scholarly journals Effect of corrosion on the bond strength of self consolidated lightweight concrete

2021 ◽  
Author(s):  
Tariq Mumtaz
Keyword(s):  
Failure Modes ◽  
Lightweight Concrete ◽  
Strength Properties ◽  
Seismic Zone ◽  
Time Data ◽  
Voltage Versus ◽  
Accelerated Corrosion ◽  
Filling Ability ◽  
Expanded Shale ◽  
Passing Ability

Self-consolidating lightweight concrete (SCLWC) is a concrete with excellent filling ability, good passing ability, and adequate segregation resistance. The use of SCLWC can be beneficial for structures due to significant reduction in dead loads as well as structures in seismic zone. In addition, economic impacts on construction industry by using SCLWC will be significant because of its benefits. Three SCLWC mixtures are developed by using two types of lightweight aggregates (LWA) (such as blast furnace slag and expanded shale), two supplementary cementing materials (such as fly ash and metakaolin). In addition to fresh and strength properties, the effect of different degrees of accelerated corrosion on bond characterists of deformed steel bars in SCLWC is investigated by analyzing pullout test results such as load-slip relationship, voltage versus time data, failure modes, aggregate of specimens and concrete material characteristics.

scholarly journals Effect of corrosion on the bond strength of self consolidated lightweight concrete

2021 ◽  
Author(s):  
Tariq Mumtaz
Keyword(s):  
Failure Modes ◽  
Lightweight Concrete ◽  
Strength Properties ◽  
Seismic Zone ◽  
Time Data ◽  
Voltage Versus ◽  
Accelerated Corrosion ◽  
Filling Ability ◽  
Expanded Shale ◽  
Passing Ability

Self-consolidating lightweight concrete (SCLWC) is a concrete with excellent filling ability, good passing ability, and adequate segregation resistance. The use of SCLWC can be beneficial for structures due to significant reduction in dead loads as well as structures in seismic zone. In addition, economic impacts on construction industry by using SCLWC will be significant because of its benefits. Three SCLWC mixtures are developed by using two types of lightweight aggregates (LWA) (such as blast furnace slag and expanded shale), two supplementary cementing materials (such as fly ash and metakaolin). In addition to fresh and strength properties, the effect of different degrees of accelerated corrosion on bond characterists of deformed steel bars in SCLWC is investigated by analyzing pullout test results such as load-slip relationship, voltage versus time data, failure modes, aggregate of specimens and concrete material characteristics.

scholarly journals Enhancing the Strength Properties of Self-Compacting Concrete with Fiber Reinforcement

2019 ◽  
Vol 6 (5) ◽  
pp. 5-8
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Strength Properties ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Filling Ability ◽  
Hardened Properties ◽  
Passing Ability ◽  
New Generation

Self-compacting concrete is one that is flow able by its own. The SCC is suitable for placing in dense reinforcement structures. It is a new generation performance concrete known for its outstanding deformity and high resistance to bleeding. The concrete is frail material which is comparatively tough in compression but fragile in tension. The tensile strength of concrete is improved by addition of fibers in the concrete mix. The addition of such fibers has negative consequence on the workability of concrete. Various types of fibers are used in concrete to provide the higher flexural strength and better tensile strength. In this research steel fibers are used to provide a better strength as compared with normal reinforced concrete. Steel fiber in SCC significantly improves its flexural strength, improved tensile properties, reduce cracking and improve durability. In this research the investigation of steel fiber in SCC to enhance the strength properties of SCC. The objective of the study was to determine different properties of SCC with steel fiber at different proportions. The experimental investigation was took on the freshly mixed and hardened properties of SCC of various mix with the different variations of fiber 0.25%, 0.50%, 0.75% and 1% by using Viscosity Modified Agent (VMA) 1.5% of cement material by using M25 grade of concrete. In this research a series of tests were carried out for workability like slump cone test, U funnel, V funnel, L box test on SCC to check freshly mix properties like flow-ability, filling-ability, and passing-ability and hardened properties like compressive strength, split-tensile strength and flexural strength respectively and test were conducted at the age of 7Days, 14Days, 28Days on the SCC. The advantage of adding steel fiber in self-compacting concrete is that it enhances its overall strength.

Utilization of Iron Filings as Partial Replacements for Sand in Self-Compacting Concrete

2021 ◽  
Vol 47 (3) ◽  
pp. 906-916
Author(s):  
Simon O. Olawale ◽  
Mutiu A. Kareem ◽  
Habeeb T. Muritala ◽  
Abiola U. Adebanjo ◽  
Olusegun O. Alabi ◽  
...  
Keyword(s):  
Steel Production ◽  
Strength Properties ◽  
Self Compacting Concrete ◽  
River Sand ◽  
Slump Flow ◽  
Filling Ability ◽  
Fine Aggregates ◽  
Concrete Production ◽  
Fresh State ◽  
Passing Ability

