Sustainable Concrete Innovation: Crumb Rubber as a Partial Fine Aggregate Replacement

The exponential growth of the automobile industry contributes a significant accumulation of waste tires, presenting a substantial environmental challenge due to their non-biodegradable nature. This study investigates the potential of using crumb rubber produced from waste tires as a partial replacement for natural fine aggregates of concrete, aiming to enhance the material's properties while mitigating environmental impact. The mechanical and durability characteristics of concrete introducing 5%, 10%, and 15% crumb rubber were determined through various tests, including compressive strength, stress-strain behavior, and impact resistance. Results indicate that while there is a slight decrease in compressive strength with increased rubber content, the post-cracking behavior and impact resistance improve significantly, with energy absorption capacities increasing by 75%, 125%, and 158.4% for 5%, 10%, and 15% replacements, respectively. Additionally, durability tests reveal that rubberized concrete shows reduced chloride ion penetration and improved resistance to acid attack, with 30% reduction in chloride penetration at 15% rubber content. The findings suggest that incorporating crumb rubber can enhance the ductility and durability of concrete, making it a viable and sustainable alternative in construction, particularly in applications such as road pavements where impact resistance is crucial. This study contributes to the ongoing research on sustainable construction materials and emphasizes the importance of recycling waste materials to reduce environmental impact

المنفى بعين الراوي الطفل ومركزية الأيقونة في قصة "أرض البرتقال الحزين" "لغسان كنفاني"

This study aims to investigate the experience of exile and its psychological effects on the stability of Palestinian children in the story «The Land of the Sad Oranges» by the Palestinian writer Ghassan KANAFANI. The writer portrays the anxieties of pain and helplessness faced by children after losing their safety, which deepened by the non-resistance of their parents' generation to the authority's arbitrary decision. This created a division in the language of communication within Palestinian families, as exile became a psychological confrontation between the homeland – the origin of truth and reference – and the unfamiliar and foggy place. The author attributes this narrative description to the «child» witness, who beheld and documented the suffering of his family in different places, thus generating narrative expressions resulting from an awareness of the unspoken and making it a realistic horizon in its political and social contexts. The narrator's voice merges with that of the author as they seek an alternative to belonging through documenting the situation

خطبة البيعة لأبي بكر الصّدّيق: دراسة بلاغيّة وأسلوبيّة

The speech was read rhetorically by addressing the knowledge of some of its rhetorical characteristics. On the other hand, some of its stylistic characteristics were known; For example: stylistic options such as functional, structural and expressive options, and some of their stylistic levels, such as the phonetic, and semantic level…etc., were known, so that loud and intense sounds are the most commonly used; This confirms the importance of its tolerance of the affairs of the parish, and the semantic fields that dominated this discourse were known to achieve some meanings and connotations that confirm the extent of the responsibility. As for intertextuality, this sermon knew the presence of the old text along with the present text

A study on post-fire durability performance of concrete

Concrete structures are often exposed to fire hazards, which can significantly affect their durability and structural integrity. Post-fire durability assessment is crucial to understanding the residual strength and long-term performance of concrete after exposure to elevated temperatures. Limited research has concentrated on durability attributes, with the majority examining primarily mechanical aspects. We have thus initiated the endeavor. This study aims to evaluate the post-fire durability characteristics of concrete, focusing on strength retention, microstructural changes, and degradation mechanisms. This investigation adapted concrete compositions containing 75% recycled marble aggregate (RMA) to the mix. We exposed the prepared concrete to various temperature conditions, including 200°C, 400°C, 600°C, and 800°C. The study examined the concrete's durability features, including their acid, chloride, and carbonation resistance. This investigation revealed that the fire significantly impacted the mechanical and durability properties of the concrete. The results show that fire, in any temperature environment, significantly reduces both the mass and strength of concrete. This is true regardless of the temperature environment. Regardless of temperature, fire has a greater impact on chloride penetration in concrete. Though it was still higher than concrete mixed at ambient temperature, RMA concrete did better than the reference concrete mix. Limiting chloride penetration in the RMA concrete mixture depends critically on the alumina concentration of RMA

Structural Health Monitoring of Steel Girder Bridge Using Photogrammetry and LiDAR Scan Technology: Proof of Concept

Bridges require regular inspection and maintenance; however, traditional inspections are performed manually at prescribed intervals, involving substantial manpower, high costs, and safety risks due to the challenging locations of many bridges. To address these limitations, the present study focused on developing a methodology to automate technical inspections of bridges using a hybrid approach combining LiDAR and photogrammetry. Unlike past drone inspections, which were largely limited to basic photography and videography, this approach integrates advanced technologies for more comprehensive data collection. For this purpose, a single-span steel girder bridge with a span of 45.7 meters, located between Beas and tto Tanda in the state of Punjab, India, was selected. A Proof-of-Concept (PoC) was developed using high-fidelity digital models, created through photogrammetry with UAV-mounted high-resolution cameras and LiDAR, to carry out 16 inspection missions. The development of these high-fidelity digital models enabled flexible viewing, analysis, and measurement of various structural parameters, including the schedule of dimensions diagram, camber, distortions, rail levels, creep, and eccentricity. The parameters measured from the digital models were compared with the limiting values specified by RDSO, as well as with manually collected data. It was observed that the dimensional measurements obtained through the automated technology were within ±5 mm of the drawings and previous inspection reports, indicating that photogrammetry combined with LiDAR is a reliable and effective alternative technology for bridge inspection

