The implementation of alkali-activated concrete in jointless ground floors

Abstract

To realise more sustainable industrial ground floors the implementation of alkali-activated concrete is considered for jointless elastically supported ground floors. Such floors are realised with large areas without dilations, the shrinkage reduction is therefore restrained causing cracks to arise at the top surface of the floor. The control of cracking is the governing design aspect for jointless ground floor and is done by a top reinforcement mesh combined with the addition of steel fibres in the concrete mixture. Alkali-activated concrete is a concrete realised without cement and has a reduced CO2 footprint, it can show some beneficial material properties, making it a potential concrete for a more sustainable floor. A parametric study is done and an optimised floor realised in alkali-activated concrete is considered. Crack-width calculations of increased accuracy are performed via bond-slip calculations. These are performed analytically and by finite element analysis done with DIANA. Comparisons show that the so called direct method and DIANA underestimate the crack-widths relative to the more accurate analytically computed results. Additionally, it is found that the improved bond strength of alkali-activated concrete results in smaller crack-widths. It follows that with alkali-activated concrete a jointless floor can be realised in a thinner cross-section and with less steel necessary to control the crack-widths. As a result alkali-activated concrete is suitable to construct more sustainable jointless ground floors.