The use of industrial by-products in concrete production is part of concerted efforts on the reduction of environmental hazards attributed to the mining of conventional aggregates. Consideration of iron filings (IF), a by-product from steel production process, is an environmentally friendly way of its disposal which is expected to yield economic concrete production. Six self-compacting concrete (SCC) mixes were made by partially substituting river sand with IF at 5%, 10%, 15%, and 20% and the mix without IF (0% IF) served as the control. The water-binder (w/b) ratio of 0.45 was adopted for all mixes. The fresh state properties of SCC evaluated include: filling ability determined using slump flow and T500 mm slump flow tests, passing ability determined using L-box test and segregation resistance determined using V-funnel tests. The strength properties of SCC considered were compressive and tensile strengths. All the SCC mixes met the fresh properties requirements for filling capacity, passing ability, and segregation resistance. The 28-day compressive and tensile strengths of SCC increased by 3.46% and 8.08%, respectively, with IF replacement up to 15% compared to the control SCC. However, there was reduction in compressive and tensile strengths of SCC with IF replacement beyond 15%. The strength properties of SCC is considerably enhanced with the addition of up to 15% IF. Hence, the optimum content of 15% IF is considered suitable as a replacement for river sand in SCC. Keywords: Self-compacting concrete; iron filings; fine aggregates; filling ability; passing ability

scholarly journals Effects of Induction-Furnace Slag on Strength Properties of Self-Compacting Concrete

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Oluwaseun Mark ◽  
Anthony Ede ◽  
Chinwuba Arum ◽  
Solomon Oyebisi
Keyword(s):  
Induction Furnace ◽  
Strength Properties ◽  
Fresh Properties ◽  
Empirical Correlations ◽  
Self Compacting Concrete ◽  
X Ray ◽  
Slump Flow ◽  
Filling Ability ◽  
Passing Ability ◽  
Furnace Slag

Abstract Indiscriminate waste disposal poses a severe environmental challenge globally. Recycling of industrial wastes for concrete production is currently the utmost effective way of managing wastes for a cleaner environment and sustainable products. This study investigates the strength characteristics of self-compacting concrete (SCC) containing induction furnace slag (IFS) as a supplementary cementitious material (SCM). The materials utilized include 42.5R Portland cement, induction furnace slag as an SCM ranging from 0 to 50 % by cement weight at 10 % interval, river sand, granite, water and superplasticizer. The fresh properties were tested for filling ability, passing ability and segregation resistance, the strength characteristics measured include compressive strength, splitting tensile strength, flexural strength and Schmidt/rebound number. The oxide compositions and microstructural analysis of SCC were investigated using x-ray fluorescence analyser (XRF) and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (SEM-EDS), respectively. Empirical correlations were statistically analyzed using MS-Excel tool. The filling ability characteristic was determined via both the slump flow test and the T50cm slump flow time test. Moreover, the passing ability characteristic was determined using L-Box test. The segregation resistance characteristic was determined using V-funnel at T5minutes test. The results of the fresh properties showed a reduction in the slump flow with increasing IFS content. On the other hand, the T50cm slump flow increased with increasing IFS content. Furthermore, the L-Box decreased with higher IFS content. On the contrary, the V-funnel at T5minutes increased considerably with greater IFS content. The strength test results revealed that the strength properties increased to 20 % IFS, with a value of 66.79 N/mm2 compressive strength at 56 days, giving a rise of 12.61 % over the control. The SCC microstructural examinations revealed the amorphous and better interface structures with increasing IFS content in the mix. The empirical correlations revealed that linear relationships exist among the measured responses (fresh and strength properties). Ultimately, IFS could be utilized as a sustainable material in producing self-compacting concrete.

scholarly journals Effect of Steel Fiber Content on Shear Behavior of Reinforced Expanded-Shale Lightweight Concrete Beams with Stirrups

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1107
Author(s):  
Changyong Li ◽  
Minglei Zhao ◽  
Xiaoyan Zhang ◽  
Jie Li ◽  
Xiaoke Li ◽  
...  
Keyword(s):  
Crack Width ◽  
Failure Modes ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Shear Crack ◽  
Shear Capacity ◽  
Shear Cracks ◽  
Shear Cracking ◽  
Expanded Shale

To determine the validity of steel fiber reinforced expanded-shale lightweight concrete (SFRELC) applied in structures, the shear behavior of SFRELC structural components needs to be understood. In this paper, four-point bending tests were carried out on reinforced SFRELC beams with stirrups and a varying volume fraction of steel fiber from 0.4% to 1.6%. The shear cracking force, shear crack width and distribution pattern, mid-span deflection, and failure modes of test beams were recorded. Results indicate that the shear failure modes of reinforced SFRELC beams with stirrups were modified from brittle to ductile and could be transferred to the flexure mode with the increasing volume fraction of steel fiber. The coupling of steel fibers with stirrups contributed to the shear cracking force and the shear capacity provided by the SFRELC, and it improved the distribution of shear cracks. At the limit loading level of beams in building structures at serviceability, the maximum width of shear cracks could be controlled within 0.3 mm and 0.2 mm with the volume fraction of steel fiber increased from 0.4% to 0.8%. Finally, the formulas are proposed for the prediction of shear-cracking force, shear crack width, and shear capacity of reinforced SFRELC beams with stirrups.

