Alkali Activated Concrete (AAC) is an alternative kind of concrete that uses fly ash as a total replacement for ordinary Portland cement. Fly ash combined with alkali solution and cured at high temperature react to form a binder. Four point bending tests on a full scale reinforced beams made with AAC are described in this paper. The beam length was 5000 mm and the cross section was 200 mm x 300 mm. Companion small material specimens were cast with the aim of properly characterizing this new tailored material both in compression and in tension. The AAC consisted in fly ash (408 kg/m3), water (35 kg/m3), sand 0-4 mm (647 kg/m3) and coarse aggregate 6-10 mm (1201 kg/m3); alkaline solution consisting in sodium hydroxide (41 kg/m3, 8M) mixed with sodium silicate (103 kg/m3). The maximum aggregate size was 10 mm; fly ash was type F, containing a maximum calcium content of 2%. The ratio l/f.a between liquids and fly ash was equal to 0.44. After a rest period of 2 days, the beam was cured at 60 °C for 24 hours. Data collected and critically discussed included beam deflection, concrete strains, crack width, compressive and tensile strength, elastic modulus and free shrinkage.
EXPERIMENTAL STUDY OF ALKALI ACTIVATED CONCRETE: STRUCTURAL APPLICATIONS
MINELLI, Fausto;MONFARDINI, Linda
2015-01-01
Abstract
Alkali Activated Concrete (AAC) is an alternative kind of concrete that uses fly ash as a total replacement for ordinary Portland cement. Fly ash combined with alkali solution and cured at high temperature react to form a binder. Four point bending tests on a full scale reinforced beams made with AAC are described in this paper. The beam length was 5000 mm and the cross section was 200 mm x 300 mm. Companion small material specimens were cast with the aim of properly characterizing this new tailored material both in compression and in tension. The AAC consisted in fly ash (408 kg/m3), water (35 kg/m3), sand 0-4 mm (647 kg/m3) and coarse aggregate 6-10 mm (1201 kg/m3); alkaline solution consisting in sodium hydroxide (41 kg/m3, 8M) mixed with sodium silicate (103 kg/m3). The maximum aggregate size was 10 mm; fly ash was type F, containing a maximum calcium content of 2%. The ratio l/f.a between liquids and fly ash was equal to 0.44. After a rest period of 2 days, the beam was cured at 60 °C for 24 hours. Data collected and critically discussed included beam deflection, concrete strains, crack width, compressive and tensile strength, elastic modulus and free shrinkage.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
