Related Experiment Video
Updated: Jul 7, 2026

Sandy Soil Improvement through Microbially Induced Calcite Precipitation (MICP) by Immersion
Published on: September 12, 2019
The application of waterworks sludge ash to stabilize the volume of cement paste
1Department of Civil and Ecological Engineering, I-Shou University, 1, section 1, Hsueh-Cheng Rd., Ta-Hsu Hsiang, Kaohsiung County, Taiwan, 84008, ROC. hlluo@isu.edu.tw
Abstract:
In order to extend the recycling of waterworks sludge to engineering applications, this paper addresses the influence of nano-SiO2 on incinerated waterworks sludge ash (IWSA) cement paste attacked by sulfate. Tests were performed such as length measurement for volume change, compressive strength, weight loss, and micro-structural testing using scanning electron microscopy (SEM). The results indicate that when a portion of the cement in the paste was replaced by IWSA, the IWSA diluted the cementitious material C3A, and filled the capillary pores in the hardened paste. Moreover, since IWSA has potential pozzolanic activity, it can chemically react with Ca(OH)2 crystals in the paste and can consequently improve the resistance of the paste to sulfate attack. Test results also show that due to the fully developed pozzolanic effect of IWSA, the major reaction products of sulfate attack, gypsum and ettringite, were clearly reduced. Hence, the expansion rate in length decreased with the increase of IWSA replacement. Furthermore, the addition of nano-SiO2 to IWSA cement paste can also reduce the length expansion rate.
More Related Videos
Related Concept Videos
Porosity in Cement Paste
The balance of water to cement in the mix is critical—it...
Soundness of Cement
Types of Cement II
Design Example: Managing Concrete Workability
To address...
Pozzolans
Fly ash is a...
Hydration of Cement

