Calculating plastic viscosity of self-compacting concrete using V-funnel time: a novel mathematical approach with calibration using coefficient of viscosity
Year: 2025
Type: article
Abstract: The plastic viscosity (µ) of Self-Compacting Concrete (SCC) is a fundamental rheological property governing its flowability, passing ability, and segregation resistance. However, measuring µ typically requires specialised and costly rheometers or viscometers, which are not readily accessible in many developing countries. This limits the widespread evaluation and optimisation of SCC in resource-constrained settings. While some alternative methods to determine µ exist, they often depend on regression, iteration, or elemental modelling, and may lack comprehensiveness and general applicability. To address this gap, the present study explores the potential of the standardized EFNARC V-funnel test that is widely used for assessing SCC flow, as a practical and direct approach to estimate µ. A mathematical model was derived by analysing the laminar flow of SCC through the V-funnel, relating the V-funnel time (T) to µ and the unit weight of the mix. The model was validated through experimental testing on 44 diverse SCC mixes. A parameter coefficient of viscosity “C” was introduced, defined as the ratio of rheometer recorded plastic viscosity (µ rh ) to theoretically calculated SCC viscosity (µ th ). The results revealed values of C ranging from 0.80 to 1.80 with a mean value (C m ) of 1.43. The model-calculated values C m .µ th and rheometer-recorded values µ rh exhibited a good agreement with R 2 , Kling Gupta Efficiency ( KGE) and Mean Absolute Error ( MAE ) values of 0.9253, 0.4640 and 16.78 Pa.s, respectively. However, model reliability was further evaluated separately for the mix series incorporating different binder compositions. The local C values for each of these series were recorded as C ml . Using C ml instead of C m improved the model performance. The C ml .µ th and µ rh exhibited better correlation with R 2 and KGE values of 0.9728 and 0.5596, respectively, while showing a reduced MAE to 14.45 Pa.s, thus confirming model reliability. These results confirm that the proposed V-funnel-based approach, when calibrated with appropriate viscosity coefficients, provides a reliable and accessible method for estimating µ in SCC. Future work may focus on mapping C m and C ml values for different SCC types and charting them to broaden the model’s applicability.
Source: Discover Civil Engineering
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4416104166