Mechanical Performance and Thermo-Physical Properties of Cement Mortar Incorporating Hybrid Slags

Owing to the growing environmental pressure to reduce waste and pollution, the effective utilization of industrial solid wastes in construction applications has gained notable attention. This study investigates the mechanical and thermal properties of cement mortars incorporating two types of waste slags. Ferrochrome (FeCr) slag aggregate was used as a replacement for sand at the ratios of 25, 50, 75 and 100 wt. %. Ground granulated blast furnace slag (GGBS) has been used as a partial replacement of cement at the ratio of 25 wt. %. Compressive strength, permeable voids content and thermal conductivity tests have been conducted after 28 days of curing. The microstructure characteristics have been investigated by scanning electron microscope (SEM) equipped with energy dispersive analytical x-ray unit (EDAX). The experimental results revealed that FeCr waste aggregates could satisfactorily replace for natural fine sand in cement mortars up to 25 wt. % without a remarkable degradation of the compressive strength. Furthermore, Increasing replacement ratios of FeCr aggregates over 25 wt. % have resulted in noticeable decrease in thermal conductivity and an increase in the permeable voids content of cement mortars. The integration of GGBS with FeCr aggregates leads to enhanced compressive strength, reduced voids content and contribute to improved microstructure. The developed mortars with comparatively improved thermal resistance can be recommended for several structural and non-structural applications especially in hot weather regions.The authors would like to acknowledge the financial support provided by Sohar Port and Free Zone Company under Sultan Qaboos University Grant No. CR/ENG/ CAED/18/07

ABET Accreditation: An Engineering Experience from Sultan Qaboos University, Oman

[EN] The Accreditation Board for Engineering and Technology (ABET) accredits college and university programs in engineering under the Engineering Accreditation Commission (EAC). The process follows Engineering Criteria (EC) 2000, which focuses on outcomes (what is learned) rather than what is taught. This paper presents an overview of the processes developed by the civil engineering (CE) program at Sultan Qaboos University to satisfy ABET Criteria 2, 3, and 4. The program had a successful accreditation visit in November 2013. Program educational objectives (PEOs) were developed. A review and revision process for PEOs was also developed. ABET student outcomes (SOs) were adopted by the CE program. SOs were broken into outcome elements. Key performance indicators were developed for each outcome element, according to the six levels of Bloom’s taxonomy for cognitive domain. The process used direct indicators from student work as well indirect survey instruments. The program has developed a detailed and systematic approach for assessment of SOs with feedback and follow-up on implementation of actions for continuous improvement. Planning for the next accreditation cycle of SO assessment proved valuable, as the new accreditation committee started executing an already laid out work plan.Hassan, H.; Al-Jabri, K. (2016). ABET Accreditation: An Engineering Experience from Sultan Qaboos University, Oman. En 2nd. International conference on higher education advances (HEAD'16). Editorial Universitat Politècnica de València. 269-277. https://doi.org/10.4995/HEAD16.2015.269126927

Comparison of Seismic and Wind Actions on Medium to High-Rise Buildings in Muscat, Oman

This study is a comparison of wind and seismic loads on medium and high-rise buildings in Muscat, Oman. It uses the proposed Omani Seismic Code and Eurocode EN1991 for seismic and wind calculations, respectively. Muscat falls under Zone-1 in the Omani seismic code and experience basic wind speed of 30 m/sec. The research investigates buildings with varying aspect ratios (1:1 and 1:2), heights (11, 15, and 19 stories), and structural layouts (frame only, core shear wall, and corner shear wall), using ETABS for structural analysis. The findings reveal that seismic actions are generally more significant than wind actions for buildings in Muscat. In frame-only structures, wind-induced base shear ranges from 16%-33% for 1:1 aspect ratio and 21%-43% in the x-direction and 10%-20% in the y-direction for 1:2 aspect ratio, when compared to seismic actions. This difference decreases with increasing building height. Incorporating shear walls notably reduces the maximum lateral displacement across all scenarios, with core-located walls being most effective, leading to a 49% reduction in lateral displacement. Shear walls also substantially mitigate first-story column shear forces and bending moments. The study concludes that seismic actions are more critical than wind actions in Muscat for simple moment-resisting frame systems. Additionally, using shear walls in these buildings is highly beneficial for controlling lateral displacements and reducing member forces

Effects of Elevated Temperatures on the Compressive Strength Capacity of Concrete Cylinders Confined with FRP Sheets: An Experimental Investigation

