Effect Of Specimen Size and Shape on Compressive Strength of Self-Compacting Concrete

2014 ◽  
Vol 7 (2) ◽  
pp. 16-29
Author(s):  
Mohammed Karem Abd ◽  
Zuhair Dhaher Habeeb
Keyword(s):  
Compressive Strength ◽  
Correction Factor ◽  
High Strength Concrete ◽  
High Strength ◽  
Specimen Size ◽  
Self Compacting Concrete ◽  
Normal Concrete ◽  
Cube Strength ◽  
Strength Concrete ◽  
Size And Shape

This study aims to show the effect of specimen size and shape on compressive strength of self-compacting concrete (SCC). The work is divided into two parts, the first was to designed Normal Concrete (NC), High Strength Concrete (HSC) and Self Compacting Concrete (SCC) of strength between (25-70) MPa. from locally available materials. The values percent of cylinder to cube strength were between (0.86-0.9), (0.94-0.96), (0.96-0.99) of NC, HSC and SCC respectively.The second is to investigate the effect of specimen size on compressive strength, the values of correction factor of cube specimens (150*150*150)mm and (100*100*100)mm is (0.89-1.29), (0.98-1.26) and (0.98-1.22) of NC,HSC and SCC respectively. The values of correction factor of cylinder specimens of (150*300) mm and (100*200) mm is (0.88-1.08), (0.93-1.07) and (0.95-1.04) of NC, HSC and SCC respectively.

scholarly journals Effect of Steel Fiber Aspect Ratio on the Properties of High Strength Self Compacting Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 2938-2941
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Fibers ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Strength Concrete ◽  
Fiber Aspect Ratio ◽  
Aspect Ratios ◽  
Hardened Properties

The High strength concrete defined as per IS 456 as the concrete having characteristic compressive strength more than 65 MPa. The self-compacting concrete has lot of advantages including concreting at congested reinforcement locations, better finish, good compaction etc. The inclusion of fibers in the concrete mix decreases the brittle nature of concrete thereby the ductility increases. Different types of fibers are available for inclusion in concrete like steel, glass, polypropylene, basalt, etc. In the present investigation, high strength concrete having characteristic strength of 90 MPa was developed and hooked ended steel fibers are used and the hardened properties are determined. Steel fibers having diameter of 1 mm and lengths of 25 and 50 mm were added to concrete in 0.125%, 0.25% and 0.5% by volume of concrete. Three hardened properties compressive strength, split tensile Strength and flexural strength were determined. Out of the two lengths of fiber i.e with two aspect ratios, the fiber with 50 mm length yielded better results.

scholarly journals The Use of Fly Ash as Additive Material to High Strength Concrete

2018 ◽  
Vol 20 (2) ◽  
pp. 65-70
Author(s):  
Endah Kanti Pangestuti ◽  
Sri Handayani ◽  
Mego Purnomo ◽  
Desi Christine Silitonga ◽  
M. Hilmy Fathoni
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Building Materials ◽  
High Strength ◽  
Coal Waste ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

Abstract. The use of coal waste (Fly Ash) is currently being developed in building materials technology, as a high-strength concrete mix material. This study aims to determine the strength of concrete by adding fly ash as a substitute for cement in high-strength concrete mixtures. This research was conducted with an experimental method to obtain results and data that would confirm the variables studied. The total number of specimens used in this study were 36 pieces with different sizes of cube tests which were 15 cm x 15 cm x 15 cm. A total of 36 concrete samples were used to test the compressive strength of concrete with a percentage of Fly Ash in  0% (normal concrete), 20%, 25% and 30% with a concrete treatment age of 7 days, 21 days and 28 days. A total of 12 more samples were used to test water absorption in concrete at 28 days of maintenance. Each percentage percentage of Fly Ash uses 3 concrete test samples. The increase in compressive strength occurs at 7, 21 and 28 days in concrete. However, the compressive strength of concrete produced by concrete using the percentage of Fly Ash is always lower than the value of normal concrete compressive strength. From testing the compressive strength of concrete at 28 days of treatment with content of 0%, 20%, 25% and 30% Fly Ash obtained results of 45.87 MPa, 42.67 MPa, 40.89 MPa, and 35.27 MPa respectively

scholarly journals Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 822 ◽  
Author(s):  
Farhad Aslani ◽  
Fatemeh Hamidi ◽  
Qilong Ma
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Self Compacting Concrete ◽  
Strength Concrete ◽  
Magnetite Content ◽  
Hardened State

