Cement bonded particleboards were manufactured from hornbeam (
Cement-bonded particleboard has been manufactured using conventional technology, where the boards are kept under pressure for consolidation for several hours. The pressure is necessary because the hydration of the cement is a slow process. The cement hardening is usually completed in three to four weeks. The characteristics that make such type of boards desirable to various construction applications are decay and fire resistance and good dimensional stability.
A significant problem however, when
these products are manufactured, is the compatibility of wood with cement. The term compatibility, when applied in the area of
wood-cement composites, refers to the degree of cement setting after mixing
with water and with a given wood in fragmented form. Generally, if the chemical
process of cement hardening is undisturbed by the presence of wood, it is
considered that cement and wood are compatible. On the other hand, if cement hardening is impaired by the presence of
wood, then cement and wood are referred as incompatible [
The hydration tests were
carried out as previously described [
Hornbeam particles that
previously passed the
After 15 minutes of manual mixing, the cement-wood water mixture was
screened onto to a caul. The mat was evenly distributed to provide as uniform a
density as possible and prepressed to a thickness of approximately 50 mm. Cold pressing took
place under an initial pressure of 5 MPa, to a 15 mm thickness, after which the
board was retained in compression for 24 hours. Target board density was 1200 Kg/m3. A total of six boards were made, each
measuring
One way analysis of variance (ANOVA) at 5% level of significance was used to compare the properties of the panels between different wood cement ratios.
60 samples, measuring
The results obtained from the hydration test
are shown in Table
Inhibitory index of hornbeam wood species used in this study. (Standard deviations in parentheses.)
Wood species | Inhibitory index (%) | |
---|---|---|
Without additive | With additive (3% CaCI2) | |
Hornbeam | 39.15(a) (4.3) | −0.92 (0.08) |
(a)Each value represents the mean of four replicates.
The mechanical properties of the boards are presented in Table
Mechanical and physical properties of cement-bonded hornbeam boards. (Standard deviations in parentheses.)
Wood: cement | Density(a) (Kg/m3) | MOR(b) (N/mm2) | MOE(b) (N/mm2) | IB(a) (N/mm2) | TS(a) (%) |
---|---|---|---|---|---|
1 : 3 | 1270 (0.18) | 12.68 (0.5) | 6009.6 (32.1) | 0.35 (0.07) | 1.75 (0.6) |
1 : 4 | 1280 (0.12) | 10.56 (0.8) | 7056.4 (199.3) | 0.56 (0.04) | 0.67 (0.1) |
BISON type HZ | 1.20 | 9.0 | 3000 | 0.40 | 1.2–1.8 |
(a)Each value represents the mean of twelve replicates.
(b)Each value represents the mean of eight replicates.
The results obtained after a 16-week incubation period are presented in Table
Weight loss (WL) of cement-bonded hornbeam boards. (Standard deviations in parentheses.)
Brown rot | White rot | |
---|---|---|
Wood: cement | WL(a) (%) | WL(a) (%) |
1 : 3 | 0.85 (0.07) | −1.88 (0.40) |
1 : 4 | −2.92 (0.20) | −1.45 (0.66) |
(a)Each value represents the mean of twelve replicates.
The aim of this paper was to manufacture wood cement particleboards using particles of hornbeam and to evaluate the mechanical
properties and decay resistance of the boards. Based on hydration tests, it was
found that the mixture of maple-cement can be
classified as moderate inhibition. Two wood: cement ratios were applied in this study, namely, 1 : 3 and 1 : 4, for
the board manufacture. It was found that an increase of cement-wood ratio
resulted in an improvement in all properties examined, except for MOR. All properties of the boards
made from 1 : 4 wood: cement ratio surpassed the minimum requirements set forth
by the building-type HZ code. Boards were exposed to brown and white rot fungi,