Due to their high strength, corrosion resistance, and durability, fiber reinforced polymers (FRP) are very attractive for civil engineering applications. One of these applications is the strengthening of concrete columns with FRP sheets. The performance of this strengthening technique at elevated temperature is still questionable and needs more investigations. This research investigates the effects of exposure to high temperatures on the compressive strength of concrete cylinders wrapped with glass and carbon FRP sheets. Test specimens consisted of 30 unwrapped and 60 wrapped concrete cylinders. All specimens were exposed to temperatures of 100, 200, and 300°C for periods of 1, 2, and 3 hours. The compressive strengths of the unwrapped concrete cylinders were compared with their counterparts of the wrapped cylinders. For the unwrapped cylinders, test results showed that the elevated temperatures considered in this study had almost no effect on their compressive strength; however, the wrapped specimens were significantly affected, especially those wrapped with GFRP sheets. The compressive strength of the wrapped specimens decreased as the exposure period and the temperature level increased. After three hours of exposure to 300°C, a maximum compressive strength loss of about 25.3% and 37.9%, respectively, was recorded in the wrapped CFRP and GFRP specimens

INVESTIGATION OF NOISE EXPOSURES, PERCEPTION, AND HEALTH EFFECTS IN DIFFERENT MICROENVIRONMENTS IN A UNIVERSITY COMMUNITY

This study aims to assess noise levels in selected outdoor and indoor microenvironments in a University community in Oman. The perception of noise levels within the Sultan Qaboos University campus was investigated through a survey study. Also, the effect of exposed noise levels on annoyance and sleep disturbance were predicted including their potential risk on cardiovascular health. Among all the measured parameters, it was found that outdoor (41.6%-50%) and indoor (38.5%-46.2%) microenvironments have exceeded the critical levels of 55 dB during morning and afternoon periods. The respondents (698 people) identified traffic and indoor building-related activities as the main sources of noise levels but the majority (44%) of them rated their impact as low. However, more than 30% of the respondents considered traffic as the main contributor to University noise levels. The percentage of highly annoyed persons was predicted to be high in outdoor areas especially in the residential (25%) and near the hospital (13%) areas. However, indoor environments including construction materials and structures labs (14%) showed similar annoyance rates. Also, the percentage of high sleep disturbed persons was found higher in residential areas (7.4%) areas compared to hospital areas (5.3%) locations. The study concluded that there might be an association between the exposed noise levels and the risk of developing cardiovascular diseases. This is the first study that has provided a high spatial variability noise exposure levels across a University environment in Oman, this will contribute to designing future sustainable mitigation strategies to improve the health and well-being of the exposed population. The study has provided a baseline knowledge needed for future epidemiological studies

Cranioplasty in Oman: Retrospective review of cases from the National Craniofacial Center 2012–2022

Objectives: Cranioplasty is a complex craniofacial and neurosurgical procedure that aims to reinstate the architecture of the cranial vault and elevate both its aesthetic and neurological function. Several reconstructive materials have been thoroughly explored in the search for the optimal solution for cranioplasty. This study aimed to evaluate different material used for cranial reconstruction in Oman. Methods: This retrospective study included all patients who had had cranioplasty procedures performed at Khoula Hospital, Muscat, Oman, from 2012 to 2022. Demographic information, the characteristics of the cranial defect and any complications that occurred post-operatively were analysed. Results: A total of 47 patients were included in this study. The most common cause of cranial defects was craniectomy following traumatic head injury (70.2%) along with excision of fibrous dysplasia (10.6%). The most frequently utilised material for cranial repair was autologous bone grafts (n = 28), followed by polyetheretherketone (PEEK; n = 14). Interestingly, the replacement of bone grafts from previous craniectomy showed a notably high resorption rate (71.4%), in contrast to split calvarial grafts (0%) and other types of bone grafts (14.3%). Additionally, delayed graft infection was observed in 3.6% of the bone graft group and 7.1% of the PEEK group. Conclusion: Patient-specific alloplastic implants such as PEEK have gained popularity for large and complex cranioplasty, as they provide excellent aesthetic outcomes and leave no donor site morbidity. In contrast, bone grafts remain the gold standard for small to medium-sized cranial defects. Keywords: Bone Grafting; PEEK; Oman

Properties and structural behavior of concrete containing fine sand contaminated with light crude oil

