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THE WOOD WOOL CEMENT BOARD

INDUSTRY IN THE PHILIPPINES


This site describes the wood wool cement board industry in the Philippines.

Description of the product, its properties, and the chronological sequence of its development are

briefly outlined. Producers of boards as well as the raw materials used and the manufacturing

process they follow are illustrated. Board supply and demand is briefly discussed.


The Product

History

Manufacturing Plants

list of plants

Supply and Demand

Raw Materials

wood, cement, accelerator

Manufacturing Process

Board Properties

MOR, MOE, TS, WA, Biodeterioration and Fire resistance,

Thermal resistance, Sound absorption, Environment friendliness

Applications

Research and Development

References

Useful Links

Acknowledgement


 

The Product

What is wood wool cement board?

Wood wool cement board (WWCB) is a panel product consisting of long thin strands of wood that are bonded together with an inorganic binder such as Portland cement. Panel dimensions are mainly 610 mm wide (2ft) and 2440 mm (8ft) long and thickness ranging from 8 to 50 mm. It is usually produced in densities from 450 to 900 kg/cu.m. Board density is higher for thinner boards.

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Brief History of the Wood Wool Cement Board Industry in the Philippines

The use of shredded wood, termed as wood wool or excelsior as reinforcement for inorganic binders dates back to the beginning of the 19th century. Gypsum- and magnesite-bonded excelsior boards were manufactured in 1905 and 1915, respectively (Kossatz et al. 1983). However, the first commercial production of wood wool cement boards (WWCBs) started and was patented in Austria in 1927. In the Philippines, research to explore the suitability of indigenous wood species for the manufacture of WWCBs began almost half a century later by the Forest Products Research and Development Institute (FPRDI), a research and development arm of the Department of Science and Technology (DOST). A pilot-scale manufacturing plant was established at the Composite Products Section (CPS) of the Institute to conduct applied research on the utilisation of Philippine wood species and simulate manufacturing conditions at a commercial level. Availability of a vast array of other by-products such as sugarcane bagasse, rattan shavings, coconut coir fibre, and tobacco stalks also prompted researchers to investigate the potential of these agricultural residues as raw material for cement-bonded boards. WWCBs of commercial size were manufactured using the pilot plant and were used to construct a 36-square metre model house in the FPRDI compound in 1986. Several other model houses were constructed in other parts of the country. These demonstration houses showcase the feasibility of using WWCBs as alternative construction material specifically for cost-effective houses. In addition to these model houses, FPRDI promoted the technology through the conduct of investors fora that attracted a number of entrepreneurs to invest in the commercial manufacture of boards.

The first commercial-scale WWCB plant was established in Central Luzon in the late 1980s. More plants were established in the early 1990s due partly to the large demand for the product in meeting housing requirements of the country, approximately 3.85M units (NHA, 1993). Currently, the housing unit deficit is around 3.3M (Tuazon, 1999). After about a decade, the industry has expanded to its current number of 14 WWCB plants.

 

Picture courtesy of Dr. Phil Evans

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The Manufacturing plants

The list of established WWCB plants as well as cement-bonded boards manufactured from other ligno-cellulosic materials is presented in Table 1. The raw material they process depends on their availability and accessibility. In the southern part of the country for example, plantation species such as yemane (Gmelina arborea) are widely planted and are therefore used by most of the plants that produce WWCBs. On the other hand, in Central Luzon, plants use industrial by-products such as sugarcane bagasse and rattan shavings that are available in substantial quantities. Consequently, such cement-bonded boards can be manufactured and sold at a lower price. In northern Luzon, countless hectares of tobacco leaves are harvested each year, the stalks, being by-products are utilised in combination with shredded wood to form WWCBs.

The WWCB manufacturing plants are of relatively small to medium scale capacity. They are strategically located in various parts of the country as presented in Fig. 1. Most of the plants are evenly distributed in the Luzon and Mindanao islands while there are only two plants manufacturing boards in the Visayas group of islands.

 

Table 1. Cement-bonded board plants established in the Philippines.

 Company/Location

 Estimated Plant Capacity

(No. of boards per annum)*

 Raw Material
 WWCB Plants    

 1. Aptech Manufacturing Corp.**

Angeles, Pampanga

 60,000
 plantation wood/ rattan wastes

 2. Fabricemtech

Lucena, Quezon

 40,000
 plantation wood/ sugarcane bagasse

 3. GC Enterprises

Zamboanga

 150,000
 yemane/ palo verde

 4. San Nicolas Multi-purpose Coop.

Candon, Ilocos Sur

 20,000
 giant ipil-ipil & tobacco stalks

 5. R-II Builders

National Capital Region

 40,000
 plantation wood

 6. Cemboard Systems Inc.***

Lipa, Batangas

 700,000
 yemane

 7. Phela Resources

General Santos City

 60,000
 yemane

 8. Boalan Agri-Resources

Zamboanga del Sur

 120,000
 yemane/ palo verde

 9. Cruzayco Corp.

Kabankalan, Negros Occ.

