Catálogo de publicaciones - revistas

<jats:p xml:lang="en">Red mud (RM) is a by-product of the Bayer process in aluminum industries, and its disposal leads to environmental imbalance. This study aimed to utilize RM as a cementing material in concrete to mitigate the negative environmental impact associated with its disposal. Initially, red mud was subjected to calcination at 600ºC for 0-6 hours with increments of 1 hour. Various characterization studies, including particle size analysis, BET analysis, XRF, XRD, TG-DTA, and SEM, were conducted to investigate the physical, chemical, and morphological changes in the RM resulting from calcination. Regarding the physical properties, specific gravity, and particle size values significantly decreased, while specific surface area and mass losses increased up to 2 hours of calcination due to moisture loss. Subsequently, contrasting results were observed. XRF analysis revealed abundant presence of iron oxide (Fe2O3), alumina (Al2O3), and silica (SiO2) in all the calcined red muds. Mineralogical phase changes, such as the transformation of goethite to hematite and gibbsite to alumina, were observed through XRD analysis. Morphological changes were observed using SEM analysis, showing a loose structure up to 2 hours of calcination, followed by a denser structure. Furthermore, all the calcined RMs were incorporated into cement at a 10% weight ratio, and their pozzolanic properties were investigated. Based on the results, the 2-hour calcined RM exhibited superior cementitious properties, including high compressive strength and strength activity index (46.27 MPa and 117.24%, respectively). Similarly, scanning electron microscope analysis was conducted to understand the behavior of the 2-hour calcined red mud in cement mortar, demonstrating better C-S-H gel formation in the corresponding mix. The present study concludes that 2-hour calcined red mud can be effectively used as a cementing material in concrete.</jats:p>

<jats:p xml:lang="en">The decrease in resources in the world has led people to produce new solutions for the more efficient use of resources and to use various management techniques. One of the techniques used is Value Engineering. Value Engineering strives to increase the value of structures by optimally organizing each component that makes up the structure. Increasing the value of a structure is possible by eliminating all the unnecessary costs in line with certain criteria and by providing the optimal solution between the owner, the user, and the contractor's objectives, that is, the duration, cost, and quality. This study includes the changes made by the Value Engineering team to increase the value of the materials extracted from the submarine in a Container Port Terminal project without harming the environment and by making them reusable. While increasing the project value, it is also aimed to reduce the project duration and cost by considering the sustainability criteria. In the original project, there was the idea of creating a clay pool while dewatering, separating the material, filling the loose sand into the reclamation area, and removing the sludge material by sea. With the recommendation of the value engineering team, the dewatering process was transformed into a method of directly pressing the dredged loose sand into the breeding area, filtering the material with geotextile tubes, and removing the material by loading it on the pontoons. With this change in the project, 42% savings were obtained from the cost and 21% from the project duration.</jats:p>

<jats:p xml:lang="en">The need for shelter after disasters is a common issue, and its planning should occur during the risk management phase, not in the post-disaster process. Following the initial few weeks of emergency aid, the rehabilitation phase comes into play, encompassing the period spent in temporary housing units until a transition to permanent housing is achieved. Like the emergency aid phase, this phase cannot be sustained solely by emergency shelter tents due to its extended duration, which is shorter than the time required to construct permanent housing. Specific designs suited to the rehabilitation phase are necessary. However, many post-disaster temporary housing implementations have failed to meet the requirements.&#x0D; &#x0D; In this context, the study's central issue is identified as the "necessity of creating a decision model to evaluate post-disaster temporary housing." The foundational elements of a decision/evaluation model include determining the criteria and their weights. This study is based on the premise that the importance weights of criteria should differ according to the distinct characteristics of regions. Thus, a "criteria weighting method" and an evaluation model are proposed, considering factors such as varying urban density, household size, urban accessibility, and climatic conditions based on regional differences.</jats:p>

<jats:p xml:lang="en">The brick is one of the most used building materials used in the masonry construction. Conventionally burnt clay bricks are used, these bricks are manufactured from the clay and burnt in a kiln at a very higher temperature. This results in very high amount of CO2 emission and also has high embodied energy, this is highly affecting the environment.&#x0D; Compressed bricks is one of the sustainable solution to overcome this issues of high CO2 emission and embodied energy. The adoption of sustainable alternatives, such as compressed bricks incorporating supplementary cementitious materials or environmentally friendly brick manufacturing processes, can help mitigate these issues and promote more sustainable construction practices.&#x0D; In this study attempts have been made to manufacture and test the bricks with propostioning the soil i.e. mix of locally available soil with sand, cement as the cementitious materials and SCMs like flyash &amp; GGBS. The research methodology involve the formulation of different mixtures with varying proportions of SCMs. The specimens were then prepared using a compression molding technique and cured under controlled conditions.&#x0D; This research paper aims to investigate the effects of incorporating supplementary cementitious materials (SCMs) on the properties of compressed bricks. The study focuses on evaluating the density, compressive strength, water absorption, efflorescence, as well as calculating the embodied energy and carbon dioxide emissions associated with the production of these bricks.&#x0D; Furthermore, the paper presents a comprehensive analysis of the embodied energy and CO2 emission associated with the production of the compressed bricks. These calculations take into account the energy consumed and CO2 emitted in the manufacturing process, including raw material extraction, transportation, and brick fabrication.&#x0D; The results of the study demonstrate the influence of SCMs on the properties of the compressed bricks. The analysis of embodied energy and CO2 emissions provided valuable insights into the environmental sustainability of the brick production process.</jats:p>

<jats:p xml:lang="en">Geopolymers cured under ambient temperature ultimately reach final strength in the long term. Heat curing triggers early strength gain, but it may cause detrimental effects in long-term depending on the mixture components and curing conditions. This study examined the influence of long-term curing duration on the properties of geopolymer produced through the geopolymerization reaction between Datça Pozzolan and sodium silicate and potassium hydroxide solutions. The specimens were heat cured at 90°C, 95±5% RH for 24 h initially and then kept under ambient conditions until the tests were conducted at 7, 90, and 365-day. The results showed that applied initial heat curing was proper to achieve early and long-term strength. Mortars with 12.5 molarity and 2.5 activator ratio had the highest strength gain at both 7 and 365-day. The physical and mechanical improvement achieved at 90-day was higher compared to 90-to-365-day. There was an almost twofold strength improvement after 365-day. A higher rate of improvement was obtained when the activator ratio was low, that is, the improvement decreased inversely as the sodium silicate content of the mortar increased. An increasing trend was observed in the plot of compressive strength as function of ultrasound pulse velocity, and the slope values presented a strongly related linear function relation.</jats:p>

<jats:p xml:lang="en">The use of recycled aggregates is crucial for a more sustainable environment and economy. In this study, the properties of recycled aggregate-based SIFCONs were examined. In the scope of the study, compressive strength, high-temperature resistance, sorptivity and fracture energy of SIFCONs produced with recycled aggregate were investigated. The results were compared with those of the limestone-bearing SIFCONs. It was determined that the compressive strength and fracture energy of SIFCONs produced with recycled aggregate were 61.2 MPa and 14.9 N/mm, respectively. Although, these values are lower than those of SIFCONs produced with limestone, it has been determined that recycled aggregates are advantageous in high-temperature resistance. The results demonstrated that the recycled aggregate could be used in the production of SIFCON.</jats:p>