Methods of testing the properties of fibre-cement composites

Abstract

The paper deals with process of manufacturing the fibre-cement materials and methods of testing their climatic performance. Basic raw materials for production fibre-cement sheets are cement, cellulose fibers, reinforcing fibers - polyvinyl alcohol (PVA) fibers, filler, additives and water. Production follows the modified Hatschek's technology. The paper described the most important tests for climatic performance: Freeze-thaw test and Heat rain test. The fibre-cement profiled sheets were tested. The Freeze-thaw test includes assessment of frost resistance, precipitated salts efflorescence on the face-side surface, peeling of the coating on the edges, peeling of the coating on the face-side surface, longitudinal cracks in the various locations on the face-side, transverse cracks in the various locations on the face-side, shape deformation, swelling water between the layers of coating and material delamination on the edges. The frost resistance RL for fibre-cement profiled sheets after 100 freeze-thaw cycles was 0.95, when min. RL = 0.70. The fibre-cement profiled sheets were tested to 50 heat-rain cycles. After 50 cycles, the samples were checked for cracking (longitudinal, transverse and at the fixing points), delamination and other visible defects (especially the presence of formed drops on the underside of corrugated sheets). The tested modified recipe of fibre-cement profiled sheet met the Heat rain test requirements.The paper deals with process of manufacturing the fibre-cement materials and methods of testing their climatic performance. Basic raw materials for production fibre-cement sheets are cement, cellulose fibers, reinforcing fibers - polyvinyl alcohol (PVA) fibers, filler, additives and water. Production follows the modified Hatschek's technology. The paper described the most important tests for climatic performance: Freeze-thaw test and Heat rain test. The fibre-cement profiled sheets were tested. The Freeze-thaw test includes assessment of frost resistance, precipitated salts efflorescence on the face-side surface, peeling of the coating on the edges, peeling of the coating on the face-side surface, longitudinal cracks in the various locations on the face-side, transverse cracks in the various locations on the face-side, shape deformation, swelling water between the layers of coating and material delamination on the edges. The frost resistance RL for fibre-cement profiled sheets after 100 freeze-thaw cycles was 0.95, when min. RL = 0.70. The fibre-cement profiled sheets were tested to 50 heat-rain cycles. After 50 cycles, the samples were checked for cracking (longitudinal, transverse and at the fixing points), delamination and other visible defects (especially the presence of formed drops on the underside of corrugated sheets). The tested modified recipe of fibre-cement profiled sheet met the Heat rain test requirements.