Macro-defect free cements - Influence of poly(vinyl alcohol), cement type,and silica fume

Macro-defect free cements were prepared using the following variables: proc essing (calendering and hand-mixing), poly(vinyl) alcohol (with different m olecular weight and hydrolysis degree), cement (portland type I and slag-mo dified), and additions of silica fume. The results show that better process ing is achieved by calendering the fresh paste and using poly(vinyl alcohol ) with low hydrolysis degree and low molecular weight. Vickers hardness mea surements indicate that materials prepared using portland type I cement are not significantly affected by humidity. Addition of silica fume lowers the acid resistance of these materials, suggesting that silica fume acts as an inert filler. (C) 1999 Elsevier Science Ltd. All rights reserved.