PSI - Issue 22

3

Maria da Luz Garcia et al. / Procedia Structural Integrity 22 (2019) 166–170 Maria da Luz Garcia, Rosário Oliveira / Structural Integrity Procedia 00 (2019) 000 – 000

168

Rf, Rc (MPa)

0,0 0,5 1,0 1,5 2,0 2,5 3,0

28 d AHL

56 d AHL

70 d AHL

28 d AWC

56 d AWC

70 d AWC

Fig. 1. Average Values of the Compression and Flexural Strength

Figure 1 presents average values of the Compression and Flexural Strength at 7, 28 and 56 days in order to understand the evolution of resistance. The results of the mechanical strength allow complete mortar hydraulic lime, AHL until after 28 days shows a resistance values lower than the commercial mortar, AWC, but in terms of compressive strength AHL mortar has higher values than those obtained for the commercial mortar from 56 days of age, increasing with age, while in the AWC mortar the compressive strength remains constant after 28 days. 2.3. Capillary water absorption test The capillary water absorption test was performed on 160 × 40 × 40 mm prismatic specimens according to the LNEC Specification E393 and the RILEM TC 116 PCD recommendation in the applicable part. Samples were tested after 42 days (instead of 28 days). Only the test was carried out over a period of 4.5 hours because the absorption curve shows an approximate linear behaviour, so that the absorption coefficient (S) corresponds to the linear gradient obtained by linear regression to the absorption curve, Eq. 1. A = a 0 + S. t 0 . 5 (1) Where: A - water absorption per unit area of the concrete (mg / mm 2 ) S - material absorption coefficient (mg / (mm 2 .min 0.5 )) t - time passed from the initial moment (min) a0 - water initially absorbed by pores in contact with water (mg / mm 2 ) The absorption coefficients were calculated by linear regression from the absorption curves relative to the test specimens for the 270 minutes of assay. All linear regressions corresponded to correlation coefficients above 0.984.

Tab. 1 Average values of water absorption

Absorption of water by immersion at 48 hours

Water absorption by capillarity

S [mg⁄((mm²×√min) )]

∆S [mg⁄((mm²×√min) )]

A (%)

∆A (%)

AHL AWC

1,716 0,893

0,07

26,27 21,25

2,61 2,54

0,022