PSI - Issue 23

Małgorzata Lenart et al. / Procedia Structural Integrity 23 (2019) 113 – 118 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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and 14 day granules was determined before further tests. It was 4.3% for 1-day granules and 2.0% for 14-day granules. 24-hour water absorption (WA24) of 14-day granulate, determined according to EN 1097-6, was 6.8%. The degree of cement dehydration in the case of 1-day granulate was about 38% and in the case of 14-day granulate about 85% according to the manufacturer's test results. It is worth mentioning that the same type of cement was used to make the tested mortars (control – C and with the addition of granules – A1  B3) (see Table 1).

a

b

Fig. 1. Granules appearance: (a) before sieving, (b) after sieving: 1-day granules (left) and 14-day granules (right).

Fig. 2. The appearance of 4 mm grain granules.

Table 1. The properties of cement used to prepare granules as well as tested mortars. Properties Mean value 2-days Compressive Strength [MPa] 28.1 28-days Compressive Strength [MPa] 55.9 Initial Setting Time [min] 183 Specific Gravity [g/cm 3 ] 3853 SO 3 content [%] 2,81 Cl - content [%] 0,058 Loss on Ignition [%] 3,14 Insoluble Residue [%] 0,76

2.2. Preparation of mortars with granules

The shrinkage tests were carried out on seven types of mortars: the control one and mortars with variable granulate amount of 10%, 25% and 50%. As already mentioned, granulate used to produce these mortars was 1 or 14 days old. Mortars with a larger amount of granulate had less fluidity, therefore a plasticizing admixture (polycarboxylic ether) was used to stabilize the consistency of fresh mortars. The amount of admixture was selected to achieve a mortar consistency of about 140  160 mm determined by flow table according to EN 1015-3. The mortar was made on the basis of cement CEM I 42.5R. The properties of the cement used are listed in table 1. The composition of tested mortars per batch intended for making 3 beams 40 × 40 × 160 mm is shown in table 2. The mortars were made in accordance with the procedure described in EN 196-1.