The Influence of Nano-Silica on Some Properties of Light Weight Self-Compacting Concrete Aggregate

Lightweight concrete (LWC) has been used successfully in building constructions for many years due to its physical properties and its lightweight with high thermal insulation and durability. Recently, this work was done on a new type of concrete: lightweight self-compacting concrete (LWSCC) that combines the feature of lightweight and self-compacting concrete simultaneously. In this study, light expanded clay aggregate (LECA) was used as coarse aggregate in (LWSCC) mixtures, using nano-silica as a partial replacement of cement with three percent (0.5, 0.75, and 1%) by mass of cement. They were tested to evaluate these values of fresh characteristics through slump flow time and diameter, L-box, and segregation tests. The results of the fresh concrete tests showed a decrease in the workability of the concrete in the mixtures containing nano-silica due to the increase in fine materials in the mixture. The effects of nano-silica on the hardened properties of (LWSCC) such as compressive strength, flexural strength, splitting tensile strength, oven-dry density, and scanning electron microscopy (SEM), have improved. The mixtures containing nano-silica were investigated and compared with the reference mixture, where the results of the tests showed a significant improvement in the mechanical properties by (17.35, 16.27, 11.73, and 3.82%) for each of the compressive strength, flexural strength, splitting tensile strength and oven dry density respectively. In the presence of nano-silica, the replacement percentage of 1% recorded the best results in all tests at 90 days of curing

Effect of Silica Fume on Some Properties of No-Fine Concrete with Recycled Coarse Aggregate

No-fines Concrete is a lightweight porous concrete produced by omitting sand from the traditional concrete mix. It helps replenish the groundwater aquifer by directly allowing precipitation to seep into the earth thanks to its wide pores. This work studied the influence of partially replacing cement with silica fume (SF) with percentages of 5, 8, and 10% on some properties of no-fine concrete made using recycled coarse aggregate. The natural coarse aggregate (NA) was replaced with 10%, 20%, and 30% by crushed reactive powder concrete waste volume as recycled aggregate (RA). The optimum percentage was 10% RA with 10% SF, which indicated a substantial improvement in the no-fine concrete's strength, dry density, and water absorption compared to the design mix. The results exhibit increases in percentages in compressive strength, tensile strength, flexural strength, and dry density by 18%, 14%, 16%, and 1%, respectively, while exhibiting a decrease in water absorption by 5% at 28 days

Behavior of Steel-Fiber Reinforced Lightweight Self-Compacting Concrete Containing LECA after the Exposure to Internal Sulfate Attack

For many years, lightweight concretes (LWC) have been utilized successfully in the construction of buildings because of their low specific weight, high thermal insulation capacity, and sound insulation. The development that led to lightweight self-compacting concrete (LWSCC) is a significant step forward in recent years. These concrete chains self-compacting concrete's beneficial properties with lightweight concrete. The purpose of this experimental investigation is to determine how the internal sulfates attack effect fresh and hard properties of lightweight self-compacting concrete (LWSCC) made by using lightweight expanded clay aggregate (LECA) before and after the addition of 0.5 volume fraction (Vf) of steel fibers. In fine aggregate, several concrete mixes were cast in different SO3 percentages (0.34, 2, 4, and 6%). The fresh properties of LWSCC concrete were tested, such as (slump, sieve segregation resistance, and L-box test). The hard properties of LWSCC were (Compressive, splitting tensile strength, flexural strength, oven-dried density, and modules of elasticity). The results showed that the presence of SO3 in fine aggregate affects the properties of LWSCC. A significant decrease in fresh properties of LWSCC mixes with (2, 4, and 6%) of SO3 in fine aggregate. In addition, the mechanical properties (compressive St., splitting tensile St., flexural St., density, and modulus of elasticity) decreased as curing age increased, and SO3% increased. When sulfate percent rose from (0.34% to 2%, 4%, and 6%) in compressive St., the reduction was (16.53, 22.45, and 26.47%) at 120 days. Adding 0.5% Vf of steel fiber enhanced the mechanical properties of LWSCC

Effect of Perlite Aggregate Replacement of Coarse Aggregate on the Behavior of SCC Exposed to Fire Flame by Using Different Cooling Methods

The qualities of both fresh and hardened perlite self-compacting concrete are assessed in this study. The self-compacting concrete mix utilized in this investigation included 594 kg/m3 of binder. Four concrete mixes were tested with perlite used in place of some of the coarse aggregate at volumetric ratios of (0, 20, 40, and 50) %. Slump flow, V-funnel, L-Box, and segregation index tests were used to evaluate the properties of fresh concrete. At 56 days after burning, hardened concrete is tested. These tests gauge a material's flexural, splitting, and compressive strengths. According to the data perlite content reduces workability. The percentage of perlite increases causes a considerable decrease in the compressive, flexural, and splitting tensile strengths when compared to the reference mixture. Following their burning at (300, 500, and 700 °C), half of the specimens cooled gradually before being tested, while the other half cooled rapidly. The residual percentages of Compressive strength at 56 days after burning were the most at 50% perlite, with (89.75,65.21, and 42.86) % at 300, 500, and 700 Co, respectively for gradual cooling. The residual percentages of Splitting tensile strength at 56 days after burning for PG50% were (98.85,85.22and 51.31) % at 300, 500, and 700 Co, respectively for gradual cooling

