Assessment of recycling process induced damage sensitivity of recycled concrete aggregates

Nagataki, Shigeyoshi; Gökçe, Ahmet; Saeki, Tatsuhiko; Hisada, Makoto

doi:10.1016/j.cemconres.2003.11.008

Cited by 331 publications

(119 citation statements)

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“…Previous work has shown that the amount of crushing performed on an RCA can affect its reactivity (Shehata, Christidis et al, 2010;Adams, Ideker et al, 2012). This was attributed to the amount of adhered mortar on the aggregate (Shehata, Christidis et al, 2010;Adams, Ideker et al, 2012), which is reduced as the level of crushing is increased (Nagataki, Gokce et al, 2004). These past results show that the amount of adhered mortar can affect the level of reactivity in an aggregate, and subsequently may affect the efficacy of an SCM to mitigate ASR.…”

Section: Mitigation Studymentioning

confidence: 71%

“…Work by Shehata et al also evaluated this problem by performing ASTM C1260 testing on RCA that had gone through one level of crushing, and then a second set of testing on RCA that had been left over from the first crushing (slightly larger particles) and crushed again. That study found that the amount of crushing can have a significant impact on the reactivity of aggregates (Shehata, Christidis et al, 2010), which was attributed to the loss of adhered mortar during successive crushing (Nagataki, Gokce et al, 2004). To investigate this, material from the crushing facility produced from the four exposure blocks from Ottawa (Alberta, Bernier, Potsdam and Springhill RCAs) that met the ASTM C1260 gradations ( < 4 mm) was put aside and labeled as "crusher's fines."…”

Section: Aggregate Preparationmentioning

confidence: 99%

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Durability Assessment of Recycled Concrete Aggregates for Use in New Concrete Phase II

Ideker¹

2014

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Type of Report and Period Covered14. Sponsoring Agency Code 15. Supplementary Notes 16. Abstract: This Phase II investigation into the durability of new concrete incorporating recycled concrete aggregates (RCA) focused on several goals: 1) Provide corroboration of results obtained in Phase I for a multi-laboratory study related to assessing alkali-silica reactivity (ASR) of RCA in accelerated laboratory tests; 2) Investigate the efficacy of mitigation methods to control ASR in concrete containing potentially reactive RCA; 3) Establish long-term data through placement of concrete blocks containing RCA in an outdoor exposure site in Laramie, WY; and 4) Survey state DOTs and other transportation agencies about their perceptions and usage of RCA ASR in concrete within their agency and how that may be improved through the use of a database tracking tool. From Phase II the following main conclusions were drawn: 1) The coefficient of variation limits in ASTM C 1260-07 do not apply to concrete mortar bars incorporating RCA. It is recommended that further testing, using different RCA and more laboratories (at least six), should be completed before a new standard for RCA and/or incorporation of RCA into the current ASTM C 1260 test may be allowed. 2) Generally, as the replacement level of RCA was reduced, the amount of SCM needed to control deleterious ASR also decreased for the RCA sources investigated in this study. 3) Ternary blends containing metakaolin resulted in the most significant decrease in expansions compared to the mixtures with no SCMs.The results of the transportation agency survey showed the following: 1) A vast majority of agencies believed that sustainability was important to their agency and that it was addressed in a clear and meaningful way. 2) A majority, 54%, of agencies believed they had specific guidance for the use of RCA in new concrete; however, only 15% believed that there was strong information from the federal level about the use of RCA in new construction. 3) Of all respondents, 77% indicated their agency was concerned about alkali-silica reaction in concrete in general for their agency. 4) The biggest barriers to using RCA were noted as concerns about quality, a lack of standards and specifications, and unclear guidance on the testing of RCA. 5) The biggest concerns specific to a source of RCA when considering it for use in new construction were increased shrinkage concerns, ASR and residual chlorides. 6) The most sought-after information about a potential RCA source when considering it for use were the existing condition of the RCA when it was taken out of service, the reason it was taken out of service, whether repairs were performed to the structural element taken out of service, and the age of the RCA. 17.

