Composition Design and Performance Evaluation of Non-Autoclaved Cement–Fly Ash Foam Concrete Modified with Wollastonite And Basalt Fiber

The paper presents a scientifically grounded composition-design approach for non-autoclaved cement–fly ash foam concrete modified with wollastonite and basalt fiber. The study is focused on the stabilization of the cellular structure, strengthening of interpore partitions and improvement of the balance between thermal insulation and mechanical performance. A two-stage preparation route was adopted: technical foam was produced separately and then introduced into a cement–fly ash matrix containing dispersed wollastonite and, when required, basalt fiber. The main controlled parameters were water-to-solid ratio, cement-to-fly ash ratio, foam density, wollastonite fraction and dosage, wollastonite fineness, and fiber content. The results indicate that dispersed wollastonite at 1.0–1.5% of binder mass reduces fresh-mixture settlement from 14 mm in the control mixture to about 6 mm and increases the foam stability index to 0.94–0.95 at a specific surface of approximately 300 m²/kg. The most effective method of addition was dry blending with cement and fly ash, which produced a dry density of 532 kg/m³, thermal conductivity of 0.128 W/(m·°C), and 28-day compressive strength of 1.92 MPa. Compared with the control mixture, the combined dispersed-wollastonite and basalt-fiber modification increased 28-day compressive strength by about 48%, reduced drying shrinkage by about 27%, and increased the closed-pore fraction from 46% to 52%.

Foam concrete, cement–fly ash binder, basalt fiber

Ramamurthy, K.; Nambiar, E. K. K.; Ranjani, G. I. S. A classification of studies on properties of foam concrete. Cement and Concrete Composites, 2009.

Nambiar, E. K. K.; Ramamurthy, K. Air-void characterization of foam concrete. Cement and Concrete Research, 2007.

Jones, M. R.; McCarthy, A. Behaviour and assessment of foamed concrete for construction applications. Proceedings of the Institution of Civil Engineers, 2005.

Neville, A. M. Properties of Concrete. Pearson Education, 5th edition.

Taylor, H. F. W. Cement Chemistry. Thomas Telford Publishing.

Mindess, S.; Young, J. F.; Darwin, D. Concrete. Prentice Hall.

ASTM C495/C495M. Standard Test Method for Compressive Strength of Lightweight Insulating Concrete.

Experimental research file: Koytash wollastonite and basalt-fiber modified cement–fly ash foam concrete, unpublished laboratory dataset.