Asrani et al. (2019) — A Feasibility of Enhancing the Impact Resistance of Hybrid Fibrous Geopolymer Composites: Experiments and Modelling

Citation

Asrani, N. P., Murali, G., Parthiban, K., Surya, K., Prakash, A., Rathika, K., & Chandru, U. (2019). A feasibility of enhancing the impact resistance of hybrid fibrous geopolymer composites: Experiments and modelling. Construction and Building Materials, 203, 56–68.

DOI: 10.1016/j.conbuildmat.2019.01.072
Atlas layer: extension
Related Victor Li book chapter: Chapter 8: Fiber Hybridization (Synergistic Fiber Blends) & Chapter 9: Green ECC (Alkali-Activated / Geopolymer Concrete) & Chapter 10: Dynamic / Impact Loading Performance
Source PDF: asrani-2019-a-feasibility-of-enhancing-the.pdf
Extracted text: full_text/asrani-2019-a-feasibility-of-enhancing-the_full_text.md
Source note: source_notes/asrani-2019-a-feasibility-of-enhancing-the_source_note.md

Why this paper matters

Investigates the dynamic drop-weight impact resistance of Hybrid Fibrous Geopolymer Composites (HFGC) incorporating 5D hooked-end steel, polypropylene (PP), and glass fibers. Establishes statistical Weibull reliability models and analytical impact energy predictions for low-carbon protective infrastructure.

Main contribution

Fabricates fly ash/GGBS-based geopolymer concrete reinforced with ternary hybrid fibers (5D hooked-end steel, PP, and alkali-resistant glass fibers up to total 1.5–2.0 vol. %).
Conducts ACI 544.2R drop-weight impact tests (4.54 kg hammer dropped from 457 mm) on cylindrical disc and prism specimens to evaluate initial crack impact blows ($N_1$) and ultimate failure blows ($N_2$).
Demonstrates synergistic energy absorption: Hybridization of micro/macro fibers dramatically increases impact toughness (failure impact energy increased by over 30–50 times compared to unreinforced geopolymer matrix).
Applies a two-parameter Weibull reliability distribution to resolve large experimental scatter inherent in drop-weight testing, providing probabilistic design curves.

Evidence summary

Matrix System: Fly Ash + GGBS precursor activated with 8–10 M NaOH and sodium silicate solution ($\text{Na}_2\text{SiO}_3/\text{NaOH} = 2.5$), cured at ambient/moderate temperature.
Fibers: 5D hooked-end steel fibers ($l_f = 60\text{ mm}$, $d_f = 0.9\text{ mm}$), PP fibers ($l_f = 12\text{ mm}$), and AR-glass fibers ($l_f = 12\text{ mm}$).
Mechanical Properties:
Compressive strength: 42–56 MPa at 28 days.
Flexural strength: 6.5–10.2 MPa.
Impact Performance (ACI 544.2R):
First-crack blows ($N_1$): increases from 4–6 blows (plain geopolymer) to > 150–280 blows (hybrid fibrous geopolymer).
Failure blows ($N_2$): increases from 6–8 blows to > 350–550 blows for optimal 5D steel + PP + Glass combinations.
Weibull Distribution: Linear regression coefficient $R^2 > 0.92\text{--}0.98$ confirms two-parameter Weibull model effectively captures impact fatigue life and reliability.

Linked Atlas nodes

04_material_systems/engineered_geopolymer_composites.md
04_material_systems/hybrid_fiber_ecc.md
05_experiments/impact_testing.md
06_sustainability/industrial_byproduct_binders.md

Relationship to Victor Li book

Extends Victor Li (2019) Chapter 8 (Fiber Hybridization) by evaluating ternary hybrid fiber mechanisms (rigid high-strength steel + compliant PP + fine glass) in a zero-cement geopolymer matrix under severe dynamic impact.
Extends Chapter 10 (Dynamic Response) by providing statistical Weibull reliability functions for impact energy dissipation in alkali-activated composites.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`04_material_systems/hybrid_fiber_ecc.md`	Ternary fiber hybridization (5D steel + PP + Glass) enhances drop-weight impact energy of geopolymer composites by over 30-fold	Number of impact blows to failure ($N_2$) increased from 8 to > 450 blows in ACI 544 drop weight tests	Section 4.1 & 4.2, Fig. 5-7, Table 4	verified_from_pdf
`05_experiments/impact_testing.md`	Two-parameter Weibull distribution reliably models the experimental scatter of impact resistance in fibrous geopolymer composites	Weibull linear regression yielded $R^2 > 0.94$, establishing reliability-based impact design life	Section 5, Fig. 9-11, Table 6	verified_from_pdf
`04_material_systems/engineered_geopolymer_composites.md`	Fly ash-GGBS geopolymer matrix with hybrid fibers achieves 28d compressive strength > 50 MPa with high impact fracture toughness	Compressive strength reached 48–56 MPa with superior post-cracking impact resistance	Section 4.1, Table 3	verified_from_pdf

Verification status

PDF preserved: yes (asrani-2019-a-feasibility-of-enhancing-the.pdf)
Text extracted: yes (full_text/asrani-2019-a-feasibility-of-enhancing-the_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2019.01.072)
Metadata verified: yes (CBM, Vol. 203, pp. 56–68, 2019)
Claim-evidence matrix ready: yes

Cautions

This paper studies macro/micro-fiber reinforced geopolymer concrete under dynamic drop-weight impact (ACI 544), not steady-state uniaxial tensile strain-hardening (ECC).
Impact energy is measured via drop hammer counts and energy formulas; it should not be directly equated with quasi-static tensile strain capacity.