Crushed Returned Concrete as Aggregates for New Concrete

One study found that in order to produce similar workability as VA concrete 5% more mixing water was required when using just the coarse fraction of recycled concrete aggregates (coarse RCA) and up to 15% more mixing water when using both the coarse and fine fractions of RCA8-11. Issues of

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Workability study of concretes made with recycled mortar ...

The use of recycled aggregates (RA) for concrete production usually involves a reduction of the workability as measured by slump. This reduction is mainly due to higher absorption rates, rough-textured surfaces and particles with quite irregular shape from RA. Besides that, the slump test is a static test, whose result is influenced by its own weight and by internal friction between …

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Recycling of Concrete (Recycling Coarse Aggregate) – IJERT

Recycling of concrete is a simple process. It involves breaking, removing, and crushing existing concrete into a material with a specified size and quality. As per study about 75 to 80% of total construction material consist coarse aggregate portion. When the structure is demolished, the waste concrete in a large quantity is produced.

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Experimental Study on the Workability of Recycled Fine ...

Recycled concrete, or recycled aggregate concrete, is the concrete generated by mixing a certain proportion of cement and sand with waste concrete after being mechanically crushed, cleaned and screened. The workability of the concrete is determined by the rheological property of the mixture; the fluidity and workability of the fresh cement

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Workability and Compressive Strength of Recycled Concrete ...

The recycled concrete waste aggregate (RCWA) was tested for grading, specific gravity, percent absorption and impact and crushing (% crushed). For the fresh concrete mix, slump and compaction factor test were carried out. Concrete samples are wet cured and tested at 7 and 28 days for compressive strength. Results show that the workability of ...

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Assessment of Recycled Aggregate Concrete

workability of the concrete using recycled aggregate. 2. Evaluation of Recycled Aggregate Properties Recycled aggregate can be generated from demolished construction structure which comprises of broken members or components likes the slab, beam, brick wall and others. Since the quality data of these broken materials are often

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Workability, strength, and microstructure of high strength ...

This study examines the workability, strength, and microstructure of high strength eco-concrete incorporating recycled clay brick aggregate and calcined clay. The study adopted a design mixes proportioning of 1:1:2 by weight at a constant water/binder ratio of 0.25.

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Development of Concrete Incorporating Recycled Aggregates ...

Recycling of construction and demolition waste is a central point of discussion throughout the world. The application of recycled concrete as partial replacement of mineral aggregates in concrete mixes is one of the alternatives in the reduction of pollution and savings in carbon emissions. The combined influence of the recycled crushed concrete, lime, and natural pozzolana on the mechanical ...

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Properties of high-workability concrete with recycled ...

Keywords: hardened properties, natural coarse aggregate, recycled concrete aggregate, workability. 1. Introduction. Construction developments are on its peak in the 21 st century around the globe. There are numerous sky-scrapers, bridges, roads, underground tunnels, …

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Recycling used engine oil in concrete design mix: An ...

The improvement in the workability of concrete mixtures can be ascribed to steric hindrance and ball-bearing effects from well dispersed O/W emulsion. The enhancement in the compressive strength can be attributed to the filler effect of the well-dispersed microscale particles of UEO. ... Utilizing recycled aggregate concrete in sustainable ...

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The effect of superplasticisers on the workability and ...

The recycled concrete aggregates have a significant water absorption capacity in a concrete mix. The simple volume replacement of NA by RA affects concrete workability and performance. For the mixing period of 10 minutes suggested by Evangelista and de Brito it was ...

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EFFECT OF RECYCLED COARSE AGGREGATE ON …

Concrete (FRHSC) which use recycled aggregates that have originated from demolished construction wastes.The workability of FRHSC was measured in terms of compaction factor and V-B time in fresh state of concrete.

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Aggregates for Concrete

mately 60 to 75% of the volume of concrete. Aggregate properties significantly affect the workability of plastic concrete and also the durability, strength, thermal properties, and density of hardened concrete. This Bulletin describes types of aggregates normally used in …

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Mechanical and Durability Properties of Recycled Aggregate ...

The use of recycled concrete aggregates as an alternative aggregate material in concrete has been studied over the past two decades. It is now recognized that the recycled aggregate concrete (RAC), where natural aggregates are replaced with recycled concrete aggregates, is a promising technology for conserving natural resources and reducing the environmental impact of concrete.