Mixing crude oil contaminated sand with cement and using this mix as an alternative construction material is considered an innovative and cost-effective approach to reduce its negative environmental impact. In this study, the compressive and splitting tensile strength of concrete with different levels of light crude oil contamination (0, 1, 2, 6, 10 and 20%) were evaluated. Microstructure observation was also conducted to better understand better on how the oil contamination is affecting the concrete properties. The bond strength of steel reinforcement and a comparative evaluation of the flexural behaviour of steel reinforced beams using concrete with 0% and 6% oil contamination was carried out. Results showed that concrete with light crude oil contamination can retain most of its compressive and splitting tensile strength at a contamination level of up to 6%. A good bond between the steel reinforcement and concrete can be achieved up to this level of oil contamination. The concrete beam with 6% oil contamination exhibited only a 20% reduction in the moment capacity compared to a beam using uncontaminated concrete. Simplified empirical equations were also proposed to reliably predict the mechanical properties of concrete containing oil contaminated sand

A self-sensing and self-heating planar braided composite for smart civil infrastructures reinforcement

Allocating different capabilities to structural elements simultaneously is still challenging. In this study, a field-applicable multifunctional planar braided composite with the abilities of reinforcing, self-sensing and self-heating was developed for the first time. In this route, three commercial fabrics were used, including cotton, cotton/polyamide, and polyester. The fabrics were first chemically treated and then coated with a carbon nanomaterial-based polymeric conductive paste using screen printing with different concentrations and layers. The samples were then covered and sealed with a thermoplastic polyurethane-based polymer to avoid environmental factors effects. Smart planar composites (SPC) were also used as reinforcement for cementitious specimens. The electrical conductivity and joule heating capability of the samples were also evaluated. The microstructure of the SPCs was investigated using various tests. The mechanical and self-sensing performances of the cementitious composite reinforced with different SPCs were assessed using different load patterns. The results showed a heating rate of 0.44 ˚C/s, a joule heating power of 0.7 W/˚C, and a maximum temperature of 44 ˚C which proved the proper heating capability of the cementitious composites reinforced with SPCs. The great correlation between electrical resistivity changes and strain values indicated the high potential of the composite in strain sensing for different applications. The SPCs also improved the post-crack behaviour of the specimen and its flexural strength and failure strain by approximately 50% and 118%, respectively. The outcomes of this study draw a bright horizon in multifunctional braided composite development with different applications in civil infrastructures, which is a crucial step for intelligent cities' advances.This work was partly financed by the Institute for Sustainability and Innovation in Engineering Structures (ISISE) and the R&D Unit of the Centre for Textile Science and Technology (2C2T) founded by the Portuguese Foundation for Science and technology (FCT) under the reference “UIDP/00264/2020”. The first author also acknowledges the support provided by the FCT/PhD individual fellowship with reference of “2021.07596.BD”

The behaviour of steel and composite beam-to-column connections in fire.

Recent fire tests on the Cardington full-scale test frame and observations from real fires have demonstrated the significance of connections in fire, when they can have beneficial effects on the survival time of the structure. The lack of experimental data on the behaviour of steel and composite connections in fire means that this is insufficiently addressed in current design codes and also limits the effective use of numerical models. However, recent experimental tests on small-scale specimens have shown that it is possible to derive accurately the moment-rotation relationships at elevated temperature and have established the principles by which this could be achieved. In order to extend the scope to include further parameters, five series of tests have been carried out in a portable connection furnace at the Building Research Establishment. The test series includes flush and flexible end-plate bare-steel connections, and flexible end-plate composite connections. The testing procedure and the resulting behaviour are described. The fire test temperature profiles across the connections are detailed and the connection failure mechanisms are discussed. From the test results, moment-rotation- temperature curves for different connection types are derived. The degradation of connection characteristics is compared with that of structural steel. The experimental behaviour is also compared with the results obtained from an existing finite element analysis developed to model connection response in fire conditions. The experimentally derived connection characteristics have been incorporated within a parametric study of a typical sub-frame, to study the effect of connection type, end-plate thickness, concrete strength, load ratio, and connection temperature. Analysis is extended to a three-dimensional sub-frame. The patterns of behaviour observed in the connection tests is compared with that of the connections in the large-scale fire tests on the composite building at BRE's Cardington laboratory. Based on knowledge about the behaviour of connections at elevated temperature, a component-based model is developed for the elevated temperature response for flexible end-plate connections, both as bare-steel and composite. This is based on the response of constitutive parts of connection. The model is easy to use, and capable of modelling the entire non-linear range of connection behaviour. The predicted response is compared with that recorded experimentally

Endometriosis at Caesarian Section Scar

Endometriosis is a common gynecological condition which is sometimes presented to general surgeons as a lump in the abdomen. It can pose a diagnostic dilemma and should be in the differential diagnosis of lumps in the abdomen in females. Diagnosis is usually made following histological examination. This is a case report of abdominal wall endometriosis following caesarian section. This report discusses and evaluates the incidence, pathophysiology, course, diagnosis, treatment and prevention of this condition