Development of vegetation concrete technology for slope protection and greening

Abstract

Slope vegetation clearing for urban development purposes often leaves the slope prone to surface erosion prior to revegetation establishment. This study is in response to the requirement of immediate slope protection and revegetation. As no research in Australia exists on vegetation concrete technology, this paper analyses and presents the results of growing various native Australian grass species on porous concrete under different mix compositions. It aimed to determine the feasibility of an integration of vegetation and concrete for use in slope protection, more specifically, explored the effect of a concrete environment on the following Australian native grass species: Themeda trianda, Chloris truncata and Elymus scaber. To enhance the survival of grasses, calcium aluminate cement (CAC) with a lower pH than ordinary Portland cement was used. Additionally, the influence of various fly ash contents on strength characteristics (compressive strength, tensile strength and elastic modulus) of porous concrete was also examined. The growth characteristics of the vegetation concrete grass species were monitored for 8 weeks during which the average grass height, relative coverage and root development were observed. The experimental results showed that the compressive and tensile strengths of the tested porous concrete were comparable and similar to the currently applied slope protection methods. Furthermore, it was evident that Chloris truncata was better adapted to the concrete environment than the other two tested grass species. However, Elymus scaber thrived with a remarkable coverage at high fly ash content, whereas Themeda trianda preferred a lower fly ash content. The results pave the path for further research into this technology and have significant implications for the application of vegetation concrete technology, especially in an Australian context.