Humidity Effect on the Photocatalytic Activity of Sustainable Cement-Based Composites

Ayat H. Mahdi*, Riyad H. Al Anbari, Maan S. Hassan
Civil Engineering Department, University of Technology (10066), Baghdad, Iraq



In this study, a side-by-side comparison was performed to examine the effects of nano-TiO2 (nT) on the photocatalytic activity of Portland cement (PC) mixtures and its effectiveness compared to similar replacement percentages of micro-TiO2 (mT), both of which were 100% anatase.


Cement paste specimens were prepared by progressive cement replacement with nT or mT. To simulate the effect of humidity in different seasons, the PC specimens were subjected to different moisture conditions, including normal conditions with 50% relative humidity (RH), saturated conditions with 100% RH, and oven-drying conditions with 0% RH. Their photochemical reaction (i.e., gas removal ability) with TiO2 was evaluated and compared with the control specimens. Furthermore, the self-cleaning ability of the mixtures was examined by applying a drop of methylene blue dye to the specimen surface; differences in dye discolouration with time under different illuminations were noticed.

Results and conclusion:

This paper describes the results of an attempt to understand the effect of humidity on the photocatalytic performance of PC composites that incorporate TiO2. The results show that PC mixtures modified with nano titanium are more effective in hot and dry conditions. In contrast, micro titanium mixtures appear to be favourable for wet conditions. Furthermore, the particle size (micro versus nano), matrix voids and absorption values of the cement-TiO2 composite were identified as the key factors affecting the photocatalytic performance.

Keywords: Cement paste, Photocatalytic, Self-cleaning, Sustainability, Titanium, Weather conditions.

Abstract Information

Identifiers and Pagination:

Year: 2018
Volume: 12
Publisher Item Identifier: EA-TOCIEJ-2018-52

Article History:

Received Date: 18/08/2018
Revision Received Date: 15/10/2018
Acceptance Date: 18/10/2018
Electronic publication date: 30/10/2018
Collection year: 2018

© 2018 Mahdi et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Correspondence: Address correspondence to this author at the Civil Engineering Department, University of Technology (10066), Baghdad, Iraq; E-mails:,