In this study, the fresh and hardened state properties of heavyweight self-compacting concrete (HWSCC) and heavyweight high strength concrete (HWHSC) containing heavyweight magnetite aggregate with 50, 75, and 100% replacement ratio, and their performance at elevated temperatures were explored experimentally. For fresh-state properties, the flowability and passing ability of HWSCCs were assessed by using slump flow, T500 mm, and J-ring tests. Hardened-state properties including hardened density, compressive strength, and modulus of elasticity were evaluated after 28 days of mixing. High-temperature tests were also performed to study the mass loss, spalling of HWSCC and HWHSC, and residual mechanical properties at 100, 300, 600 and 900 °C with a heating rate of 5 °C/min. Ultimately, by using the experimental data, rational numerical models were established to predict the compressive strength and modulus of elasticity of HWSCC at elevated temperatures. The results of the flowability and passing ability revealed that the addition of magnetite aggregate would not deteriorate the workability of HWSCCs and they retained their self-compacting characteristics. Based on the hardened densities, only self-compacting concrete (SCC) with 100% magnetite content, and high strength concrete (HSC) with 75 and 100% magnetite aggregate can be considered as HWC. For both the compressive strength and elastic modulus, decreasing trends were observed by introducing magnetite aggregate to SCC and HSC at an ambient temperature. Mass loss and spalling evaluations showed severe crack propagation for SCC without magnetite aggregate while SCCs containing magnetite aggregate preserved up to 900 °C. Nevertheless, the mass loss of SCCs containing 75 and 100% magnetite content were higher than that of SCC without magnetite. Due to the pressure build-up, HSCs with and without magnetite showed explosive spalling at high temperatures. The residual mechanical properties analysis indicated that the highest retention of the compressive strength and modulus of elasticity after exposure to elevated temperatures belonged to HWSCC with 100% magnetite content.

scholarly journals Effect of size and shape of specimen on compressive strength of glass fiber reinforced concrete (GFRC)

2011 ◽  
Vol 9 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Rao Krishna ◽  
Rathish Kumar ◽  
B. Srinivas
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Glass Fiber ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Strength Concrete ◽  
Size And Shape ◽  
Glass Fiber Reinforced ◽  
Compressive Strength Of Concrete

Concrete is a versatile material with tremendous applications in civil engineering construction. Structural concrete elements are generally made with concrete having a compressive strength of 20 to 35 MPa. Lately, there is an increase in use of high strength concrete (HSC) in major construction projects such as high-rise buildings, and bridges involving members of different sizes and shapes. The compressive strength of concrete is used as the most basic and important material property in the design of reinforced concrete structures. It has become a problem to use this value as the control specimen sizes and shapes are different from country to country. In India, the characteristic compressive strength is usually measured based on 150 mm cubes [1]. But, the ACI code of practice specifies the design compressive strength based on the standard 150x300 mm cylinders [2]. The use of 100x200 mm cylinders gained more acceptance as the need to test high strength concrete increases [3]. In this context the size and shape of concrete becomes an important parameter for the compressive strength. In view of the significance of compressive strength of concrete and due to the fact that the structural elements of different sizes and shapes are used, it is proposed to investigate the effect of size and shape of the specimen on the compressive strength of concrete. In this work, specimens of plain as well as Glass Fiber Reinforced Concrete (GFRC) specimens are cast in order to carry out a comparative study.

Tensile behavior of stud connectors in high strength concrete

2021 ◽  
pp. 136943322110297
Author(s):  
Fuhai Li ◽  
Hao Gao ◽  
Yilin Jiang ◽  
Tao Wen ◽  
Yulin Zhan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Failure Mode ◽  
High Strength Concrete ◽  
Composite Structures ◽  
Prediction Models ◽  
High Strength ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Pull Out ◽  
Lower Ratio

Stud connectors are commonly used in steel-concrete composite structures. As high strength concrete (HSC) will be applied in the construction of a composite structure, it is needed to study the performance of stud connectors in HSC. In this study, tension (pull-out) tests were conducted on the studs with different combinations of diameters- d(13, 16, and 19 mm) and effective embedment depths- h ef (40, 60, and 80 mm) in HSC with a 28-day compressive strength of 88 MPa. Based on the experimental results, the concrete breakout failure mode dominates and only the scenario with the smallest diameter and largest h ef is controlled by steel failure mode. Because of high strength, the steel failure occurs at smaller h ef/ d in HSC than normal concrete. In the concrete breakout failure mode, brittle load–displacement behaviors are presented and the angle of the breakout cone ranges from 30∼35°, which is close to the concrete capacity design (CCD) method. Also, the ultimate tensile strength ( N u), stiffness, and pre-peak ductility are dependent on h ef and diameter . The existing prediction models (CCD method and variable angle cone method) both overestimate the N u in HSC, which is due to its lower ratio tensile/compressive strength than normal concrete. Considering the mechanism of how the breakout cone is formed, a modified reduced_CCD method is proposed for predicting N u of studs in HSC.

scholarly journals Effect of Maximum Aggregate Size on the Strength of Normal and High Strength Concrete

2020 ◽  
Vol 6 (6) ◽  
pp. 1155-1165
Author(s):  
Gaith Abdulhamza Mohammed ◽  
Samer Abdul Amir Al-Mashhadi
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
Design Method ◽  
High Strength ◽  
Maximum Size ◽  
Normal Strength Concrete ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Normal Strength

