PSI - Issue 64

H. Varela et al. / Procedia Structural Integrity 64 (2024) 1427–1434 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

1429

3

cement to sand ratio of 1:1.25 and a water to cement (w/c) ratio of 0.45. Sisal fibers (SF) of 13 mm length were added at 0.5% (M1), 1% (M2) and 1.5% (M3) by volumetric fraction (VF) and of 6.5 mm length at 1% by VF (M4).

Reference (M0)

Sisal fiber addition

Fiber 13 mm:

Cement CPII-F40 (high initial strength)

Fiber 6.5 mm o M1 : 0.5 % volume fraction o M2 : 1.0% volume fraction o M3 : 1.5% volume fraction o M4 : 1.0% volume fraction

Natural Sand 0-0.6 mm 1:1.25 (Cem:Sand)

W/C = 0.45

Fig. 1. Composition scheme of mixtures designed for this study.

c) Hardening assesment (conventional vs 3DP)

a) Rheological characterization i) Flow table test

b) 3D Printability evaluation i) Manual extruder

i) Mechanical (14 days)

compression strength (≈ 4x4x8 cm)

Flexural strength (≈ 4x4x16 cm)

3DP specimen

ø 1

ø 2

Manual extrusion

Conventional specimen

(4x4x16mm samples)

Final spread diameters

ii) Cone-penetration test

ii) 3D robotic printer

ii) Physical (≈ 4x4x4 cm)

conventional and 3DP specimens

Time

Open porosity

Capillarity

Depth penetration

95.0 g

115.0 g

Samples stirred and at rest

- Dry, Saturated and Submerged weight

Weight over time

3D printing

.

Fig. 2. Experimental stages and methods used in this study: a) rheological characterization; b) printability evaluation; c) Hardened assessment.

Figure 2 shows the experimental stages completed in the study: a rheological characterization (Fig. 2a), a printability evaluation (Fig. 2b) and a hardened assessment (Fig. 2c). Two experimental methods were used for the rheological evaluation, a flow table test (FTT) and a cone-penetration test (CPT) with a cone geometry of 35 mm height and an angle of 30º. Both tests were used to evaluate initial and over time rheology of samples, accordingly to Bohuchval et al. (2020) and Varela et al. (2023a - 2023b).