Rendering Mortars with Low Sand and Cement Content. Incorporation of Sanitary Ware Waste and Forest Biomass Ashes

Catarina Brazão Farinha,Rosário Veiga,Jorge De Brito

doi:10.3390/app10093146

Catarina Brazão Farinha, Rosário Veiga + Show 1 more

Open Access

https://doi.org/10.3390/app10093146

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Abstract

The incorporation of wastes in new materials and products is an emerging trend, reducing virgin materials’ consumption and landfill deposition and the associated environmental impacts. Cement-based mortars can encapsulate some wastes, with the benefits stated above. In three previous researches, it was found that forest biomass bottom ashes (up to 15% by volume of cement), powder of sanitary ware (up to 20% by volume of sand) and sanitary ware particles above 2 mm (100% by volume of sand) can be incorporated in rendering mortars, replacing cement or sand. Several tests were performed, and it was found that each waste’s incorporation presents advantages and limitations, when compared with a reference mortar. In this research, the aim was to take advantage of the best features of each waste, combining them in order to optimize the new mortars’ characteristics. Therefore, mortars with one, two and three wastes were analysed in this research. The ternary mix mortar had a volume of wastes equal to 83%, resulting in a mortar with 15% less cement (by volume) and without any natural aggregate (all replaced with the sanitary ware wastes). The fresh, water and mechanical behaviour of the mortars with and without wastes are presented in this research. It was concluded that it is possible to take advantage of the best features of each waste and achieve mortars simultaneously with high volume of wastes and a better performance than the reference mortar (without wastes).

Highlights

In 2016, the total weight of wastes generated by the EU-28 amounted to 2538 million tonnes [1].Construction and demolition waste represented 36% of the total wastes generated [1] and was still the most pollutant sector
It was noticed that the incorporation of sanitary ware waste as a filler improved the workability of the resulting mortar (SWP mortar), allowing a decrease of the w/b ratio from 1.3 to 0.9 for similar consistency, when compared with the REF mortar (Table 1)
The sanitary ware powder (SWP) waste filled the voids between the particles of sand, decreasing the water needs of the mortars [6]

Summary

Introduction

In 2016, the total weight of wastes generated by the EU-28 amounted to 2538 million tonnes [1]. Construction and demolition waste represented 36% of the total wastes generated [1] and was still the most pollutant sector. It was responsible for producing materials that have great impacts on the environment, such as cement. According to the European Cement Association, one tonne of CEM II produced releases 738 kg of CO2 into the atmosphere [2]. In order to achieve the aims proposed, Directive 2008/98/CE of the EU set up a minimum rate of reuse, recycling or other material recovery [4], 70% (by weight) for construction and demolition waste

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Conclusion