The Influence of Polypropylene Fiber and Silica Fume on the Mechanical Properties of No-Fine Concrete with Recycled Aggregate

No-Fines Concrete is a type of concrete produced without fine aggregate or sand. Because of its high porosity, it allows rainwater to seep into the ground, directly replenishing the groundwater aquifer. With a design load of three tons, no-fine concrete can be utilized as pavement for rural roads. Additionally, this type of concrete can be utilized as a sub-base material in both flexible and rigid pavements. Aside from No-Fines Concrete's permeability properties, asphalt overlays are another option. This research studied the impact of silica fume and polypropylene fiber on the properties of no-fine concrete with recycled aggregate. The ratios of cement to aggregate and water to cement were 1:4 and 0.3, respectively. The recycled aggregate was demolished reactive powder concrete used in percentages of 10, 20, and 30% as a substitution for coarse aggregate by volume. The recycled aggregate percentage of 10% was the optimal percentage as it showed the least adverse effect on the no-fine concrete mixes. The polypropylene fiber was then added to the no-fine concrete mixes with 10% recycled aggregate in the percentages of 0.5, 1, and 1.5% by volume. The optimum percentage of polypropylene fiber was 0.5%, which improved the mechanical properties of no-fine concrete. Silica fume was used as a partial substitution for cement at a percentage of 10% and added to no-fine concrete mix with 10% recycled aggregate. The results show that using 10% silica fume and 0.5% polypropylene fiber with 10% recycled aggregate increased the splitting tensile strength, flexural strength, compressive strength, and modulus of elasticity by (22.54 and 40.32%), (22.22 and 35%), (21 and 35.37%), and (22 and 38.19%) compared to reference mix (NC) and the no-fine concrete mix with 10% recycled aggregate (RNC10), respectively. In comparison, the dry density was higher by (1.34%) than RNC10 and lower by (0.68%) than NC

Investigating Some Properties of Hybrid Fiber Reinforced LECA Lightweight Self-Compacting Concrete

. The primary goal of this investigation is to study the effect of using mono and hybrid fibers on the fresh and hardened characteristics of Lightweight Self-Compacting Concrete (LWSCC). Slump flow test, L-box test, sieve segregation test, and V-funnel test were used to evaluate the workability of LWSCC. The mechanical characteristics of LWSCC were assessed by using compressive strength, splitting strength, and flexural strength. Four mixtures using two types of fiber: Steel fiber (St) and polypropylene fiber (PP) (0% fiber, 1% (St), 0.75% (St) +0.25% (PP), 0.5% (St) +0.5% (PP)) were made. According to the results, (St) fiber and hybrid fiber addition to LWSCC reduced its workability, although the values of tests were still within the acceptable range stander of EFNARC. The findings indicated a decrease in the values of slump flow and L-box test by adding mono and hybrid fibers to the LWSCC mixture. While the T500mm and V_ funnel tests increased by adding mono and hybrid fibers to LWSCC mixture. The results also indicate that the utilisation of (St) fiber and hybrid fibers had a significant effect on the mechanical characteristics of LWSCC. Where the flexural and splitting strengths significantly increase with the addition of (St) and hybrid fibers to the LWSCC mix

Collocational knowledge in children: a comparison of English-speaking monolingual children, and children acquiring English as an Additional Language

Collocations, e.g., apples and pears, hard worker, constitute an important avenue of linguistic enquiry straddling both grammar and the lexicon. They are sensitive to language experience, with adult L2 learners and children learning English as an Additional Language (EAL) exhibiting poor collocational knowledge. The current study piloted a novel collocational assessment with children (mean age 6;3, 40 monolingual, 32 EAL). It investigated (1) the feasibility of a collocational assessment at this age, (2) whether collocational knowledge is associated with other language domains (receptive grammar and vocabulary), and (3) whether collocational knowledge is more affected than other domains. The assessment demonstrated good psychometric properties and was highly correlated with performance in other domains, indicating shared psycholinguistic mechanisms. Unlike adult counterparts, the EAL children performed equally poorly across domains. Given the role played by collocations in vocabulary development and reading, a focus on this domain may be beneficial for EAL children

