physiochemical reactions in recycle aggregate concrete

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Physio-chemical reactions in recycle aggregate concrete ...

2009-4-30  This paper has studied the physio-chemical reactions of cement paste around aggregate for normal aggregate concrete (NAC) and recycled aggregate concrete (RAC) mixed with the normal mixing approach (NMA) and the two-stage mixing approach (TSMA) by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM).

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Physio-chemical reactions in recycle aggregate concrete

Four kinds of physio-chemical reactions have been recorded from the concrete samples, including the dehydration of C (3)S (2)H (3), iron-substituted ettringite, dehydroxylation of CH and development of C (6)S (3)H at about 90 degrees C, 135 degrees C, 441 degrees C and 570 degrees C, respectively.

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Physio-chemical reactions in recycle aggregate concrete ...

Four kinds of physio-chemical reactions have been recorded from the concrete samples, including the dehydration of C 3 S 2 H 3, iron-substituted ettringite, dehydroxylation of CH and development of C 6 S 3 H at about 90 °C, 135 °C, 441 °C and 570 °C, respectively. From the DSC results, it is confirmed that the concrete samples with RA ...

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Physio-chemical reactions in recycle aggregate concrete ...

2008-7-15  Physio-chemical reactions in recycle aggregate concrete. Tam VW 1, Gao XF, Tam CM, Ng KM. Author information. Affiliations. 1 author. 1. Griffith School of Engineering, Griffith University, PMB 50 Gold Coast Mail Centre, QLD 9726, Australia. ORCIDs linked to this article. Tam V, 0000-0002 ...

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Physio-chemical reactions in recycle aggregate concrete ...

Request PDF Physio-chemical reactions in recycle aggregate concrete a b s t r a c t Concrete waste constitutes the major proportion of construction waste at about 50% of the total waste generated.

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Physio-chemical reactions in recycle aggregate concrete ...

Tam et al. [14, 6] reported that because of the large amount on mini-cracks in the recycled aggregate, the concrete samples with recycled aggregate substitution had lower values of physiochemical ...

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Physio-chemical reactions in recycle aggregate concrete

This paper studies the physio-chemical reactions of Accepted 8 July 2008 cement paste around aggregate for normal aggregate concrete (NAC) and RAC mixed with normal mixing Available online 15 July 2008 approach (NMA) and two-stage mixing approach (TSMA) by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM).

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Physio-chemical reactions in recycle aggregate concrete -

Abstract. Concrete waste constitutes the major proportion of construction waste at about 50% of the total waste generated. An effective way to reduce concrete waste is to reuse it as recycled aggregate (RA) for the production of recycled aggregate concrete (RAC).

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Physiochemical characterization of coarse aggregates in ...

2013-6-1  The specification of RCA for concrete applications has recently been introduced through the revised Qatar construction standards (QCS) in (Section 5: part 2.9 (concrete)).This section stipulated that recycled concrete should confirm to BS 8500 part 1 and part 2 specifications (BSI, 2002a, BSI, 2002b) or ACI 555R ().Moreover, in part 6 (i.e. property requirements) subsection 6.2.3, Portland ...

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(PDF) Recycled concrete aggregates - ResearchGate

This article presents freeze-thaw (F/T) resistance of concrete containing recycled concrete aggregate (RCA). RCA percentages of 15%, 30%, 45%, and 60% were replaced by natural aggregate.

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Physio-chemical reactions in recycle aggregate concrete -

Abstract. Concrete waste constitutes the major proportion of construction waste at about 50% of the total waste generated. An effective way to reduce concrete waste is to reuse it as recycled aggregate (RA) for the production of recycled aggregate concrete (RAC).

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(PDF) Effect of Recycled Coarse Aggregate on the ...

values of physiochemical reactions than ... Physio-chemical reactions in recycle aggregate concrete. ... The volume of voids and water absorption of recycled aggregate concrete are 2.61 and 1.82% ...

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(PDF) Physiochemical characterization of coarse aggregates ...

In addition, recycled concrete aggregates (RCA) are produced since 2009 as a result of the extensive construc-. tion and demolition activities. It is estimated that around 20,000 tons of ...

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A Review on Alkali-Silica Reaction Evolution in Recycled ...

2020-6-9  materials Review A Review on Alkali-Silica Reaction Evolution in Recycled Aggregate Concrete Miguel Barreto Santos 1, Jorge De Brito 2,* and António Santos Silva 3 1 School of Technology and Management, Polytechnic of Leiria, Campus 2—Morro do Lena—Alto do Vieiro, 2411-901 Leiria, Portugal; [email protected]

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(PDF) Recycled concrete aggregates - ResearchGate

This article presents freeze-thaw (F/T) resistance of concrete containing recycled concrete aggregate (RCA). RCA percentages of 15%, 30%, 45%, and 60% were replaced by natural aggregate.

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Utilization of recycled concrete aggregates for light ...

