Ir. Tang is a very experienced civil engineer.  He graduated from the University of Hong Kong in 1981.  Since then, he has worked in the Highways Department of the Government of Hong Kong Special Administrative Region for over 30 years and retired some years ago in the position of Chief Engineer.  He continues to be very active in his career and has joined the Civil Engineering and Development Department taking charge of several construction projects as a Project Team Leader.
 
Mr. Tang is particularly experienced in the maintenance of highway infrastructures, including pavement and bridges.  He took lead in reviewing guidelines and promoting the use of new materials and products for improving the operation of infrastructures.

Ir. CM Tang

Civil Engineering and Development Department, HKSAR Government, Hong Kong

Abstract

Low-Density Engineered Cementitious Composite (LD-ECC) was developed in Hong Kong to address key technical limitations of conventional lightweight foamed concrete, including brittleness, high water absorption and permeability, cracking, and variability in production quality.

Through engineered mix design, LD-ECC can achieve a density as low as about 650 kg/m³ while exhibiting notable engineering strength, high compressive ductility, high fatigue resistance, good crack control, self-healing capability, good pumpability and near self-compaction. Its post-peak compressive strain reaches approximately 8.8%, which enhances material robustness and its ability to accommodate possible deformation due to ground settlement. Importantly, LD-ECC can be produced and delivered through an established ready-mixed concrete QA/QC system, enabling reliable application in full-scale construction.

At Shap Pat Heung Interchange, the use of LD-ECC enabled a lightweight embankment to replace a conventional reinforced-concrete box structure thereby substantially reducing slope and foundation loading. Its pumpability and notable early-age strength, together with the use of precast concrete panels as permanent formwork, further simplified construction and reduced high-risk and labour-intensive activities.

The project demonstrates how advanced material can enable a fundamental change in infrastructure design and construction. Following the successful application of LD-ECC, CEDD and the Building Technology Research Institute are collaborating to develop technical guidelines to facilitate wider and more optimised use of LD-ECC in future engineering works.