Lightweight ECC Technology

Lightweight concrete with densities between 900 and 1600 Kg/m3 has been used in various structural and non-structural applications, offering considerable weight saving. By adding ductility, lightweight ECC can further broaden the applicability. Four approaches to achieving lightweightedness for a Polyvinyl Alcohol (PVA) fiber ECC are explored in this project, including uses of air-entrainment admixture, polymeric micro-hollow-bubble, natural lightweight aggregates perlite and glass micro-bubbles. Density, uniaxial tensile behavior, and compressive strength of 15 mix designs are examined. The experimental results show that multiple cracking and strain hardening can be achieved by all these approaches; however, tensile and compressive strengths and robustness of strain capacity significantly vary with content and type of lightweight “filler” used. Mixes by adding glass micro-bubbles with controlled size distribution exhibit more superior mechanical performances than other approaches. For example, tensile strength of 4 MPa with strain capacity above 4% is achieved in a lightweight PVA-ECC with 2% fiber volume fraction at a density of 1450 Kg/m3, along with a compressive strength of 41 MPa.

SEM Picture of Lightweight ECC Microstructure

Tensile Behavior of Two Versions of Lightweight ECC

Lightweight ECC Canoe