Title: New Developments in Superplasticizers for Lightweight Concrete

Author(s): M. Berra, G. Ferrara, G. Mantegazza, and A. Sereni

Publication: Symposium Paper

Volume: 119

Issue:

Appears on pages(s): 557-582

Keywords: adsorption; air-entraining agents; blast furnace slag; compressive strength; flexural strength; fly ash; lightweight concretes; lightweight aggregate concretes; mortars (material); permeability; water; plasticizers; silica fume; strength; workability; Ma

DOI: 10.14359/2559

Date: 9/1/1989

Abstract:
Structural lightweight concrete is becoming more and more important in building practice as such material can provide mechanical and durability performances like normal weight concrete with higher strength-density ratio. A special superplasticizing admixture able to improve the lightweight concrete workability at very low water-cement ratio, avoiding the segregation problems, has been developed. The considerable advantages of this admixture, in comparison with traditional superplasticizers (ASTM C 494, Type F), are emphasized with workability and mechanical tests on standard mortars made with artificial lightweight fines obtained from sintered fly ash particles or natural sand, two types of cement (blast furnace cement or a mix of portland cement and fly ash), and different silica fume percentages. Water permeability and vacuum water absorption tests on lightweight mortars have also been performed. Finally, the properties of total lightweight concretes made incorporating the new admixture, blast-furnace cement in varying amounts, and silica fume and sintered fly ash lightweight aggregates have been evaluated.