An Examination of Reclaimed Asphalt Pavement's Role as Aggregate in the Composition of Structural Concrete: An Extensive Overview

The process of renovating flexible pavement produces an extensive amount of reclaimed asphalt pavement (RAP). These aggregates are frequently discarded, whether through legal or illegal means, in nearby locations, thereby creating various challenges for regulatory bodies. The incorporation of these aggregates into portland cement concrete (PCC) mixtures represents an innovative strategy that could yield significant socio-economic and environmental advantages. Nonetheless, the inclusion of RAP aggregates may also adversely impact both the soundness and performance characteristics of the concrete. This paper delivers a detailed and critical evaluation of the practicality of employing RAP aggregates in concrete production, while also pinpointing several shortcomings that must be rectified to enhance sustainability in construction methodologies. This paper is structured in the following manner: it initiates with a detailed characterization of RAP aggregates, followed by an analysis of the characteristics of fresh concrete containing RAP, and culminates in an exploration of RAP containing concrete mechanical and durability characteristics. According to the literature review, it is evident that aggregates derived from RAP are generally of a lower quality than their natural counterparts. This may not pose a significant issue regarding the characteristics of the fresh concrete. The asphalt film and the presence of agglomerated particles within the RAP were identified as key factors contributing to the diminished strength and durability characteristics. The integration of RAP as aggregates has been associated with notable advantages, including improved toughness. Furthermore, existing research suggests that the performance of concrete containing RAP can be enhanced through the processing of RAP in conjunction with using supplementary cementitious materials (SCMs) or fibres

Strengthening of Deficient Drop-in-ends with Near Surface Mounted (NSM) Steel Bars under static and repeated loading

The present research work, presented the results of eight drop-in-ends specimens tested experimentally to investigate the efficiency of the NSM steel bars technique in strengthening the drop-in-ends including internal miss detailing, under static and repeated loading. Two values of shear span/depth (a/d) ratios was considered, namely are 1.0 and 1.5. Several variables were considered including (a/d) ratio, effect of deficient nib reinforcement (by about 40%) and the type of loading. The behaviour has been discussed in terms of cracking load, failure load, cracking pattern, load-deflection curve and failure mode. Results revealed that increasing a/d ratio from 1.0 to 1.5 yielded a reduction in capacity and the corresponding deflection by 33% and 5%.Moreover, capacity reduced by 11% and 5% for the two values of a/d respectively, when the nib steel reduced by (40%).Furthermore, it was found that the strengthening by NSM steel bars resulted in increasing capacity by 15% and 14% for the two a/d ratio respectively. Regarding the repeated loading tests, it was found that capacity and corresponding deflection reduced by 25% and 42% for a/d =1.0 relative to the strengthened specimen and tested under static loading ,while the respective values for a/d =1.5 were 5% and 3%.  In addition, it was obtained that the capacity was reduced by 16% when increasing a/d ratio from 1.0 to 1.5

Experimental research on evaluation of the possibility of using crushed stone dust at Nghe An province-Viet Nam for reinforced concrete beams

In this paper, the use of crushed stone dust in Nghe An province is studied to replace natural sand in the production of concrete of compressive strength level B15. To evaluate the possibility of replacing part of natural sand in concrete with crushed stone dust according to the Vietnamese system of standards for designing reinforced concrete structures, the experimental study is analyzed based on experiments including: (i) Determining grain size, (ii) determining slump, (iii) compressing cube specimens to determine compressive strength, (vi) pulling out test to determine the bond force between steel and concrete, (v) bending compression of beam specimens of size 10×15×120 cm to failure. The initial research results show that the compressive strength at 28 days of cube concrete specimens using crushed stone dust exceeds 7,2-12,6% compared to concrete using natural sand. The beam sample using a small aggregate of 50% natural sand + 50% crushed stone dust has a greater load-bearing capacity than the reinforced concrete beam sample using 100% natural sand and is 6% larger

Real-Time and Full-Scale Numerical Analysis and Monitoring of Displacements in the Left Bank of the Tabellout RCC Arch Dam during Construction and Operation, Jijel Province, Algeria

This study provides a comprehensive evaluation of the Tabellout RCC dam in Jijel Province, Algeria, a unique structure classified as a combined gravity-arch dam. It addresses critical geotechnical, hydraulic and structural stability aspects, presenting significant contributions to the field of dam engineering by advancing the understanding of the interaction between RCC layers and adjacent slopes under operational conditions. This research employs real-time, full-scale numerical modelling using "Plaxis 2D," with a particular focus on arch behavior. The study bridges a gap by integrating hydrostatic and hydrodynamic pressures measured during the initial filling phase into the model, offering insights into the dam’s behavior under both static and dynamic conditions. Monitoring of RCC layers across three elevations prior to operation revealed minimal displacements, with a maximum recorded displacement of 1 mm in the critical interaction zone between the RCC and the left bank slope. Post-operation analysis demonstrated uniform deformation across elevations, with a negligible 1 mm variance, confirming the homogeneity of RCC stiffness—an essential factor for structural stability. The safety factor (FoS) analysis confirmed stability under static conditions, but highlighted vulnerabilities under seismic conditions, underscoring the need for enhanced resilience measures. This work extends findings from previous studies, particularly by validating the importance of a seismic belt at the foundation, through detailed numerical analysis and comparison with real-time monitoring data from PDL pendulums.