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Section: Mitigation Studymentioning

confidence: 71%

Section: Aggregate Preparationmentioning

confidence: 99%

Durability Assessment of Recycled Concrete Aggregates for Use in New Concrete Phase II

Ideker¹

2014

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“…(4). From these tests, the measured average yielding strength, tensile strength and modulus of elasticity of the rebar was 327MPa, 438MPa and 2.04×10 5 MPa respectively. …”

Section: Specimen Preparationsmentioning

confidence: 99%

“…It may indicate that Equation (1) is also applicable to compression specimens with recycled concrete. The measured residual bearing capacity of RRC specimens after 100 freeze-thaw cycles is listed in Table ( 5). N and N 100 is the average bearing capacity of two specimens before and after 100 freeze-thaw cycles respectively.…”

Section: The Bearing Capacitymentioning

confidence: 99%

“…Till now, a lot of researchers have conducted experimental research on the basic physical property and mechanical behavior of RAC. Olorunsogo and Padayachee [4], Nangataki et al [5], Oikonomou [6], Khatib [7]discovered that the compressive strength, shear strength and tension strength of RAC were much lower than those of NAC. The previous findings mainly focus on the short-term mechanical behaviors of RAC; however, the research on the durability (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Compressive Strength Study on the Freeze-thaw Resistance of Recycled Aggregate Concrete Members

Niu¹,

Wang²,

Zhang³

et al. 2017

TOCIEJ

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Introduction:Freeze-thaw resistance of recycled aggregate concrete with partial or total replacement of recycled aggregate compared with that of natural aggregate concrete was investigated in this paper. Method:Ninety specimens were fabricated to study the influence of different recycled aggregate replacement ratios on the surface scaling, mass loss, and residual compressive strength after 100 freeze-thaw cycles. Results:The experiment results indicate that the type of recycled aggregate and its replacement ratio have significant effects on the freezethaw performance. The cubic compressive strength of recycled aggregate concrete is overall slightly lower than that of normal concrete. After 100 freeze-thaw cycles, the compressive strength decreases and the reduction extent increases with increasing replacement rate of recycled aggregate. The surface scaling of reinforced recycled concrete prisms tends to be more severe with the increase of freeze-thaw cycles. Conclusion:Furthermore, a notable rise in mass loss and the bearing capacity loss is also found as the substitution ratio increases. Under the same replacement rate, recycled fine aggregate causes more negative effects on the freeze-thaw resistance than recycled coarse aggregate.

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Base force element method based on the complementary energy principle for the damage analysis of recycled aggregate concrete

Wang

Peng

Kamel

et al. 2019

Numerical Meth Engineering

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Summary The finite element method (FEM) is an effective approach for exploring the failure mechanism of heterogeneous materials. According to the complementary energy principle, the use of FEM might suffer from several difficulties in terms of keeping the elements and their boundaries balanced, as well as finding interpolation functions. In this study, we introduced an efficient approach to researching the failure mechanism of the material, named base force element method (BFEM), according to complementary energy principle. Specifically, the element compliance matrix of an arbitrary quadrilateral element with four mid‐edge nodes was expressed based on the complementary energy principle. Then, the node displacement was obtained by the governing equation using the Lagrange multiplier method. In addition, both the compliance matrix and the node displacement were represented as explicit expressions without the use of Gaussian integration. A numerical model of the recycled aggregate concrete (RAC) was established according to the Monte Carlo method. A comparative sample of the digital image model was also established using digital image technology. The influences of substituting recycled aggregate and the relative mechanical properties of adhered mortar to those of new mortar on the failure mechanism of RAC were studied. The simulation results indicated that the BFEM is an effective approach to researching the damage mechanism of heterogeneous materials.

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Assessment of recycling process induced damage sensitivity of recycled concrete aggregates

Cited by 331 publications

References 1 publication

Durability Assessment of Recycled Concrete Aggregates for Use in New Concrete Phase II

Durability Assessment of Recycled Concrete Aggregates for Use in New Concrete Phase II

Compressive Strength Study on the Freeze-thaw Resistance of Recycled Aggregate Concrete Members

Base force element method based on the complementary energy principle for the damage analysis of recycled aggregate concrete

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