2019-12-10  Recycled concrete aggregate inclusion in clay soil leads to higher compressive and shear strength. • Recycled concrete aggregate addition to clay soil reduces deformability and settlements. • Clay soil modified with 15% recycled concrete aggregate is strong enough to

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Performance of concrete with recycled aggregates

2008-6-2  standards (valid up to concrete with a compressive strength of about 65 MPa) allow for a replacement of 20% (m/m) of natural primary aggregates by either mixed recycled aggregate or concrete recycled aggregates, without the need for additional performance based tests. Mixed recycled aggregates are

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Recycled Concrete Aggregate Research Papers - Academia

This paper is the outcome of experiments on the shear performance of reinforced concrete beams with approved composite-recycled aggregates. The strength grade of composite-recycled aggregate concrete (CRAC) was between 30 MPa and 60 MPa. The shear span-to-depth ratio varied from 1 to 3.

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Recycled concrete as an aggregate for concrete—a review ...

The present state of knowledge on the use of recycled concrete as an aggregate in new concrete is reviewed and suggestions made as to what further work is necessary before a proper assessment of the material can be made. Where crushed uncontaminated concrete is used the properties of the material as an aggregate and the basic engineering characteristics of the concrete made with it are well ...

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Influence of the amount of recycled coarse aggregate in ...

2012-1-1  The mix design of the concrete was done according to the DoE method, which targeted a compressive strength of 25 MPa at the 28th day .The mixture compositions of all mixes are presented in Table 2.There are notably, five types of mixtures prepared by replacing the coarse aggregate with the RCA at 0%, 15%, 30%, 60% and 80% of the total coarse aggregate content.

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MITIGATING ALKALI SILICATE REACTION IN RECYCLED

2020-1-28  Figure 1-1 Recycled Aggregate Usage.....5 Figure 1-2 Recycled Aggregate Sample from a Concrete Slab.....8 Figure 1-3 Polished Concrete Sample with ASR Gel.....10 Figure 2-1 Expansion versus time for ASTM C 1260 (natural blue

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The Chemical-Mineralogical Characterization of Recycled ...

The incorporation of a recycled concrete aggregate (RCA) as a replacement of natural aggregates (NA) in road construction has been the subject of recent research. This tendency promotes sustainability, but its use depends mainly on the final product's properties, such as chemical stability. This stu

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alkali aggregate reaction Topic - American Concrete Institute

2021-7-1  Alkali-aggregate reactions can be either alkali-carbonate reactions (ACRs) or alkali-silica reactions (ASRs). In ACR, the reaction is between the alkalies (sodium and potassium) and certain carbonate rocks, particularly calcitic dolomite and dolomitic limestones, present in some aggregates. In ASR, the reaction is between alkalies and certain siliceous rocks or minerals, such as opaline chert ...

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Mitigating Alkali–Silica Reaction in Concrete Containing ...

This work involves research on the use of fly ash to mitigate alkali–silica reaction (ASR) in concrete made with recycled concrete aggregate (RCA) that comes from concrete with a known ASR history. Modified ASTM C 1260 and C 1567 with different aggregate grading showed that a 25% cement substitution with a Class F fly ash controlled the expansion under 0.10% at 28 days.

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Mitigating Alkali–Silica Reaction in Concrete Containing ...

2018-12-10  This work involves research on the use of fly ash to mitigate alkali–silica reaction (ASR) in concrete made with recycled concrete aggregate (RCA) that comes from concrete with a known ASR history. Modified ASTM C 1260 and C 1567 with different aggregate grading showed that a 25% cement substitution with a Class F fly ash controlled the ...

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A COMPARATIVE STUDY OF CONCRETE WITH USING

2016-9-9  concrete it is possible to produce recycle aggregate as of similar quality as the natural aggregate (song, et.al, 2009). The compressive strength elastic modulus of recycled aggregate concrete are also lower about 15% to 20% than the natural aggregate concrete. These can be rectified by the addition of fibre to the recycled aggregate concrete ...

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Permeability of Concrete with Recycled Concrete Aggregate ...

The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete

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Alkali silica reaction in concrete induced by mortar ...

The concentration of alkalis on the surface of recycled aggregates- ITZ and the presence of reactive sand in the mortar adhering to the recycled aggregate induce an alkali-silica reaction in 6-month concrete. The existence of this reaction is confirmed by environmental scanning electron microscopy (ESEM) and

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Environmental Considerations in Concrete Recycling

2017-3-29  Concrete Recycling • Breaking, removing and crushing hardened concrete from an acceptable source. • Old concrete pavements often are excellent sources of material for producing recycled concrete aggregate (RCA). • This webinar focuses primarily on RCA from existing pavements (not mixed CD waste). 6

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Recycled Aggregates from Construction Demolition Wastes ...

The concrete aggregate that contains 95% of crushed concrete is called as recycled concrete aggregates. And if the aggregate used in the concrete is 100% crushed, it is called as recycled aggregates. The construction and demolition waste in its original

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