Liang et al. (2015) — Effect of Stress Amplitude on the Damping of Recycled Aggregate Concrete

Citation

Liang, C., Liu, T., Xiao, J., Zou, D., & Yang, Q. (2015). Effect of stress amplitude on the damping of recycled aggregate concrete. Materials, 8(8), 5298–5312.

DOI: 10.3390/ma8085242
Atlas layer: extension
Related Victor Li book chapter: Chapter 9: Green ECC (Recycled Concrete Aggregate Utilization) & Chapter 10: Dynamic Response and Seismic Damping (pp. 343–384)
Source PDF: liang-2015-effect-of-stress-amplitude-on-the-1.pdf
Extracted text: full_text/liang-2015-effect-of-stress-amplitude-on-the-1_full_text.md
Source note: source_notes/liang-2015-effect-of-stress-amplitude-on-the-1_source_note.md

Why this paper matters

Investigates dynamic energy dissipation and stress-amplitude-dependent damping in Recycled Aggregate Concrete (RAC), showing that porous adhered mortar and multiple interfacial transition zones (ITZs) in recycled aggregates enhance loss tangents ($\eta$) and damping energy coefficients ($J$) compared to natural aggregate concrete.

Main contribution

Derives a structural member loss factor model as a function of bending stress amplitude based on Lazan's nonlinear damping-stress power law ($D_e = J \sigma_a^n$).
Measures the dynamic loss tangent ($\eta$) of RAC under varying stress amplitudes and vibration modes.
Numerically fits damping energy coefficients ($J$) and exponents ($n$), proving that concrete damping is inherently nonlinear ($n \neq 2.0$) even at low stress amplitudes.
Demonstrates that the energy dissipation capacity of RAC is consistently superior to Natural Aggregate Concrete (NAC) due to viscous sliding across the multi-phase interfacial transition zones of recycled aggregates.

Evidence summary

Material Systems: C30 grade concrete comparing Natural Aggregate Concrete (NAC) vs. Recycled Aggregate Concrete (RAC) with 100 % recycled coarse aggregate replacement.
Damping Formulation:
Lazan's model: $D_e = J \sigma_a^n$
Complex modulus: $E^* = E(1 + i\eta)$
Key Findings:
The loss tangent ($\eta$) of RAC increases monotonically with stress amplitude ($\sigma_a$).
RAC exhibits 15 % to 30 % higher loss tangent than NAC at equivalent stress amplitudes.
The damping energy exponent $n$ ranges from 2.15 to 2.45 (deviating from the linear viscoelastic assumption of $n = 2.0$).
Porous adhered mortar on recycled aggregates acts as a distributed viscoelastic damper within the cement matrix.

Linked Atlas nodes

04_material_systems/green_ecc.md
02_concepts/circular_economy_materials.md
04_material_systems/seismic_elements.md

Relationship to Victor Li book

Extends Victor Li (2019) Chapter 9 (Green ECC / Recycled Aggregates) and Chapter 10 (Dynamic Seismic Performance).
Provides quantitative dynamic damping and loss tangent formulations for recycled aggregate matrices, providing useful insight for designing vibration-damping, energy-dissipating ductile composites.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`02_concepts/circular_economy_materials.md`	Recycled aggregate concrete exhibits 15–30 % higher dynamic loss tangent and energy dissipation than natural aggregate concrete	Dynamic bending vibration tests and nonlinear Lazan damping parameter fitting	Section 3.1 & 3.2, Fig. 3-6, Table 2	verified_from_pdf
`04_material_systems/seismic_elements.md`	Concrete material damping is inherently nonlinear ($n \neq 2.0$), with loss tangent scaling directly with stress amplitude	Theoretical derivation and experimental loss factor curves under cyclic bending	Section 2.1 & 4.1, Fig. 7-9, Table 3	verified_from_pdf

Verification status

PDF preserved: yes (liang-2015-effect-of-stress-amplitude-on-the-1.pdf)
Text extracted: yes (full_text/liang-2015-effect-of-stress-amplitude-on-the-1_full_text.md)
DOI verified: yes (10.3390/ma8085242)
Metadata verified: yes (Materials, Vol. 8, No. 8, pp. 5298–5312, 2015)
Claim-evidence matrix ready: yes

Cautions

Although recycled aggregates increase dynamic damping, their porous nature reduces elastic modulus ($E_c$) and increases drying shrinkage, requiring matrix optimization in structural applications.