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Author(s): Kirit Arumalla [1]; Akshay Kulkarni [1]; Nishanth Sadashiva [1]; Subhas Konar [1]; Gyani Jail Singh [1]; Nanjundaiah Gopalakrishna [2]; Jitender Saini [3]; Mohammad Nadeem [1]; Dhaval Shukla [1]; Bhagavatula [...], Introduction: Unintentional falls from height are a major cause of pediatric traumatic injury. This retrospective study investigated the characteristics, clinic-radiological features, and associated outcomes in a tertiary referral neurosurgical center. Materials and Methods: This study is a retrospective review of children below 16 years who presented to our neurosurgery referral center from January 2018 to 2019 with a history of fall from height. The demographic data, clinical parameters at presentation, imaging findings, clinical status at discharge, and outcome at the follow-up period were analyzed. Results: Of the 1,310 children with a history of neurotrauma, 520 (39.7%) of them had a history of fall from height, among which 67% were falls from short height. The mean age was 5.99 ± 4.9 years. Of these 82.8% of children had mild, 13.8% moderate, and 3.2% had severe head injury. The imaging findings were normal in 59%, subgaleal hematoma in 18.6%, extradural hematoma in 9.9%, and spinal injuries in 1.4%. The regression analysis showed age, gender, the height of the fall, loss of consciousness, and seizure as predictors of the severity of the head injury. The Median Glasgow Outcome Scale-Extended at the follow-up period was one. About 2.3% of children had mortality within 1 week after the injury. The midline shift and associated injury had a significant impact on the outcome. Conclusion: In our retrospective study age, gender, height of fall, loss of consciousness, and seizures were associated with the severity of head injury. The presence of midline shift and other associated injuries was associated with the outcome at follow-up. Keywords: Fall from height, glasgow outcome scale, pediatric head injury, severe head injury

In current era, construction activities are essential for modern civilization. Steel, concrete, wood, and glass are key materials for construction. Among all, concrete is further gaining rapid recognition due to its inherent properties. However, making of concrete involves use of natural resources, which is a growing concern over the depletion of natural resources in construction. Owing to that need of sustainable alternatives such as RCA are gaining attention very rapidly. Current study examines the strength and durability aspects of HSC using unprocessed and processed RCA. The mechanical properties of concrete were evaluated in a three-stage analysis, comparing mixes made with natural aggregates, unprocessed RCA, and processed RCA. The processing of RCA involved mechanical grinding, optimized through Abrasion, with replacement levels of 25% and 50%.The compressive strength results indicated that a 25% replacement of natural aggregates with processed RCA achieved the target strength, outperforming concrete with unprocessed RCA but remaining lower than natural aggregate mixes. Tests, including Rapid Chloride Penetration Test, Ultrasonic Pulse Velocity, and Sorptivity, were conducted to assess the long-term performance. Processed RCA at 25% replacement exhibited improved durability, with lower chloride ion permeability, higher UPV values indicating better homogeneity, and reduced sorptivity, reflecting enhanced resistance to moisture ingress. These findings highlight that processed RCA offers a viable solution for sustainable concrete production, with strength and durability characteristics comparable to traditional materials at lower replacement levels.

Present research critically investigates drying sensitivity and cement hydration resumption in recycled aggregate concrete (RAC). To determine minimum post-curing time for optimum strength resumption in RAC, a curing ratio (δ) is introduced. Curing ratio is defined as the ratio between post-curing duration and delay time before curing. Drying sensitivity of RAC is observed significantly lower than NAC. The maximum strength loss under drying conditions is 25.9% in RAC (OPC) and 23.2% in RAC (PPC). Strength criteria determine the curing ratios of RAC (OPC) and RAC (PPC) as 2.22 and 0.30. The maximum delay time for RAC (OPC) and RAC (PPC) is determined at 8 days and 21 days with a minimum post-curing for 17.76 and 6.63 days. The longest allowable delay produces ion penetration less than 1000 Coulombs, resistivity greater than 208 ohm-m, superior structural integrity and internal compactness, and sorptivity comparable to RACs cured after a shorter delay. [ABSTRACT FROM AUTHOR]

