Trial Piles with High Percentage GGBS

With a view to reducing carbon emissions, there is a pressing need to promote wider application of low-carbon concrete in construction works. The use of Ground Granulated Blastfurnace Slag (GGBS) as a supplementary cementitious material has been proven effective in reducing the total carbon emission of the concrete production process. While the application of GGBS concrete is not uncommon in the construction of superstructure and precast facades, it is rare to see the use of GGBS concrete in piling works nowadays in Hong Kong. Recent communications with relevant stakeholders revealed a general lack of knowledge of the effects of using GGBS concrete, especially those with high percentage of GGBS, in the construction operation and quality control of piling works. In order to collect more field data and site operation observations in respect of adopting high percentage GGBS in piling works, two full-scale trial piles were constructed with over 75% GGBS replacement level. The entire construction process was carefully monitored and recorded, together with a well-designed testing and monitoring plan, to identify any potential issues during site operation and quality control, and to gain better understanding of the performance of GGBS concrete in-situ. The successful completion of these trial piles would provide technical evidence to support a wider application of GGBS concrete in piling works, thus contributing to the achievement of carbon neutrality in Hong Kong.