A Comparative Investigation on Normal and High Strength Concrete Beams under Torsion

2022 ◽  
Vol 1048 ◽  
pp. 359-365
Author(s):  
Ihtesham Hussain Mohammed ◽  
Ahmed Majid Salim Al Aamri ◽  
Shakila Javed ◽  
Yahya Ubaid Al Shamsi
Keyword(s):  
High Strength Concrete ◽  
Concrete Beams ◽  
High Strength ◽  
Comparative Investigation ◽  
Mineral Admixtures ◽  
Torsional Loading ◽  
Torsional Strength ◽  
Strength Concrete ◽  
Loading Method ◽  
Normal Strength

In this study, an experimental investigation was done to study the behaviour of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) Plain beams under torsion with the concrete mix of M40 and M100. No mineral admixtures are used to obtain the required strength of concrete. Eight NSC beams and eight HSC beams whose width was varying with 75 mm, 100 mm, and 150 mm; depth varying as 75 mm, 100 mm, 150 mm and 200 mm; and span of the beams varying 600 mm, 800 mm and 1200 mm were casted and cured to stud the effect of torsion. The principle aim of this study was to understand the torsional behaviour of the NSC and HSC beams for rotation, cracking, size effect and torsional strength. A standard torsional loading method was used for conducting the testing of beams. The results obtained were compared with different theories and code equations. It was observed that the torsional strength of the beam increases with the increase in strength of concrete. HSC beams have higher torsional strength than the NSC beams which has the same amount of reinforcement.

Superplasticizer for High Strength Concrete

2015 ◽  
Vol 1768 ◽  
Author(s):  
Luis E. Rendon Diaz Miron ◽  
Maria E. Lara Magaña
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
High Strength Concrete ◽  
High Strength ◽  
Mineral Admixtures ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength ◽  
Ready Mixed Concrete ◽  
Mixed Concrete

ABSTRACTIn the early 1970s, experts predicted that the practical limit of ready-mixed concrete would be unlikely to exceed a compressive strength greater than 90 MPa [1]. Over the past two decades, the development of high-strength concrete has enabled builders to easily meet and surpass this estimate. The primary difference between high-strength concrete and normal-strength concrete relates to the compressive strength that refers to the maximum resistance of a concrete sample to applied pressure. Although there is no precise point of separation between high-strength concrete and normal-strength concrete, the American Concrete Institute defines high-strength concrete as concrete with a compressive strength greater than 45 MPa. Manufacture of high-strength concrete involves making optimal use of the basic ingredients that constitute normal-strength concrete. When selecting aggregates to obtain high-strength concrete, we consider strength, optimum size distribution, surface characteristics and a good bonding with the cement paste that affect compressive strength. Selecting a high-quality Portland cement and optimizing the combination of materials by varying the proportions of cement, water, aggregates, and admixtures is also necessary. Any of these properties could limit the ultimate strength of high-strength concrete. Pozzolans, such as fly ash and silica fume along with silicic acid, are the most commonly used mineral admixtures in high-strength concrete. These materials impart additional strength to the concrete by reacting with Portland cement hydration products to create additional Calcium Silicate Hydrate (CSH) gel, the part of the paste responsible for concrete strength; finally the most important admixture is polycarboxylate ether as super plasticizer. It would be difficult to produce high-strength ready-mixed concrete without using chemical admixtures. In this paper we study the use of high performance concrete (HPC) to obtain very narrow strong pre-fabricated elements for water conducting channels.

Flexural and Shear Capacity Evaluation of Reinforced Ultra-High Strength Concrete Members with Steel Rebars

2013 ◽  
Vol 577-578 ◽  
pp. 17-20 ◽  
Author(s):  
Baek Il Bae ◽  
Hyun Ki Choi ◽  
Chang Sik Choi
Keyword(s):  
High Strength Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Steel Fiber Reinforced Concrete ◽  
Strength Concrete ◽  
Ultra High Strength Steel ◽  
Normal Strength

High-strength concrete is widely used in construction field. The growth has been possible as a result of recent developments in material technology and a demand for high-strength concrete. High-strength concrete has different mechanical properties from normal-strength, as many researches mentioned about. However, the existing equations and procedures for prediction of ultra-high strength concrete are based on tests using normal-strength concrete, yet. In this study, experiments on ultra-high-strength steel fiber reinforced concrete beams with 2% volume fraction of steel fiber and 200MPa of compressive strength have been conducted. Test was conducted by two point loading with 2,000kN actuator for slender test specimen which have varied shear-span to depth ratio. Using test results with several assumptions, an empirical equation for flexural strength and shear strength of ultra-high-strength steel fiber reinforced concrete beams have been proposed.

Experimental investigation of the flexural ductility of singly reinforced concrete beam using normal and high strength concrete

2019 ◽  
Vol 1 (2) ◽  
pp. 218-224
Author(s):  
Atur P.N. Siregar
Keyword(s):  
Experimental Investigation ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Flexural Ductility ◽  
Normal Strength

This paper discusses and reports based on the experimental investigation of the flexural ductility of singly reinforced normal strength and high strength concrete beams. Compressive concrete strength of 40 and 95 MPa were employed to create singly reinforced normal strength and high strength concrete beams, respectively. Fourteen samples made of normal and high strength concrete were engaged to observe the flexural ductility behaviour of beams on the basis of four point bend testing. Analysis on the basis of the flexural cracking, ultimate failure and curvature ductility were carried out to derive the comparison of singly reinforced normal strength and high strength beams. The beams using high strength concrete revealed a higher ductility ratio than that of normal strength concrete, i.e. 4.50 for high strength concrete and 2.60 for normal strength concrete.

Prestressed high-strength concrete beams under torsion and bending

1999 ◽  
Vol 26 (2) ◽  
pp. 197-207
Author(s):  
Samir A Ashour ◽  
Sabry A Shihata ◽  
Ali A Akhtaruzaman ◽  
Faisal F Wafa
Keyword(s):  
Prestressed Concrete ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
High Strength ◽  
Torsional Stiffness ◽  
Test Results ◽  
Torsional Strength ◽  
Interaction Diagram ◽  
Strength Concrete

Test results of 16 rectangular prestressed high-strength concrete beams subjected to the combined action of torsion and bending are presented. The major variables were the ratio of torsion to the bending moment (T/M) and the prestressing level. The beams were subjected to two levels of prestressing, corresponding to 0.05fc' and 0.10fc', where fc' is the compressive strength of concrete (about 90 MPa). Test results showed that the torque-twist relations for the test beams were approximately linear up to cracking and thereafter became nonlinear. Increasing the T/M ratio and the prestressing level increases both torsional stiffness and strength. Several theoretical methods available in the literature developed for normal-strength concrete were used to predict the torsional strength of the tested high-strength concrete beams. Interaction equations were used along with some other methods to predict the torsional capacity in the presence of a bending moment. Good agreement was observed between the experimental and theoretical results.Key words: beams (supports), bending, cracking, failure, high-strength concrete, interaction diagram, prestressed concrete, stiffness, torsion, torsional strength.

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