Reactive powder concrete with lightweight aggregates: Fid-Bau Portal

Reactive powder concrete with lightweight aggregates

Grzeszczyk, Stefania / Janus, Grzegorz

Highlights • Lightweight RPC water absorption is mainly determined by RPC matrix water absorption. • EPS surface modification by SP improves its introduction to RPC mix. • Aggregate surface microstructure has also influence on the lightweight RPC strength.

Abstract The paper presents test results of lightweight concretes obtained by introduction of lightweight aggregates: Pollytag, expanded clay aggregate and expanded polystyrene beads (EPS) in quantity from 30 vol% to 60 vol% to the RPC mix. It was demonstrated that addition of the expanded clay aggregate allowed to obtain lightweight RPC with the compressive strength from to 75.2 MPa to 64.5 MPa, and the flexural strength from 12.4 MPa to 12.9 MPa with the aggregate content from 30 vol% to 60 vol%, respectively. In case of Pollytag addition, the compressive strength was from 67.9 MPa to 52.9 MPa and the flexural strength from 11.4 MPa to 9.4 MPa. Whereas concretes with addition of expanded polystyrene beads reached the compressive strength from 50.1 MPa to 32.8 MPa, and the flexural strength from 9.7 MPa to 7.2 MPa respectively. Water absorption of lightweight concretes obtained is approx. 3.0% for RPC with expanded clay aggregate (and it is comparable to RPC without the lightweight aggregate), for RPC with Pollytag approx. 4.0%, and for RPC with EPS it reaches 4.8%. Water absorption of RPC with lightweight aggregates is much lower than absorption of aggregates, which is 8.8% for expanded clay aggregate and 10.1% for Pollytag respectively, and it does not depend on the quantity of aggregate used. The fact that RPC with the expanded clay aggregate reached the highest strength and the lowest water absorption was explained by placement of the concrete mix in large pores on the aggregate surface, and thus reinforcement of the contact between the lightweight aggregate and RPC matrix.