Evaluation of Stress Block Parameters for Steel Fibre Reinforced SCC with Recycled Concrete Aggregate

2016 ◽  
Vol 857 ◽  
pp. 76-81
Author(s):  
Elizabeth John Neethu ◽  
S.R. Akhil Raj
Keyword(s):  
Equivalent Stress ◽  
Axial Loading ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Stress Strain ◽  
Design Strength ◽  
Steel Fibres ◽  
Granite Powder ◽  
Stress Block

Stress block parameters are predominantly used in the design of concrete structural members and offer a convenient method to arrive at the flexural capacity. The objective is to find the equivalent stress block parameters namely, the effective average concrete ratio and the stress block depth factor for Self Compacting Concrete with recycled aggregate (RSCC) and SCC with recycled aggregate incorporating steel fibres (SFRSCC) . SCC is defined as a highly workable concrete which flows by its own weight. Sustainability of SCC can be improved by replacing mineral aggregates by industrial waste like rubber, recycled aggregate, granite powder etc. An experimental investigation was carried out on the stress strain characteristics of SCC by partially replacing 25, 50, 75 and 100 % of coarse aggregate by recycled aggregate (RSCC) for varying design strength 30, 40, 50 MPa under monotonically increasing axial loading. The behavior of SCC with 100 % recycled aggregate incorporating steel fibres with different volumetric ratios is also explored. A total of 72 cylinders were prepared to develop a stress strain model for RSCC and SFRSCC. The results were compared with the existing models used for SCC and recycled aggregate and it indicates that Saenz model was found applicable for finding the stress block parameters. The proposed parameters were found to be lesser than the values for normal concrete specified by IS 456 and that these parameters could be used to determine the flexural strength of members made using the above composites.

Effect of Accelerated Curing on Strength of Quaternary Blended Cement Concrete with Recycled Aggregate

2021 ◽  
Vol 882 ◽  
pp. 247-253
Author(s):  
Vishal Akula ◽  
M.V.S.S. Sastri ◽  
P. Mahender ◽  
K. Jagannadha Rao
Keyword(s):  
Fly Ash ◽  
Blended Cement ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Cement Concrete ◽  
Design Strength ◽  
Accelerated Curing ◽  
Micro Silica

This paper presents the results of an experimental investigation carried out on accelerated curing of Quaternary Blended Cement (QBC) Concrete with and without recycled aggregate. Cement is partially replaced with fly ash, micro silica and nanosilica to produce QBC Concrete. The variables of study include the grade of concrete, powder content and percentage of recycled aggregate. Two grades of concrete M-40 and M-60 were used in this investigation. Based on the earlier studies, fly ash and micro silica are kept constant as 20% and 10% respectively while nanosilica is varied as 2% and 3%. Three percentages of recycled aggregate as partial replacement of natural aggregate (0%, 50% and 75%) were used. Two methods of curing were employed; boiling water method and hot air curing. The test results are encouraging and it is observed that 90% of the design strength could be achieved in one day for both the grades of concrete by curing at 100°C for a period of 3 hours. Keywords: Quaternary Blended Cement Concrete (QBCC), Fly ash (FA), Micro silica (SF), nanosilica (NSF), Recycled Concrete Aggregate (RCA), Accelerated Curing.

Recycling of Waste Concrete and Fly Ash for Recycled Aggregate Concrete: Fundamental Characteristics Evaluation

2009 ◽  
Vol 620-622 ◽  
pp. 255-258 ◽  
Author(s):  
Cheol Woo Park
Keyword(s):  
Fly Ash ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Recycled Concrete Aggregate ◽  
Aggregate Concrete ◽  
Waste Concrete

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.

Experimental Research on Mechanical Properties of Recycled Aggregate Concrete under Uniaxial Loading

2013 ◽  
Vol 671-674 ◽  
pp. 1736-1740
Author(s):  
Xue Yong Zhao ◽  
Mei Ling Duan
Keyword(s):  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

The complete stress-strain curves of recycled aggregate concrete with different recycled coarse aggregate replacement percentages were tested and investigated. An analysis was made of the influence of varying recycled coarse aggregate contents on the complete stress-strain curve, peak stress, peak strain and elastic modulus etc. The elastic modulus of RC is lower than natural concrete (NC), and with the recycled coarse aggregate contents increase, it reduces. While with the increase of water-cement ratio (W/C), recycled concrete compressive strength and elastic modulus improve significantly. In addition, put forward a new equation on the relationship between Ec and fcu of the RC.

scholarly journals Influence of Partial Coarse Fraction Substitution of Natural Aggregate by Recycled Concrete Aggregate in Hot Asphalt Mixtures

2019 ◽  
Vol 12 (1) ◽  
pp. 250 ◽  
Author(s):  
Debora Acosta Álvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio José Tenza-Abril ◽  
Salvador Ivorra
Keyword(s):  
Asphalt Concrete ◽  
Coarse Fraction ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Demolition Waste ◽  
Natural Aggregate

The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different recycled concrete aggregate (RCA) percentages (0%, 20%, 40%, 60% and 80% of the fraction 5–13 mm) and asphalt (4%, 4.5% and 5%). Dense asphalt mixtures were made; partially replacing the natural aggregate (NA) fraction between 5 and 13 mm. Marshall specimens were manufactured to determine the main properties of the asphalt concrete (AC) in terms of density, voids, stability and deformation. Additionally, the optimal asphalt content (OAC) was determined, and measured the water sensibility, the stiffness modulus and the permanent deformation. The results corroborate the potential for using these sources of construction and demolition waste (CDW) as a RCA in asphalt concrete and show that the hot asphalt mixtures with up to 40% substitution of natural aggregate by recycled aggregate in the fraction 5–13 mm present good behavior.

