Re ECF Project: 2010-31

Project Title: Utilizing recycled waste glass in architectural mortar with self-cleaning and anti-bacterial function

Applicant: Prof. POON Chi-sun of Hong Kong Polytechnic University

Total Approved Grant: $782,900 (ECF & WWGF: 50/50)

Duration: 1/1/2012 to 31/3/2014

Project Status/Remarks: Completed

Scope:
The project aims to utilize the recycled glass cullet to achieve high aesthetic quality and photocatalytic performance without compromising the mechanical properties of architectural mortar for building materials application. The project objectives are:

  • to assess the feasibility of using up to 100% recycled glass as natural aggregate for production of architectural mortar;
  • to study the mechanical and durability properties of the architectural mortar prepared with recycled glass;
  • to investigate and optimize the particle size of recycled glass used to achieve the desired aesthetical properties;
  • to assess the self-cleaning and disinfecting properties of the architectural mortar produced; and
  • to demonstrate the laboratory production method for applying in industrialized production process.

Summary of the Findings/Outcomes:
The laboratory test results show that increasing recycled glass (RG) content leads to slight reductions in mechanical and durability properties of the architectural mortars. Additionally, glass powers with a particle size less than 150 ┬Ám have been demonstrated to be an alternative to an effective pozzolana (like fly ash and metakaoline) in suppressing alkali-silica reaction (ASR) expansions. Intermixing nano-TiO2 particles in the glass cementitious system can achieve a certain level of photo-catalytic activities. The light-transmitting characteristic of RG allows light to enter a greater depth of the mortar, activating more TiO2 particles. However, the efficiency is limited by the encapsulation of the TiO2 by the hydrated cement paste. To address this problem, dip-coating and spraying TiO2 particles, and applying a TiO2 coating on the surface of architectural mortars and surface layers can greatly enhance the photocatalytic activities. Additionally, several commercially available TiO2 paints have been tested and it was found effective use of them can enhance the photocatalytic activity of the architectural mortars with air pollutant removal, self cleansing and anti-bacterial functions. Introduction of 100% RG in the architectural mortar brings an attractive combination of a high compressive strength and aesthetically pleasing appearance even after exposure to 800°C. In the course of our study, a new molding method has been identified and tested to allow the production of the glass architectural mortar without the use of steel molds to enhance the production efficiency.