scholarly journals Experimental investigation on use of ferrochrome slag as an alternative to natural aggregates in concrete structures

2021 ◽  
Author(s):  
P N Ojha ◽  
◽  
Abhishek Singh ◽  
Brijesh Singh ◽  
Vikas Patel ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Concrete Structures ◽  
Ferrochrome Slag ◽  
Natural Aggregates

Behavior of Continuous FRP Rectangular Spirals as Shear Reinforcement for Concrete Beams

2011 ◽  
Vol 418-420 ◽  
pp. 307-312
Author(s):  
Shi Yong Jiang ◽  
Bing Hong Li ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Experimental Investigation ◽  
Tensile Strength ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Test Method ◽  
Test Results ◽  
Shear Reinforcement ◽  
Straight Portion ◽  
Embedment Length

The replacement of steel stirrups with FRP stirrups in concrete structures can significantly improve the durability under severe environmental conditions, increase the service life of the structure. In some cases where the application of traditional concrete structures is restricted, such as structures that require the environment without magnetic and electric interferences, the best way is to use nonmetallic materials. Considering the unique properties compared with traditional reinforcements, FRP reinforcements is very suitable in such cases. This paper discussed the behavior of FRP stirrups used as shear reinforcement for concrete structures, continuous FRP rectangular spirals, a type of FRP stirrups, was used in the experimental investigation. Inspired by the test method suggested by ACI Committee 440, L shape specimen and U shape specimen are designed to test the tensile strength of continuous FRP rectangular spirals. Through the analysis of test results, it is indicated that the strength of the bent portion of FRP spirals is significantly lower than that of the straight portion, and the strength of FRP spirals would increase as the concrete strength or the embedment length of the bent portion increased. The loading mechanism of continuous FRP rectangular spirals embedded in concrete beams can be better represented by U shape specimen compared with L shape specimens, it is suggested by the author that the U shape specimen can be use when the dimension of FRP stirrups or spirals does not meet the requirements of ACI Committee 440 test method.

Numerical Analysis of Effect of Cyclic Thermal Load on Concrete to Concrete Bonding

2016 ◽  
Vol 722 ◽  
pp. 18-26 ◽  
Author(s):  
Yuliia Khmurovska ◽  
Petr Štemberk ◽  
Martin Petřík ◽  
Ippei Maruyama ◽  
Ondřej Holčapek
Keyword(s):  
Experimental Investigation ◽  
Thermal Load ◽  
Thermal Loading ◽  
Concrete Structures ◽  
High Quality ◽  
Bonding Quality ◽  
Critical Stresses ◽  
First Results ◽  
Adhesive Materials

This paper presents a numerical simulation and preliminary experimental investigation of bonding of concrete structures using cement and polymer cement as adhesive materials. The numerical model of concrete plates bonded with the polymer cement is created and subjected to cyclic thermal loading. As a result, the critical stresses are obtained. Also all the necessary materials for carrying out high-quality, fast and inexpensive experimental investigation of the strength of cement and polymer cement bond are prepared. The experimental setup and the first results obtained are also described. The bonding quality of the polymer cement shows satisfactory results under this kind of loading, thus the use of the polymer cement for bonding of concrete structures of different properties is reasonable in the specific fields considered in this study.

scholarly journals Behaviour of Glass in Cement-Based Materials: Its Role on ASR

2012 ◽  
Vol 730-732 ◽  
pp. 415-420 ◽  
Author(s):  
D. Serpa ◽  
António Santos Silva ◽  
D. Soares ◽  
M. Barreto Santos ◽  
J. de Brito
Keyword(s):  
Concrete Structures ◽  
Fine Powder ◽  
Mineralogical Composition ◽  
Hardened Concrete ◽  
Replacement Ratio ◽  
Cement Based Materials ◽  
Mineral Additions ◽  
Naoh Solution ◽  
Natural Aggregates ◽  
Preventive Methods

