Estimation of drying time of fresh concrete slabs: a comparative study

Abstract

Purpose

The purpose of this study is to attempt to compare experimental results for a number of models for the prediction of the drying time of new concrete floors. The investigated methods are the table method, the Swedish Concrete Association (SCA) method and the free computer programme TorkaS 3.2.

Design/methodology/approach

The comparison is based on moisture measurements of four different floor specimens. The specimens have different ratios (w/c = 0.38, 0.6 and 0.7).

Findings

The results show that there is a good agreement between the table method and the measured values on the specimens with high water-cement ratio (w/c = 0.6 and 0.7). However, the deviation becomes greater at lower water-cement ratio (w/c 0.38). TorkaS also resulted in a good agreement with the measurements. However, it is noted that as the drying time increases, the programme exhibits a slow dehydration trend at higher w/c ratios. The SCA method shows various results within the permissible deviation. Moreover, the moisture distribution in concrete with high w/c ratios is found to be mainly influenced by moisture diffusion and little by self-desiccation.

Research limitations/implications

This study is limited to concrete slabs that are drying from one side in an enclosed building with an heating, ventilation and air conditioning (HVAC) system operating normally. Moreover, this study concerns concrete without special additives (e.g. silica fumes), which can be used in some specific cases to accelerate or retard the hydration (cure) process.

Practical implications

These compared methods are used widely in Sweden; therefore, it will be interesting to understand their applicability range. Another focus in this paper is to investigate how the effect of self-desiccation of concrete is related to the w/c ratios, taking into consideration the result of these prediction models.

Social implications

The paper can suit academic researchers, as well as the commercial industries, in a sense that the comparative study will pave a way to the best method to be used for drying time estimation.

Originality/value

The paper contains new information and could be useful to researchers and commercial industries.

Citation

Hassan, O.A.B. and Anderstedt, R. (2017), "Estimation of drying time of fresh concrete slabs: a comparative study", Journal of Engineering, Design and Technology, Vol. 15 No. 2, pp. 134-148. https://doi.org/10.1108/JEDT-02-2016-0011