Improving the Properties of Gypsum By Using Additives

Gypsum Plaster is an important building materials, and because of the availabilty of its raw materials. In this research the effect of various additives on the properties of plaster was studied , like Polyvinyl Acetate, Furfural, Fumed Silica at different rate of addition and two types of fibers, Carbon Fiber and Polypropylene Fiber to the plaster at a different volumetric rate. It was found that after analysis of the results the use of Furfural as an additive to plaster by 2.5% is the optimum ratio of addition to that it improved the flexural Strength by 3.18%. When using Polyvinyl Acetate it was found that the ratio of the additive 2% is the optimum ratio of addition to the plaster, because it improved the value of the flexural strength by a rate of 3.44% of the value of standards fraction of the mixture of reference. It was noted that the optimum ratio for the addition of Fumed Silica to the plaster is the ratio of 1%, because this ratio of addition increases the flexural strength by 15.26%. For the addition of Carbon Fiber to the plaster it was found that the volumetric ratio of the additive 0.5% is the percentage of perfect accessory after taking into account cost and quality which gives an increase in Flexural Strength by rate of 41.43% .When using Polypropylene Fiber it was found that the optimum percentage ratio of addition 1.5%, where this ratio increases flexural strength by a rate of 23.67% . When using the mixture (PVCF), which contains 2% of Poly vinyl Acetate and 0.5% as a volumetric rate of the carbon fiber to the plaster, increases the value of Flexural Strength by a rate 62.92%. After analyzing the results for all mixtures it was found that the mixture (PVCF) is the best one to satisfy the aim of the research which is to get the best structural properties specially flexural strength for gypsum beams

STUDY OF VITAMIN B12 DEFICIENCY AND ITS RELATION WITH METFORMIN TREATMENT AMONG DIABETICS IN PRINCE RASHID HOSPITAL

Introduction: Vitamin B12 has important functions in physiology and pathology of human body. It can help against diseases through improving immune system. The role of Its deficiency with metformin treatment is still subjecting to diabetes. Objectives: 1. To investigate the prevalence of Vitamin B12 deficiency among diabetics visiting internal medicine clinics in Prince Rashid Hospital. 2. To explore the association of Vitamin B12 deficiency with metformin treatment among the same sample. Methods and subjects, Study design: A retrospective design was employed to collect data from files of diabetic patients. Study sample: A total of 447 files of diabetic patients were accessed if inclusion criteria were met. Inclusion criteria: Diabetic patient. Vitamin B12 status is mentioned. Metformin treatment is recorded in files of diabetic patients. Data collection: data will be collected for each patient and entered into excel sheet for further analysis. Statistical analysis: SPSS version 20 was used for data analysis. Data was presented as frequency and percentage for numerical variables, whereas the association between variables was tested using Chi- Square test. Significance was tested at alpha level < 0.05. Results: The prevalence of vitamin B12 deficiency was 7.2%. The mean age of study participants was 55.70+10.13 years. Metformin intake was reported by approximately 84% of diabetics. About 76% of participants had cardiac diseases. No significant association was observed between metformin and vitamin B12 deficiency (p=0.269). Conclusion: The prevalence of vitamin B12 deficiency among diabetics was 7.2%. No significant association was observed between treating diabetics with metformin and vitamin B12 deficiency. Recommendation: Lacking the association between treatment of metformin and vitamin B12 deficiency may due to small participants included in other studies, and we recommend to include larger numbers of participants in future studies

Assessment of Albumin Usage Patterns and Appropriateness in a Comprehensive Cancer Centre: A retrospective study in Jordan

Objectives: Albumin is commonly used for various indications; however, there is conflicting data regarding its appropriate use in different clinical cases. This study aimed to determine the pattern and appropriateness of albumin use among cancer patients at the King Hussein Cancer Center in Jordan. Methods: A retrospective analysis was conducted on adult cancer patients who were prescribed albumin between January 2019 and July 2020 in both outpatient and inpatient settings. Data collected included demographics, prescribing services, indications and dosing regimens. A literature review was performed using PubMed to assess the appropriateness of albumin indications and dosing regimens against current guidelines, drug information resources and the package insert. Results: Albumin was prescribed to 1,361 patients during the study period. Each patient received an average of 74.4 ± 89 g of albumin for an average of 2.6 ± 1.8 days. Albumin use was deemed appropriate in 69% of the patients. The critical care service accounted for the highest albumin consumption, with 37% of prescriptions for septic shock. Inappropriate use of albumin was most prevalent in the medical solid tumour services (40.8% of prescriptions), primarily for edema (28%). Conclusion: To the best of the author’s knowledge, this study is the first to evaluate albumin use in a large cohort of oncology patients. Approximately one-third of the albumin prescriptions were considered inappropriate. Continuous education on appropriate usage and regular evaluations of guideline adherence are essential to ensure proper utilisation of albumin in cancer care