This study demonstrates an integrated thermomechanical treatment process to produce high quality recycled concrete aggregate (RCA) for structural concrete. RCA is mechanically treated after 90 min of heating at 250 °C in this process. The material properties of RCA produced through 15 combinations of charges and drum revolutions are compared using a statistical method. The highest ranking of an RCA identifies it as a high-quality class. Concrete composed of 100% RCA (recycled aggregate concrete, RAC) has 1.7% higher compressive strength than natural aggregate concrete (NAC). RAC has tensile and flexural strengths of 0.95 and 1.03 in fraction of NAC. RAC meets durability criteria such as UPV greater than 4.4 km/s, rapid chloride ion penetration test (RCPT) less than 1000 C, electrical resistivity greater than 208 Ohm-m, and sorptivity closer to NAC. Water absorption and abrasion resistance are similar to or superior to those of NAC. Coherent and uniform surface morphology of RCA enhances the ITZ microstructure in RAC. [ABSTRACT FROM AUTHOR]

This study outlines a method for identifying high-quality recycled concrete aggregate (RCA) obtained after mechanical treatment. In the present approach, the physical and mechanical properties of RCA are considered as quality parameters. As a first step, mechanically treated (Los Angeles) RCA is produced with 28 combinations of charges and drum revolutions. Twenty-eight sets of mechanically treated RCA are produced, each with different physical and mechanical properties. Furthermore, the 28 sets of RCAs are compared using the performance-based quality optimization approach. The performance index for each set of RCAs is calculated applying a multicriteria decision-making approach named "technique for order of preference by similarity to ideal solution." This approach considers physical and mechanical properties as a response and the combination of charges and drum revolutions as alternatives to obtain the performance index of alternatives. Based on its performance, the leading rankings RCAs are selected for an experimental study to validate the methodology. As a result of RCA's optimized quality, recycled aggregate concrete (RAC) has excellent physical, mechanical, and durability characteristics that agree with natural aggregate concrete (NAC) composed of parent aggregate. The 28- and 91-day compressive strengths of RAC exceed those of NAC by 8.5% and 30.65%, respectively. Flexural strength, split tensile strength, fracture energy, ultrasonic pulse velocity (UPV) values, rapid chloride-ion penetration test values, water absorption, and abrasion resistance are comparable with NAC. The quality optimization approach identifies RCA with superior shape, texture, and elastic properties. An RCA with optimized qualities also strengthens the new interfacial transition zone and old interfacial transition zone as well as RAC's associated properties. The RAC's dynamic modulus of elasticity is superior to the reported values and is 0.95 fractions of NAC. Optimized quality of RCA reduces the sorptivity of RAC compared with the reported values. The RAC may not have equivalent sorptivity to NAC without lowering RCA parts, whether mortar-attached, mortar-covered, or mortar-only type aggregate or applying other treatments that may increase the production cost. This research presents a standard procedure for identifying mechanically treated recycled concrete aggregate with properties (physical properties and mechanical properties) similar to those of the parent aggregate (natural aggregate). The method demonstrated in this study may be adapted to real-life worksite conditions—but not exactly. In Los Angeles abrasion machines, recycled concrete aggregates obtained from a source can be processed by varying drum revolutions and charges. Based on the charges and drum revolutions selected for treatment, treated recycled concrete aggregate can be prepared with different sets of physical and mechanical properties. Based on the present research, the physical and mechanical properties of treated recycled concrete aggregate can be compared between these sets. In this way, recycled concrete aggregates can be produced that resemble their parent aggregates. Using this process, recycled concrete aggregates may be used to replace natural aggregates without compromising the concrete's physical, mechanical, or durability properties. [ABSTRACT FROM AUTHOR]