Mechanical Properties of High Performance Carbon Fiber Concrete

In this research mechanical properties of high performance carbon fiber concrete are studied. The experimental work includes, producing high performance concrete using superplasticizer and condensed silica fume reinforced with different volume fractions (0%, 0.2%, 0.3%, 0.4% and 0.5%) of carbon fibers. The effect of chopped carbon fibers on the mechanical properties (compressive strength, splitting tensile and flexural strengths, and modulus of elasticity) of high performance concrete was also studied. Generally, the results show that the addition of carbon fibers improves the mechanical properties of high performance concrete. Also the results show that Using condensed silica fume as addition by weight of cement increases the compressive strength more than that as replacement by weight of cement. The percentages increase in compressive strength of concrete containing 15% silica fume as replacement and as addition by weight of cement are about 14% and 26% respectively. The addition of carbon fibers causes a slight increase in compressive strength and modulus of elasticity of high performance concrete when the fiber volume fraction increases, while the splitting tensile and flexural strengths shows a significant increase relative to the reference high performance concrete (without fiber). The percentage increase in splitting tensile and flexural strengths for high performance concrete with fiber volume fraction 0.5% at 28 days is about 45% and 46% respectively

FLEXURAL STRENGTH OF FIBROUS ULTRA HIGH PERFORMANCE REINFORCED CONCRETE BEAMS

ABSTRACT The flexural behavior of eleven 150×150×1950 mm ultra high performance conventionally reinforced concrete beams containing hooked and crimped steel fibers with different volume fractions (0.5%, 0.75% and 1%) in full and partial depths of beams cross sections is studied in this investigation. The load deflection relationship, resilience, toughness indices, first crack load, ultimate load and concrete strains were investigated. The experimental results show that the addition of steel fibers slightly enhances the load-deflection relationship and ultimate load for beam specimens. The type of steel fibers (crimped and hooked) has a little effect on load-deflection behavior, ultimate moment capacity, cracking pattern, while in resilience and toughness, beam specimens with hooked steel fiber showed slightly better behavior than those with crimped steel fibers. The ultimate tensile strength of beams has been rederived and contributed in order to calculate the moment capacity. The calculated ultimate moment capacity was in good agreement with the experimental ultimate moment capacity

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

ENGINEERING PROPERTIES OF SUSTAINABLE SELF-COMPACTING CONCRETE WITH CLAY BRICKS WASTE AGGREGATE

The present study covers the use of different percentages (25, 50, 75 and 100%) of clay bricks waste as replacement by volume of coarse natural aggregates to produce sustainable self-compacted concrete (SCC). All mixes used containing 10% silica fume as a replacement by cement weight. The properties of SCC studied were, workability, fresh density, dry density, water absorption, compressive strength, splitting tensile strength, flexural strength, modules of elasticity and thermal conductivity. The results show that the flow ability, filing ability, and passing ability of self -compacted concrete through steel reinforcement are decrease with the increase of clay brick waste content. In addition, the segregation resistance decreases with the increase of clay brick waste content of SCC. The use of clay brick waste aggregate causes reduction in density, compressive strength, splitting tensile strength, flexural strength, modules of elasticity and thermal conductivity of SCC. The percentage reduction increases with the increase of clay bricks waste content in self-compacted concrete.http://dx.doi.org/10.30572/2018/kje/09031

PROPERTIES OF HIGH STRENGTH ECO-FRIENDLY CONCRETE WITH GLASS WASTE POWDER

This investigation includes the use of glass wastes after recycling to produce High Strength Eco- Friendly Concrete. The glass waste was collected, crushed, and grinded for 10 minutes to produce a powder with fineness higher than that for cement of about 7340 cm2/gm. Many tests were conducted on this powder including, chemical analysis, pozzolanic activity index tests, and the remaining content on sieve of 45 microns. The results show that the glass waste powder considered as a natural Pozzolan class (N) according to ASTMC618. Many concrete mixes with different percentages of glass waste powder as a partial replacement to cement (10%, 15%, 20%, 25%, and 30%) were prepared. The properties of concrete (fresh density, compressive strength at 7, 28, 60, and 90 days age, and water absorption at 60 days age)were studied and compared with the results of the reference concrete mix (without glass powder). The compressive strength for concrete specimens with 10%, 15% glass powder content at 28, and 60 days age is increased. When the content of glass powder is increased to 20%, 25%, and 30%, the compressive strength is decreased compared with the reference concrete specimens. The highest percentages increase in compressive strength are 1.17%, 13.3%, 19.34% for specimens with 15% glass powder at 28, 60 and 90 days age respectively, while the water absorption is decreased. Keywords: High strength concrete, Sustainable concrete, Glass waste powder, Green concrete, Eco- friendly concrete

SOME PROPERTIES OF ECO-FRIENDLY SELF-COMPACTED CONCRETE WITH PLASTIC WASTE AGGREGATE

This studying including the using of plastic wastes after recycles to produce Eco- Friendly self-compacted Concrete, all these wastes lead to environmental pollution, because the plastic waste isnon-biodegradable solid waste, which arefound at waste disposal areas in Iraq.The present study covers the using wastesof plastic as volumetric replacement to coarse natural aggregates to produce eco-friendly self-compacted concrete. Four self-compacting concrete (SCC) mixes were prepared containing different percentages (25, 50, 75 and 100%) of plastic wastes as a volumetric replacement tocoarsenatural aggregate. In addition to reference self-compacted concrete mix (without plastic waste aggregate).Also, 10% silica fume as a replacement by cement weight was used for each concrete mix. The properties of self-compacted concrete including, workability, fresh density, dry density, compressive strength, splitting tensile strength, and flexural strength were investigated. The results shows that the implication wasteofplastic aggregate causes an increase in flow ability, filing ability, and passing ability of self-compacted concrete through steel reinforcement. Segregation resistance decreases with the increasing of plastic waste content. Also, the results show that the implicationwaste of plastic waste aggregate causes a reduction in density, compressive strength, splitting tensile strength, and flexural strength. The percentage reduction increases with the increasingwaste of plastic waste content in self-compacted concret