Lightweight Concrete Produced Using a Two-Stage Casting Process

• Published in: Materials Vol. 8; no. 4; pp. 1384 - 1397
• Main Authors: Yoon, Jin Young, Kim, Jae Hong, Hwang, Yoon Yi, Shin, Dong Kyu
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.03.2015; MDPI
• Subjects: aggregate; Aggregates; Cement; Cements; Concrete mixing; Density; grout; Lightweight; lightweight concrete; Lightweight concretes; Mechanical properties; Particle size; Placing; Strength; two-stage concrete; Volume fraction; Weight reduction; lightweight concrete; volume fraction; two-stage concrete; grout; aggregate
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma8041384

The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregates in a frame and then filling in the remaining interstitial voids with cementitious grout. The casting process results in the lowest density of lightweight concrete, which consequently has low compressive strength. The irregularly shaped aggregates compensate for the weak point in terms of strength while the round-shape aggregates provide a strength of 20 MPa. Therefore, the proposed casting process can be applied for manufacturing non-structural elements and structural composites requiring a very low density and a strength of at most 20 MPa.