The hygrothermal assessment of cement-ash-based mortar

Barbora Krejcirikova,Pawel Wargocki,Jakub Kolarik,Carsten Rode,Ruut Peuhkuri

doi:10.1088/1742-6596/2069/1/012193

Barbora Krejcirikova, Pawel Wargocki + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/2069/1/012193

Copy DOI

Abstract

Cement is the second most consumed substance by weight in the world, after water. The growing demand for reduced emissions of CO2 urges the cement industry to find materials with a low CO2 footprint, which calls for cement substitution. An assumption of the study has been that sewage sludge ash (SSA), an industrial by-product, can be applied as a potential cement substitute in cement-based materials without compromising material performance. The study investigated the effect of partial replacement of cement by SSA in mortar on hygrothermal properties of mortar. Two sewage sludge ashes originated from wastewater treatment plants located in the Greater Copenhagen area, Denmark. SSAs consisted of larger particles compared to cement particles; thus cement-ash-based mortar resulted in more porous structures compared to cement-based mortar. The higher porosity was responsible for a decrease of the thermal conductivity of the mortar. Significant differences were recognized in sorption isotherms of individual components, i.e. cement and ashes. However, their effect on the sorption isotherms of the mortars was minor.

Highlights

Negative environmental effects and overexploitation of available resources is a prevailing and extensive problem faced by the construction industry
The growing demand for reduced emissions of CO2 urges the cement industry to find materials with a low CO2 footprint, which calls for cement substitution
Two sewage sludge ashes originated from wastewater treatment plants located in the Greater Copenhagen area, Denmark

Summary

Introduction

Negative environmental effects and overexploitation of available resources is a prevailing and extensive problem faced by the construction industry. Cement is the second most-consumed substance by weight in the world, after water [1], and during its production 900 kg of CO2 are emitted per ton of cement [2]. The growing demand for reduced emissions of CO2 urges the cement industry to find materials with a low CO2 footprint, which calls for cement substitution. In order to achieve feasible rates of cement substitution, it is necessary to introduce new supplementary cementitious material (SCM), which is readily and possibly locally available. Sewage sludge ash (SSA) could be such a viable resource. The assumption of the study states that SSA, as an industrial by-product, can be applied as a potential cement substitute in cement-based materials without any compromise on the material performance

Materials and Methods

Results and Discussion

Conclusion