One of the most worrying degradation mechanisms in hardened concrete is the occurrence of chemical expansive reactions, namely due to alkali-silica reactions (ASR). This pathology involves the formation of expansive products inside the material. This situation is very difficult to deal with, because presently there is no efficient method to repair concrete structures affected by ASR. Hence, there is an urgent need to find preventive methods that may inhibit these reactions in new concrete structures. Nowadays, the use of pozzolanic mineral additions is recommended to mitigate this type of degradation. Moreover, their effect depends on their chemical and mineralogical composition and also on the cement content replacement ratio. Glass is a common material with some environmental problems regarding recycling and landfilling. Some studies exist about its use as fine powder, like a pozzolan, in cement-based materials. However, there are also some problems related to its use as coarse aggregate in cement–based materials due to ASR development. This paper presents the results obtained in mortars exposed to 1M NaOH solution prepared with crushed glass as aggregate and as addition in cement substitution. The results reveal that ASR is reduced with the incorporation of glass as aggregate or addition, and its efficiency depends on its replacement content. This study shows that an incorporation of glass aggregates up to 20% in mass will generate no significant expansion when compared with concrete made with natural aggregates.

scholarly journals Effect of Fibers on the Bond Behavior of Deformed Steel Bar Embedded in Recycled Aggregate Concrete

2020 ◽  
Vol 39 (4) ◽  
pp. 846-858
Author(s):  
Rashid Hameed ◽  
Usman Akmal ◽  
Qasim S. Khan ◽  
Muhammad Ahsan Cheema ◽  
Muhammad Rizwan Riaz
Keyword(s):  
Compressive Strength ◽  
Concrete Structures ◽  
Steel Fibers ◽  
Recycled Aggregates ◽  
Polypropylene Fibers ◽  
Reinforcing Bars ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bar ◽  
Natural Aggregates

A large volume of concrete debris is being produced in many countries on the globe due to the demolition of old concrete structures and testing of concrete specimens in laboratories. One of the ways to reuse concrete debris is to produce Recycled Aggregates (RA) and use them in new concrete. In recent years, Recycled Aggregates Concrete (RAC) has experienced increasing demand in various non-structural and structural applications. In reinforced concrete structures, one of the sources of brittle failure is sudden loss of bond between reinforcing bars and concrete in anchorage zones. Therefore, for the structural application of any new kind of concrete such as fiber reinforced RAC, knowledge of bond characteristics of reinforcing bars embedded in concrete becomes essential for determining the overall structural response under different modes of loading. In this regard, this study experimentally investigated the effect of fibers on the bond stress-slip behavior of deformed steel re-bar embedded in RAC. Concrete mixes having 0, 50 and 100% RAs were prepared with and without the addition of fibers. Two types of fibers were investigated in mono form: hooked-ends steel and polypropylene fibers. The dosage of steel and polypropylene fibers was kept 40 and 4.4 kg/m3, respectively. Axial compression and standard pull-out tests were performed. Test specimens for pull-out test were prepared using deformed steel re-bars of 19mm (#6) diameter. The results of strength tests confirmed that the compressive strength of concrete is decreased by replacing Natural Aggregates (NA) with RAs. For bond behavior of steel re-bar, the results of this study showed that replacement of 50% NA with RAs did not affect the bond response of steel bar, however, 100% replacement of NA with RAs showed detrimental effect on bond stress slip behavior. The results further showed that the addition of both types of fibers made it possible to recover the loss in compressive strength, bond strengths and bond toughness occurred because of replacing NA with RAs. In case of RA concrete mixes containing hooked-ends steel fibers, strength values were found even greater than the strength values of Natural Aggregates Concrete (NAC). From the results of this study, it was found that it is possible to design a structural concrete mix using 100% RAs and steel fibers at relatively low dosage of 40kg/m3.

Experimental investigation of the progressive collapse of reinforced concrete structures: An overview

Structures ◽  
2020 ◽  
Vol 25 ◽  
pp. 881-900 ◽  
Author(s):  
Ibrahim M.H. Alshaikh ◽  
B.H. Abu Bakar ◽  
Emad A.H. Alwesabi ◽  
Hazizan Md Akil
Keyword(s):  
Experimental Investigation ◽  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Concrete Structures ◽  
Reinforced Concrete Structures
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