PRODUCTION OF LOW-COST SELF-CONSOLIDATING CONCRETE (SCC) USING MANUFACTURED AGGREGATES

Limitations to the sources of aggregates and the unavailability of sand is becoming a problematic issue for concrete production. A novel technology of manufactured aggregates can produce well graded round aggregates that can substitute natural aggregates while maintaining the same characteristics needed and preserving the resources. Self-Consolidating Concrete (SCC) using manufactured aggregates is assessed in this experimental work to understand the variability of workability properties and mechanical properties with the changes in w/c ratio and percentages of Coarse Aggregates and Manufactured Sand to Natural Sand in order to choose the best mixture that satisfies an adequate overall performance. Targeting compressive strength improvement, the SCC mixes included the use of Silica Fume (SF) and Polycarboxylate Superplasticizer which exhibited a strength improvement when compared to normal SCC. After performing 6 different trial mixtures, the use of manufactured rounded aggregates of percentages 73% from total fine aggregates proportion, 2.7% of Polycarboxylate superplasticizer, and around 8% Silica Fume (SF) from total cementitious materials can succeed in reaching high strength concrete with optimum mechanical properties and a noticeable workability improvement when compared to natural aggregates

Pregnancy and Neonatal Outcomes in SARS-CoV-2 Infection: A Systematic Review

With the emergence of SARS-CoV-2 and its rapid spread, concerns regarding its effects on pregnancy outcomes have been growing. We reviewed 245 pregnancies complicated by maternal SARS-CoV-2 infection across 48 studies listed on PubMed and MedRxiv. The most common clinical presentations were fever (55.9%), cough (36.3%), fatigue (11.4%), and dyspnea (12.7%). Only 4.1% of patients developed respiratory distress. Of all patients, 89.0% delivered via cesarean section (n=201), with a 33.3% rate of gestational complications, a 35.3% rate of preterm delivery, and a concerning 2.5% rate of stillbirth delivery or neonatal death. Among those tested, 6.45% of newborns were reported positive for SARS-CoV-2 infection. Relative to known viral infections, the prognosis for pregnant women with SARS-CoV-2 is good, even in the absence of specific antiviral treatment. However, neonates and acute patients, especially those with gestational or preexisting comorbidities, must be actively managed to prevent the severe outcomes being increasingly reported in the literature