PSI - Issue 64

Irene Palomar et al. / Procedia Structural Integrity 64 (2024) 1435–1443 Irene Palomar et al. / Structural Integrity Procedia 00 (2024) 000 – 000

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Fig. 1. Design criteria, components, requirements and experimental program to evaluate bio-based self-modulating mortars.

2.1. Mortars’ design and compositions Mortar compositions are summarized in Table 1. Cement type BL II/B-L 42.5 R and Air lime CL-90S, designated according to UNE-EN 197 – 1 and UNE-EN 459 European standards respectively, were blended and used as mortar binder. Sand with particle size between 2 and 3 mm was used as gap graded aggregate (GGA). Two types of commercial superabsorbent polymers (SAP) were used, one with spherical particle shape, SAP(S), and the other with irregular particle shape, SAP(I), with a water intake in alkaline pH after 10 minutes of 35g/g and 29g/g, respectively. A commercial microencapsulated paraffin wax phase change material (PCM), Micronal ® DS 5040x, with a particle size ca. 50 – 300 μm, bulk density ca. 300 – 400 kg/m 3 and a melting point of ca. 23 ± 1 °C. SAP and PCM where supplied by Master Builder Solutions. Water was added to reach a target flow test diameter of 180 ± 20 mm (plastic consistency).

Table 1. Mortar compositions (kg/m 3 ). Cement Air lime

Sand 2/3

SAP (S)

SAP (I)

PCM (P)

Water *

w/b**

Reference (REF)

230 230 230 230 230 230 230

85 85 85 85 85 85 85

1710 1710 1710 1710 1710 1710 1710

-

- - - -

- - -

250 285 322 362 279 313 313

0.79 0.79 0.86 0.98 0.79 0.86

S-1.0 S-1.5

1

1.50 1.50

S-1.5 + P

93

I-1.0 I-1.5

- - -

1

- -

1.50 1.50

I-1.5 + P 0.86 *Considering both liquid water added and water from components (sand humidity 3% and water intake on alkaline pH after 10 minutes of Spherical SAP 35g/g and Irregular SAP 29g/g) **SAP water intake is not included 2.2. Experimental methods Fresh state mortar characterization comprised workability and early age parameters. Mortar workability was measured using the flow table test to obtain fresh mortar consistency, according to the European standard UNE-EN 1015 – 3. Water to binder ratio (w/b) was adjusted to achieve a plastic consistency. Early age parameters free 93