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Workability and Early-Age Strength of Recycled Aggregate ...

tensile strengths of concrete made with recycled concrete aggregates (RCA). The target concrete compressive strengths were 30, 45, and 60 MPa, whereas the basalt fibers had a length of either 20 or 43 mm. The addition of BF significantly decreased the workability, slightly improved the compressive strength, and

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PennDOT RECYCLING MATERIAL BRIEF Recycled Concrete ...

aggregate has no significant effect on mixture proportions or workability when compared with control mixtures made with conventional aggregates. Although there are limitations to using recycled fine aggregates, these drawbacks can be generally overcome by …

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Experimental Study of Compressive Strength of Recycled ...

The basic engineering properties of Recycled Concrete Aggregate (RCA) is evaluated and it is compared with the Normal Aggregate (NA). Similarly, the basic concrete properties like, compressive strength, workability etc. are studied for the different combinations of RCA with NA.

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Evaluation of an experimental mix proportion study and ...

2.2.Experimental mix design method applied to the recycled concretes. The recycled concrete experimental mix design in this research was performed according to the method described by Monteiro et al., except for the adaptation made to determine the workability of the mixtures evaluated.Instead of using slump test, as described by the mix design method, in the present work …

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Properties of high-workability concrete with recycled ...

This study presents the effects of recycled concrete aggregate (RCA) on the key fresh and hardened properties of concrete. RCA was used to produce high-workability concrete substituting 0- natural coarse aggregate (NCA) by weight. The slump and

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WORKABILITY STUDY FOR RECYCLED AGGREGATES

These aggregates which are often used in the production of concrete are named as recycled aggregates, mainly obtained from crushed concrete 2) Reasons for Use of Recycled Aggregate It is now widely accepted that there is a significant potential …

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Concrete Based on Recycled Aggregates for Their Use in ...

The outcome of the study shows that the recycled aggregates are more heterogeneous and have a high capacity of water absorption, but which still respects the current standards of concrete. The need for additional water has been observed for recycled aggregates-based concrete so …

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Strength and Durability Evaluation of Recycled Aggregate ...

This paper discusses the suitability of producing concrete with 100 % recycled aggregate to meet durability and strength requirements for different applications. Aggregate strength, gradation, absorption, specific gravity, shape and texture are some of the physical and mechanical characteristics that contribute to the strength and durability of concrete.

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What Is Meant By Workability Of Concrete?

Concrete Workability Definition. The workability of concrete refers to how easily freshly mixed concrete can be placed, consolidated and finished with minimal loss of homogeneity. In other words, it refers to how 'workable' the concrete is, how easily it can be manipulated without its strength being compromised.

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Current Applications of Recycled Aggregates from ...

This is the case with CDW, which is mainly composed of these minerals. These can also include recycled concrete aggregates, especially the fine fraction rich in old, hydrated cement paste and other waste coming from cementitious products . Another field of application of RA is the alkali-activated cement, so-called geopolymers.

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Effects of HPMC on Workability and Mechanical Properties ...

However, the bulk density of IOT as aggregate is too large, which seriously affects the concrete properties. Therefore, in this paper, the effect of hydroxypropyl methylcellulose (HPMC) on the workability, mechanical properties, and durability of concrete …

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Workability Retention and Strength Development of Self ...

This paper presents the results on workability testing as well as strength testing of self-compacting concrete containing partial/full coarse recycled concrete aggregates and ternary blended cement using ultrafine recycled powder (RP) and silica fume (SF).

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Aggregate in Concrete - Concrete Network

Recycled concrete will have a higher absorption and lower specific gravity than conventional aggregates. To produce good quality, durable concrete containing a portion of recycled concrete aggregate often requires trial concrete mixes and close monitoring of the properties of the old recycled concrete, with mix adjustments made, as needed.

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(PDF) Effects of HPMC on Workability and Mechanical ...

Therefore, in this paper, the effect of hydroxypropyl methylcellulose (HPMC) on the workability, mechanical properties, and durability of concrete …

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Performance of Recycled Aggregate Concrete

showed that the workability of recycled aggregate is lower than the workability of natural aggregate concrete,the slump test was about 1.0cm slump for 60 % coarse recycled aggregate concrete and increases as the percent of recycled aggregate decreases . The compressive strength of recycled aggregate concrete with 60 % recycled aggregate, is

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Aggregates for Concrete - Memphis

Recycled concrete, or crushed waste concrete, is a feasible source of aggregates and an economic reality, especially where good aggregates are scarce. Conven-tional stone crushing equipment can be used, and new equipment has been developed to reduce noise and dust. Aggregates must conform to certain standards for

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