Ultra-lightweight Concrete Containing Expanded Poly-lactic Acid as Lightweight Aggregate

• Published in: KSCE journal of civil engineering Vol. 22; no. 10; pp. 4083 - 4094
• Main Authors: Sayadi, Aliakbar, Neitzert, Thomas R., Clifton, G. Charles, Han, Min Cheol, De Silva, Karnika
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Civil Engineers 01.10.2018; Springer Nature B.V; 대한토목학회
• Subjects: Aggregates; Biopolymers; Calcium; Calcium carbonate; Calcium carbonates; Calcium silicate hydrate; Carbonates; Carbonation; Cement; Chemical reactions; Civil Engineering; Concrete; Concrete aggregates; Concrete mixes; Curing; Curing (processing); Electrical properties; Engineering; Environmental impact; Gels; Geotechnical Engineering & Applied Earth Sciences; Hydration; Industrial Pollution Prevention; Lactate; Lactic acid; Lightweight concretes; Mechanical properties; Microstructure; Organic chemistry; Petroleum; Petroleum products; Polylactic acid; Polymers; Products; Structural Engineering; Thermal properties; Thermodynamic properties; Vermiculite; Vermiculites; Water-cement ratio; Weight reduction; 토목공학; lightweight concrete; vermiculite concrete; expanded poly-lactic acid
• ISSN: 1226-7988; 1976-3808
• DOI: 10.1007/s12205-018-1976-4

The environmental impact of using petroleum products has become a serious issue nowadays. This paper is about the possibility of producing ultra-lightweight concrete by using bio-polymer aggregate as a replacement for petroleum polymer. Expanded poly-lactic acid (EPLA) and Expanded Vermiculite (EV) are used as aggregate in producing biopolymer concrete. In total, five concrete mixtures are designed with varying EPLA and EV contents. The cement content and effective water-cement ratio are kept constant. The EV aggregate was replaced with EPLA aggregate in the ratio of 20%, 40%, 60% and 80%. Three types of curing conditions were used. The mechanical properties, thermal properties, electrical properties of biopolymer concrete were assessed and analysed. The microstructure of concrete was assessed after 28-days and one year. It was found that the properties of EPLA concrete are mainly influenced by the volume of EPLA and curing conditions. The chemical reactivity of EPLA significantly changes the hydration products of concrete and causes concrete carbonation as well as the conversion of hydration products to more calcium carbonate. However, at the long-term investigation (after a year) the more C-S-H gel was found. Furthermore, EPLA aggregates shrunk and lost their strength in the alkaline environment of cement.