scholarly journals Study on Adaptability of Test Methods for Workability of Fresh Self-Compacting SFRC

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5312
Author(s):  
Xinxin Ding ◽  
Haibin Geng ◽  
Kang Shi ◽  
Li Song ◽  
Shangyu Li ◽  
...  
Keyword(s):  
Steel Fiber ◽  
Volume Fraction ◽  
Test Methods ◽  
Fiber Reinforced Concrete ◽  
Ring Test ◽  
Steel Fiber Reinforced Concrete ◽  
Slump Flow ◽  
Filling Ability ◽  
Flow Test ◽  
Passing Ability

To ensure the quality of concrete construction, the workability of fresh mix measured by rational test methods is critical to be controlled. With the presence of steel fibers, whether the test methods and evaluation indices of fresh self-compacting concrete (SCC) are adaptable for self-compacting steel fiber reinforced concrete (SFRC) needs to be systematically verified. In this paper, seven groups of self-compacting SFRC, referenced with one group SCC, were prepared by using the mix proportion design method based on the steel fiber-aggregates skeleton packing test. The main factors included the volume fraction and the length of hooked-end steel fiber. Tests for filling ability, passing ability, and stability of fresh self-compacting SFRC and SCC were carried out. Results indicate that the adaptability was well for the slump-flow test with indices of slump flow and flow time T500 to evaluate the filling ability, the J-ring flow test with an index of PA level to evaluate the passing ability, and the static segregation test with an index of static segregation resistance to evaluate the stability of fresh self-compacting SFRC. By the repeated tests and measurements, the slump cone should be vertically lifted off to a height of 300 mm within 3 s at a constant speed, the spacing of the rebar in the J-ring test should be adjusted to be two times the fiber length. If the table jumping test is used, the dynamic segregation percent should be increased to 35% to fit the result of the static segregation test. Good workability of the self-compacting SFRC prepared in this study is presented with the general evaluation of test results.

Rehabilitation of Corrosion-Damaged Substandard RC Columns Using FRP Sheets

2013 ◽  
Vol 639-640 ◽  
pp. 1096-1103 ◽  
Author(s):  
Aras Kalyoncuoglu ◽  
Pooya Ghaffari ◽  
Caglar Goksu ◽  
Alper Ilki
Keyword(s):  
Failure Modes ◽  
Effective Cross Section ◽  
Lateral Loads ◽  
Reinforcing Bars ◽  
Rc Columns ◽  
Accelerated Corrosion ◽  
Drift Capacity ◽  
Existing Structures ◽  
Cover Cracking ◽  
Experimental Findings

Corrosion is one of the major problems for the existing structures and may cause significant decrease in drift capacity and strength of RC (reinforced concrete) columns due to reduction of effective cross-section of reinforcing bars, alteration of bond characteristics between reinforcing bars and concrete, and cover cracking along the reinforcing bars. Therefore, rehabilitation of corrosion-damaged columns is extremely important, particularly in seismic regions and if a substandard construction methodology is used. In this paper, an experimental work is presented on the seismic performance of rehabilitated/retrofitted substandard RC columns, which were damaged due to corrosion of reinforcing bars. For this purpose, four substandard columns were tested under high axial load and reversed cyclic lateral loads. The columns were constructed with extremely low quality concrete and plain round bars. The spacing and details of transverse reinforcing bars did not comply with the code regulations as well. Then, the specimens, except the reference one, were subjected to accelerated corrosion process. One of the corrosion-damaged specimens was tested before rehabilitation/retrofitting procedure, while the other two specimens were tested after rehabilitation/retrofitting procedure. The test results clearly demonstrated the efficiency of the applied rehabilitation/retrofitting procedure, both in terms of strength and ductility. Furthermore, analytical predictions about strength and failure modes of the specimens are compared with experimental findings.

scholarly journals The analysis of influence of polymer admixtures on properties of lightweight concrete

2019 ◽  
Vol 252 ◽  
pp. 08007 ◽  
Author(s):  
Jacek Góra ◽  
Danuta Barnat-Hunek ◽  
Paweł Wlaź ◽  
Monika Garbacz
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Statistical Analysis ◽  
Lightweight Concrete ◽  
Strength Properties ◽  
Freezing And Thawing ◽  
Factors Of Influence ◽  
Freezing And Thawing Cycles ◽  
Acetate Copolymer

The article presents the results of testing physical and strength properties of concrete with the addition of lightweight perlite in the amount of 10 and 20%. The additive was introduced by volume substituting a part of the sand. In addition, the effect of using siloxane admixtures and a vinyl acetate copolymer with different degree of dosing, as well as applied simultaneously, were analysed. The tests were carried out in the field of bulk density and proper density, determination of tightness and porosity, compressive strength and tensile strength after 28 days of maturation. In terms of durability of concrete, absorption and resistance of concretes to the freeze-up effects after 100 freezing and thawing cycles were tested. The results of the study were subjected to statistical analysis using the analysis of variance. The analysed factors of influence were the amount of perlite addition, as well as the type and amount of the added admixture

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