Investigation of the Leaching Behaviour of a Novel Cement-Polyurethane Hybrid Material for Waterproofing Purpose

Abstract

A novel cement-polyurethane hybrid material invented to stop massive water ingress during e.g. tunnel construction is presented in this study. A special emphasis is put on the leaching behaviour and the environmental impact of the material. For this purpose, a batch test as worst-case scenario and a tank leaching test were used to compare different material combinations. Besides sum parameters like pH value, major elements from cement and organic species were analysed in the leachates. Simulations about the release behaviour of ionic species as well as the total organic carbon were performed. Release was governed by surface wash-off effects for all species except for Al which was controlled by diffusion. Leaching of major elements correlated with the amount of ground granulated blast furnace slag added to substitute ordinary Portland cement. Total organic carbon content was measured, and the cumulative value was in the range of 83 to 49 mmol/m² after 64 days of leaching. All investigated parameters were below the threshold values governed by German authorities. In addition, ecotoxicological tests with earthworm species (Enchytraeus albidus) have been performed to explore the impact of the leachates on the environment. While in pure eluate tests the early age leachates showed toxic effects, in soil and sand tests the buffering function plays a key role to prevent possible hazardous effects.

from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2w2xmWc