Research on Mixture Ratio of Recycled Concrete Aggregate in Concrete

2012 ◽  
Vol 193-194 ◽  
pp. 1371-1375
Author(s):  
Yong San Cheng ◽  
Ke Qiang Yu ◽  
Shuang Xi Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Raw Materials ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Mixture Ratio

In order to better understand the recycled concrete aggregate, it is essential to investigate the different mixture ratio in it. For determining the better mixture ratio of recycled concrete aggregate, the experimental investigation was conducted by making use of recycled concrete aggregate of different ratio instead of small stones in concrete, while maintaining the proportion of other raw materials of concrete unchanged. Its mechanical properties were also investigated. It is found that the better materials proportion of recycled concrete is that sand: recycled aggregate: water= 1: 1.8 : 2.1: 0.55.

Literature Review of Recycled Concrete Aggregate

2014 ◽  
Vol 638-640 ◽  
pp. 1162-1165
Author(s):  
Feng Xu
Keyword(s):  
Sustainable Development ◽  
Literature Review ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Cement Concrete ◽  
Concrete Construction ◽  
The Sustainable Development ◽  
And Performance

Make old cement concrete as recycled aggregate can not only protect environment, saving resources, but also can reduce the project cost, and promoting the sustainable development. This paper based on the related recycled concrete aggregate (RCA Recycled Concrete Aggregate) literature, mainly involve its properties, preparation and performance of RCA concrete, construction application etc..This has got a lot of reliable conclusions, so as to give some inspiration and help to the related scholars.

Utilization of Fine Recycled Aggregate and the Calcareous Fly Ash in CLSM Manufacturing

2014 ◽  
Vol 1054 ◽  
pp. 199-204 ◽  
Author(s):  
Wojciech Kubissa ◽  
Roman Jaskulski ◽  
Jacek Szpetulski ◽  
Anna Gabrjelska ◽  
Ewelina Tomaszewska
Keyword(s):  
Fly Ash ◽  
Fine Fraction ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Recycled Concrete Aggregate ◽  
River Sand ◽  
Wide Range ◽  
Strength Material

In the article the possibility of utilization of two waste materials: Recycled Concrete Aggregate (RCA) fraction 0-2 mm and Class C fly ash (from lignite burning power plant) in Controlled Low-Strength Material (CLSM) was presented. The research covered twelve different mixtures. The mixtures differed in cement and fly ash content as well as content of the fine aggregate. As a fine aggregate 0-2 mm fraction of RCA or river sand were used. The results showed that use the fine fraction RCA instead of sand does not cause technological problems and allows, depending on the needs, obtaining the material with different properties and a wide range of applications.

Analysis of Microstructure of Interfacial Transition Zone (ITZ) in Recycled Aggregate Concrete

2013 ◽  
Vol 811 ◽  
pp. 249-253 ◽  
Author(s):  
Wei Li ◽  
Hai Ying Zhang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Interfacial Structure ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Interfacial Zone ◽  
Aggregate Concrete ◽  
Mortar Strength

Experiments on influence of species of aggregate and mixing method on interfacial zone in recycled aggregate concrete were investigated. SEM observations revealed that a recycle normal-strength concrete aggregate consist of loose and porous interfacial structure, whereas a recycled high performance concrete (HPC) aggregate and a triple mixing (TM) consist mainly of dense hydrates. Various admixtures on ITZ was produced that consumed CH in the pore, modified attached cement mortar. Strength of recycled concrete was explained by interaction between cements paste and recycled aggregate. The result verified that the relatively dense pore structure of the recycled concrete benefit to development of mechanical properties.

Evaluation of Recycled Aggregate Concrete Cracking through Ring Test

2012 ◽  
Vol 174-177 ◽  
pp. 1475-1480 ◽  
Author(s):  
Valeria Corinaldesi ◽  
Giacomo Moriconi
Keyword(s):  
Numerical Models ◽  
Creep Behaviour ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Tensile Creep ◽  
Ring Test ◽  
Early Age ◽  
Concrete Aggregate ◽  
Free Shrinkage

Cracks can reduce the service life of a concrete structure by allowing aggressive agents to penetrate through it in easy ways. Free shrinkage evaluation alone is not enough to determine if cracking can be expected in a structure since concrete creep behaviour, stiffness and toughness also influence the potential for cracking. Consequently, it is rather interesting to perform restrained shrinkage tests, such as the ring test according to ASTM C 1581–04. The testing procedure involves concrete ring specimens restrained by an inner steel ring on which strain gauges are placed to determine the age of cracking, since abrupt changes in the steel strain occur when concrete is cracked. Both the ring test and free shrinkage test should be carried out in the same exposure conditions, 21°C and 50% relative humidity. Moreover, compressive and tensile strengths of concrete were evaluated on cubic specimens at the time of its cracking and up to 28 days of curing. By means of analytical and numerical models of the ring specimen, some useful information on the stress induced in the material and on the tensile creep behaviour of concrete can be extrapolated thus allowing to better interpret the experimental results. This experimental procedure enables to study the influence of concrete mixture composition on the potential for early-age cracking of concrete. In particular, in this work the influence on early-age cracking of recycled-concrete aggregate partially replacing virgin sand was tested.

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