PSI - Issue 37

João Custódio et al. / Procedia Structural Integrity 37 (2022) 644–651 João Custódio et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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temperature regime recorded onsite in the worst-case scenario, as presented in section §4.2, up to about 120 hours, following the same previous trend until reaching 20 ºC.

0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0

In situ temperature Test temperature

Temperature, ºC

0

50

100 150 200 250 300 350

Time, hours

Fig. 1. Heat treatment and in-situ temperature record.

3. In-situ testing campaign 3.1. Casted elements

The in-situ testing campaign aimed at recording the concrete temperature evolution of a viaduct deck section, during its casting. Fig. 2 shows a schematic of the assessed element ’s section. The temperature probes were placed in duplicate, at the longitudinal centre of the element, at depths of 0.1, 0.6, and 1.1 m (represented as red coloured circles in Fig. 2). A couple of probes were also left far from the casted concrete to record the environmental temperature.

2.20 m

3.40 m

Fig. 2. Section of the tested structural element.

3.2. Concrete mixtures The concrete mixture applied for casting the deck is presented in Table 2. The concrete was made to a strength class of C40/50. The table also presents the density of each constituent. The cement used was a CEM II-A/L 42.5 R. The coarser aggregate had a maximum particle size of 20 mm. The used superplasticizer (SP) was a high range water reducing admixture applied in a form of a liquid solution of modified polycarboxylates in water, and the plasticizer

(P) was a lignosulphonate-based water reducing admixture. Table 2. Concrete mixture proportioning and materials density (kg/m 3 ). Constituent Cement Fine aggregate 1 Fine aggregate 2

Coarse aggregate 1

Coarse aggregate 2 Water SP

P

Girder deck

350

365

326

596

625

146

2.08 3.45

Materials density

3000

2610

2600

2700

2710

1000 1040 1150