Recycled Aggregate Characterization Methods_Presentation Conference - PDF document

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/281102581 Recycled Aggregate Characterization Methods_Presentation Conference Paper · August 2015 CITATIONS READS 0 87 1 author: Anette Mueller IAB - Institut für Angewandte Bauforschung Weimar GmbH 101 PUBLICATIONS 333 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Use of CDW as Raw Material View project A book on recycling of recycling of building materials. Very little about waste management and very much about processing and building materials. View project All content following this page was uploaded by Anette Mueller on 20 August 2015. The user has requested enhancement of the downloaded file.

Institut für Angewandte Bauforschung Weimar gemeinnützige GmbH Recycled Aggregate Characterization Methods Prof. Dr.-Ing. habil. Anette Mueller IAB Weimar gGmbH Sao Paulo August 2015

Construction and Demolition Waste and Recycling Materials in Germany: Quantities and sectors of reuse State of the Art of Quality Control: Methods and results on composition and granulometry Sensor Based Optical Methods: Future alternatives for control of composition and granulometry? Sophisticated Characterization • Recycled concrete aggregates as composite material • Construction and Demolition Waste as feedstock Conclusions 2

1 CDW and Recycling Materials in Germany Amount of Construction and Demolition Waste from different sources 3 Bundesverband Baustoffe – Steine und Erden e.V. Monitoringberichte 1996-2012

1 CDW and Recycling Materials in Germany Amount of material reused in different sectors CDW for filling Price: giving away for free Bundesanstalt fuer Strassenwesen: Jahresbericht 2009/2010. 4 http://www.stadtentwicklung.berlin.de/umwelt/abfall/rc-beton/ TV-Foto/Archiv: Gabi Vogelsberg

2 State of the Art of Quality Control Technical Standards on • Reuse of asphalt in road construction • Reuse of recycled concrete aggregates in road construction • Reuse of recycled concrete as aggregate in structural concrete Environmental Standards on • Reuse of tar containing asphalt • Permitted content of leachable substances in dependence on site conditions P P Permeable layer Impermeable layer RC with low/medium con- RC with minimum tent of leachable matter leachable matter > 1 m > 1 m

2 State of the Art of Quality Control Technical standards for recycled aggregates Composition Granulometric parameters Physical parameters Reuse as base course material in road construction Particle size distribution Material composition Water content Particle shape Finely divided organic Density Content < 0.063 mm constituents Proctor density Content of oversize Resistance to abrasion Portion of crushed particles Freeze/thaw resistance Reuse as recycled concrete aggregate Particle size distribution Material composition Water absorption Particle shape Lightweight organic constituents Density Content < 0.063 mm Content of Resistance to abrasion water-soluble chloride Freeze/thaw resistance − acid-soluble chloride − water-soluble sulfate − acid-soluble sulfate − Total sulfur content 6

2 State of the Art of Quality Control Material composition Particle size and shape Method: Screening Method: Hand sorting of the Method: Particle fraction > 4 mm shape gauge M 1 W L M 2 Percentage passing Shape Index = 100*M 2 /(M 1 + M 2 ) = 100*M L/W>3 /M total Hand sorting of ore acc. to Agricola 1556 7

2 State of the Art of Quality Control Quantity of sample for reliable results Particle size Material composition Threshold [mass-%] Max. Sample size mass ≤ 0.2 ≤ 5 ≤ 10 [mm] [kg] Sample mass [kg] 32 50.9 83.9 3.2 1.5 16 36.0 Number of particles 8 25.5 4/8 + 8/45 4 18.4 122,054 4,648 2,201 + + + 13,832 527 249 8 Diederich, D.: Recycling R'13, Weimar 2013.