 60,000
 yemane

 10. Cagayan WoodWorks Manfg Corp.

Solana, Cagayan

 450,000
 yemane

 11. Caraga Women's Cooperative

Butuan City

 40,000
 yemane/ rattan waste

 12. Earn Corporation

Bay, Laguna

 40,000
 yemane

 13. Villarica Forest Products

Samal Island, Davao

 40,000
 yemane

 14. Zementboard Cooperative

Koronadal, South Cotabato

 40,000
 yemane
 Total

 1,860,000
 
 Plants Manfg Boards Using Other Raw Materials    

 15. Versaboard Enterprises

Angeles, Pampanga

 40,000
 sugarcane bagasse

 16. Alenter Cane Corp.

Cebu

 40,000
 rattan wastes

 17. Lemn Products Int'l/Victorians Mktg.

Imus, Cavite

 40,000
 rattan wastes
 Total

 120,000
 
 Grand Total

 1,980,000
 

* 12-mm thick board basis

** Pioneer manufacturing plant

***Under construction

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Supply and Demand

Assuming that all these plants are producing boards at their estimated plant capacity, the total annual board production is approximately 1.98M. The annual housing requirement of the country is around 633,726 units (source: Housing and Urban Development Coordinating Council). If a 36-sq.m. house requires 124 boards, the yearly production of boards can only be sufficient for only 15,968 units which is a mere 2.5 percent of the total dwelling needs annually. The Cement-Bonded Board Manufacturers Association of the Philippines (CBBMAP) estimated that it would require 275 small-scale plants to satisfy the annual housing requirements (Bello et al. 1995).

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Raw Materials

Wood

Simple sugars inhibit the setting of cement and hence wood-cement composites can only use certain wood species that have a low concentration of simple sugars. In general, hardwoods are more incompatible with cement than softwoods due to their higher content of hemicelluloses, phenolic substances and sugars than softwoods. Thus, many hardwoods in their natural state are unsuitable for wood-cement composite manufacture (Weatherwax and Tarkow 1964). The Philippines however, has more hardwood species growing in plantations. The major plantation wood species that has been used for WWCB manufacture are the fast-growing trees such as giant ipili-ipil (Leucaena leucocephala Lam de Wit) and yemane (Gmelina arborea R.Br.). Giant ipil-ipil has also been used by some plants but cautious selection of the age of the tree is necessary because of the extreme hardness of the heartwood of older trees. Yemane, on the other hand, has been increasingly utilised mainly due to its availability, ease in shredding and the light colour of the wood which produces a lighter coloured board - a feature preferred by many end-users. Strictly, however, yemane is not suitable for the manufacture of wood-cement composites in its natural state. Manufactured WWCBs from freshly-felled five-year old yemane cannot be handled immediately after pressing as a result of manufacturing boards without prior wood treatment (Cabangon 1997). To minimise the inhibitory effect of simple sugars to cement setting, the shredded wood is soaked in tap water prior to manufacture. In this manner, compatibility of the wood with cement is greatly enhanced.

Cement

Any material that has adhesive and cohesive properties can be described as cement. The cements used for WWCB manufacture are hydraulic cements, that is, they set and harden upon the addition of water. There are two main types of cement marketed in the Philippines, ordinary Portland cement (OPC) and Pozzolan cement. OPC has been used in most of the plants due to its faster setting time. Studies showed that WWCBs manufactured using Portland cement gave higher bending strength and water resistance than those bonded with pozzolan cement tested after 28 days of curing (Mallari et al. 1994). Various types of cement differ in their setting time, however, this can be significantly increased using chemical accelerators.

Cement-setting accelerator

Chemical accelerators play an important role in the hydration process of cement. These additives when incorporated in wood-cement composites enhance the hydration characteristics of cement and cement-based composites. They rapidly cure the cement and minimize the inhibitory effect of low-molecular weight extractives found in most wood species and thus, increases board strength. A number of chemical accelerators have been found useful to increase the setting of cement. The most common accelerators are calcium chloride and aluminum sulphate because of their availability, efficacy and relative low cost. In the Philippines, the former is more commonly used because of its higher solubility in water which consequently, does not delay board manufacture.

