrete due to their finer particle size. The mechanical performance of concrete showed enhancement with partial replacement of cement by BLA, RHA, and SCBA due to the involvement of amorphous silica in secondary reaction to produce densified tetrahedral gel. Consequently, uniform and denser morphology was formed, and durability was enhanced as densification of hydrated gel increased. In general, the review exposed that agricultural crop wastes satisfy pozzolanic material properties and have strong potential to replace cement up to 10% without compromising the performance of concrete.