Aggregates form 60% to 75% of concrete volume and thus influence its mechanical properties. The strength of (normal or high-strength) concrete is affected by the maximum size of a well-graded coarse aggregate. Concrete mixes containing larger coarse aggregate particles need less mixing water than those containing smaller coarse aggregates, In other words, small aggregate particles have more surface area than a large aggregate particle. In this research, about twenty-two mixtures were covered to study the effect of the MSCA, on compressive strength of (normal strength concrete) and Sixteen mixtures to study the effect of the maximum size of coarse aggregate on compressive strength for (high strength concrete). The concrete mixture is completely redesigned according to the maximum size of coarse aggregate needs and maintaining uniform workability for all sizes of coarse aggregate. The American design method was adopted ACI 211.1, for normal concrete. ACI 211-4R, the design method was adopted for high strength concrete. And use the MSCA with dimensions (9.5, 12.5, 19, 25, 37.5, and 50) mm for normal strength concrete and the MSCA (9.5, 12.5, 19, and 25) mm for high strength concrete. The slump was fixed (75-100) mm for normal strength concrete. Slump is fixed to (25-50) mm for high strength concrete before added Superplasticizer high range water reducer (HRWR). With Fineness Modulus (F.M) fixed to 2.8 for both normal concrete and high-strength concrete. According to the results of the tests, the compressive strength increases with the increase in the MSCA, of the normal concrete and also high – strength concrete. And the effect of the MSCA, on the compressive strength of normal concrete, is higher than that of high-strength concrete.

Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Strength Concrete ◽  
Calcium Nitrite ◽  
Orientation Index ◽  
Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

Effect of Chopped Basalt Fiber on the Fresh and Hardened Properties of Fly Ash High Strength Concrete

2014 ◽  
Vol 567 ◽  
pp. 381-386 ◽  
Author(s):  
Nasir Shafiq ◽  
Muhd Fadhil Nuruddin ◽  
Ali Elheber Ahmed Elshekh ◽  
Ahmed Fathi Mohamed Salih
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Basalt Fiber ◽  
High Strength ◽  
Progressive Increase ◽  
Test Results ◽  
Strength Concrete ◽  
Hardened Properties ◽  
Chopped Basalt Fiber

In order to improve the mechanical properties of high strength concrete, HSC, several studies have been conducted using fly ash, FA. Researchers have made it possible to achieve 100-150MPa high strength concrete. Despite the popularity of this FAHSC, there is a major shortcoming in that it becomes more brittle, resulting in less than 0.1% tensile strain. The main objective of this work was to evaluate the fresh and hardened properties of FAHSC utilizing chopped basalt fiber stands, CBFS, as an internal strengthening addition material. This was achieved through a series of experimental works using a 20% replacement of cement by FA together with various contents of CBFS. Test results of concrete mixes in the fresh state showed no segregation, homogeneousness during the mixing period and workability ranging from 60 to 110 mm. Early and long terms of compressive strength did not show any improvement by using CBFS; in fact, it decreased. This was partially substituted by the effect of FA. Whereas, the split and flexural strengths of FASHC were significantly improved with increasing the content of CBFS as well as the percentage of the split and flexural tensile strength to the compressive strength. Also, test results showed a progressive increase in the areas under the stress-strain curves of the FAHSC strains after the CBFS addition. Therefore, the brittleness and toughness of the FAHSC were enhanced and the pattern of failure moved from brittle failure to ductile collapse using CBFS. It can be considered that the CBFS is a suitable strengthening material to produce ductile FAHSC.

Influence of Nano Particles in the Flexural Behavior of High-Strength Reinforced Concrete Beams

2021 ◽  
Vol 1160 ◽  
pp. 25-43
Author(s):  
Naglaa Glal-Eldin Fahmy ◽  
Rasha El-Mashery ◽  
Rabiee Ali Sadeek ◽  
L.M. Abd El-Hafaz
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Nano Particles ◽  
Flexural Behavior ◽  
Single Type ◽  
Strength Concrete ◽  
Flexural Ductility

High strength concrete (HSC) characterized by high compressive strength but lower ductility compared to normal strength concrete. This low ductility limits the benefit of using HSC in building safe structures. Nanomaterials have gained increased attention because of their improvement of mechanical properties of concrete. In this paper we present an experimental study of the flexural behavior of reinforced beams composed of high-strength concrete and nanomaterials. Eight simply supported rectangular beams were fabricated with identical geometries and reinforcements, and then tested under two third-point loads. The study investigated the concrete compressive strength (50 and 75 N/mm2) as a function of the type of nanomaterial (nanosilica, nanotitanium and nanosilica/nanotitanium hybrid) and the nanomaterial concentration (0%, 0.5% and 1.0%). The experimental results showed that nano particles can be very effective in improving compressive and tensile strength of HSC, nanotitanium is more effective than nanosilica in compressive strength. Also, binary usage of hybrid mixture (nanosilica + nanotitanium) had a remarkable improvement appearing in compressive and tensile strength than using the same percentage of single type of nanomaterials used separately. The reduction in flexural ductility due to the use of higher strength concrete can be compensated by adding nanomaterials. The percentage of concentration, concrete grade and the type of nanomaterials, could predominantly affect the flexural behavior of HSRC beams.

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