2 State of the Art of Quality Control Results on composition taken from quality control protocols of base course materials • Material fulfils the requirements Considerable differences in performance � over- or undervaluation • • Faction < 4 mm is not detected as high as possible ≤ 30 mass-% ≤ 30 mass-% ≤ 5 mass-% ≤ 1 mass-% ≤ 0.2 mass-% 9

2 State of the Art of Quality Control Results taken from quality control of material for recycled aggregate concrete • Material fulfils the requirements • No clear declaration of content either of concrete aggregates or of virgin aggregate � recycling without recycled aggregates possible Type I/Type II ≥ 90 resp. ≥ 70 mass-% ≤ 10 resp. ≤ 30 mass-% ≤ 1 mass-% ≤ 1 resp. ≤ 2 mass-% ≤ 2 cm³/kg 10

2 State of the Art of Quality Control Results on particle sizes taken from quality control of base course material • Material fulfils the requirements Percentage passing • Particle size distribution follows the Gates-Gaudin-Schuhmann-Function x: particle size [mm] x max : maximum particle size [mm] • Material specific influences undetec- n: distribution exponent [-] table under industrial conditions x max = 56 mm, n = 0.55 x max = 32 mm, n = 0.4 11

3 Sensor Based Optical Methods as Alternative Sensor based optical methods as future alternative for control of composition and granulometry? Combination of optical measurement of color, NIR spectrum (available) and size, shape (available) • Size, shape, color, and NIR spectra � material composition • Size and shape � particle size distribution, particle shape index http://www.haver-partikelanalyse.com/formanalyse-von-partikeln/ 12 Mogensen GmbH & Co. KG, Wedel, Germany.

3 Sensor Based Optical Methods as Alternative Detection of kind of material: Investigations of identification by means of near infrared spectra Masonry rubble Clay brick Rubble of aerated auto- claved concrete ~ 1930 nm Pure AAC Calcium silica brick ~ 1430 nm Concrete rubble Gravel Concrete Lightweight concrete 13 Escher, M.: Diplom Thesis, Weimar 2010.

3 Sensor Based Optical Methods as Alternative Detection of particle size Jaw crusher - splintery • Defined as diameter of circle with equal area and platy particles • Cubic particles: Good agreement • Platy particles: Correction necessary Impact crusher - cubic particle 14 Stark, U.; Mueller, A.: AufbereitungsTechnik 45 (2004) 6, S. 6 - 16.

3 Sensor Based Optical Methods as Alternative Detection of particle shape • Defined as ratio length (Feret diameter) Direction of to width (maximum secant) measurement x Fe • Ratio x Fe /x S of particles generated with the jaw crusher higher than with the impact crusher • Correaltion between shape index SI and ratio x Fe /x S x S x 15 Stark, U.; Mueller, A.: Beton (2006) 9, S. 390 – 397.

3 Sensor Based Optical Methods as Alternative Automated quality assurance of material composition, particle size and shape as future option for recycling? Advantages/Disadvantages • Sufficient large sample mass during reasonable time measurable • Higher frequency of quality control • No subjective influences, especially on detection of kind of material • Mass of material fractions not directly measured but calculated from granulometric parameters and typical densities • Fraction < 4 mm not measurable Research for deepening of knowledge is required! 16

4 Sophisticated Characterization Recycled concrete aggregate as composite material Arguments against civil engineer approach: • Counterparties in concrete are cement paste and aggregates (and ITZ), not Mortar mortar and aggregates • Cement paste content in mortar can vary Civil engineer approach • Mechanical properties of mortars are not far from concrete Composite Pure aggregate 17

4 Sophisticated Characterization Cement Material scientist approach paste Composite Clear characterization of recycled concrete aggregates by the properties of the main components (natural aggregates + cement paste) and the content of the cement paste Pure aggregate 18

4 Sophisticated Characterization Methods for determination of cement paste content As acid soluble content: • Moebius, Schnell/2001: Solubility in hydrochloric acid (10%) similar to Standard DIN 52170 • Engelsen et al./2009: Solubility in concentrated nitric acid similar to Standard Nord Test Build 437 • Weimann/2009: Solubility in hydrochloric acid (10%) similar to Standard DIN 52170 • Belin et al./2014: Solubility in nitric acid solution (1/50) As difference of the quartz content up to 100%: • Florea, Brouwers/2013: Quartz content by phase transition of α -SiO 2 to β - SiO 2 measured by thermogravimetric (TG) and differential scanning calorimetry (DSC) 19

4 Sophisticated Characterization Comparison of cement paste content measured with the different methods • Similar results and trends for the dependency of the cement paste content on the particle size • Both methods not suitable for concrete with calcitic aggregates 20

4 Sophisticated Characterization Binary state diagram for recycled concrete aggregates BAST Jahrbuch 2008 21