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Manufacturing Process

WWCBs can be manufactured using simple equipment for low-capacity plants to the most sophisticated versatile plants of high capacity. Regardless of plant capacity, however, the basic steps in board manufacture remain the same, as follows:

Materials Preparation

Logs, tops and branches of trees with minimum diameter of 100 mm are cut into 400-mm long billets. If necessary, the billets are debarked manually using a sharp bolo. They are then shredded along the grain using a shredding machine to produce wood wool or excelsior with dimensions of 0.4 x 4 x 400 mm. The wood wool is soaked in tap water for 12 to 24 hours to leach out low molecular weight carbohydrates that could inhibit the normal setting of cement. The soaked wood wool is then air-dried to equilibrium moisture content of about 18 percent. Wood wool, cement, water and accelerator are weighed using a weighing scale and top loading balance. Their respective weights depend on the desired board density, thickness, water/cement ratio and wood/cement ratio. Water/cement (w/w) ratio can vary from 0.8 to 1.0 while the minimum wood/cement ratio (w/w) is 45/55.

Blending and Mat-forming

Shredded wood, water (with dissolved accelerator), and cement are mixed in their respective order, using a mechanical mixer. Mixing is done until all the shredded wood is thoroughly coated with the cement paste. The cement-coated shredded wood is hand-formed in most of the plants (see picture below) in a rectangular mold to form a mat. The mold is a detachable 305 x 660 x 2490 mm wooden frame placed over a caul plate lined with plastic sheets. The mold is removed prior to pressing of boards.

Picture courtesy of Dr. Phil Evans

 

Pressing

The formed mat on top of the caul plates are stacked on top of each other in batches of 10 to 20, depending on the final thickness of the boards. Board compaction of the stack is done using a 60 to 100 tonne capacity hydraulic press. Wooden or steel stoppers corresponding to the desired final thickness of the boards are placed on the longer side of the caul plate and then pressure (approx. 3000 psi) is applied until the caul plates meet the stoppers between them. Pressure is maintained for 18 to 24 hours using a steel clamping system. After clamping, the stack is removed from the press to accommodate another batch of boards.

Curing/Conditioning

Each manufactured board is taken out of the caul plate and allowed to stand vertically on its longer side, in between wooden stickers, in a dry, well-ventilated and adequately-protected area for three weeks. The boards are trimmed to their final board dimension and are then stacked on top of the wide surface of each other at an adequate height for storage or delivery. At this stage, boards can be randomly sampled from the stacks to evaluate their physical and mechanical properties.

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Board Properties

WWCBs have been shown to have the essential properties to satisfy the various economic, production, construction, cultural, safety and health requirements of the Philippines (Pablo et al. 1994). Given the chronic housing shortage being experienced by the country, the need for suitable alternative construction material is imperative. The high cost of traditional building materials is considered to be one of the major constraint to alleviate the problem in the perennial housing backlog because the majority of the people who need these houses are the ones who cannot afford financially to own one. The board is relatively cheap since indigenous raw materials are used and it does not necessarily require expensive and sophisticated equipment. The process of board manufacture is simple and therefore the need for highly skilled personnel is not essential. Board application is not complicated as it is a workable material. One of the major drawbacks suggested by end-users of WWCBs is the roughness of the surface of the boards. This undesirable feature however, can be regarded as advantageous since mortars can readily be applied to the boards to give their final finish, making them workable boards. WWCBs can readily be painted, fastened and sawn and is easy to use as pre-fabricated structures in order to reduce construction time. It does not require special equipment to handle boards during construction.

Cultural preference is another important factor since it indicates the acceptance of the product as alternative construction material. Houses formed out of concrete are the preferred type in the country. Most houses in the urban and suburban areas of the country are made of concrete while those in rural areas are shanties made of bamboo or wood. Concrete dwellings can therefore be regarded as a status symbol. Being cementitious in nature, WWCBs have become popular as an alternative to concrete. More importantly however, WWCBs performs like concrete and wood. It has been proven to withstand adverse effects of tropical cyclones, seasonal monsoon rains, and high humidity. WWCBs have the required strength as well as the resistance to high humidity in the tropical climate as presented in Table 2.

Table 2. Properties of WWCBs from five manufacturing plants in the Philippines (Eusebio and Cabangon, 1997).

 Company

MOR (MPa)

 MOE (MPa)

 TS (%)

 WA (%)

 A
 3.6  1002  2.76  47.44

 B
 4.5  1837  1.25  28.51

 C
 2.4  718  1.93  75.51

 3.5  1302  0.37  33.67

 E
 5.1  1333  1.37  41.90

Aside from the excellent dimensional stability and acceptable mechanical properties of WWCB, it has also some degree of resistance against combustion and attack of termites and microorganisms such as fungi and decay. It is the presence of cement particles particles in the wood cell wall that provides resistance against microorganisms and reduces combustibility (Parmasweraan 1977). Resistance of WWCB against fungi attack also depends on the alkaline nature of cement since these microorganisms prefer slightly acidic environment. Although resistant against biodeteriorating agents, WWCBs does not emit hazardous chemicals that could pose health hazards during manufacture and in service.

There was no specific test conducted on the thermal insulation and sound absorption of WWCBs manufactured in the Philippines. However, WWCBs have been suggested to have a thermal resistance of 0.18 m2ho/kcal at a board specific gravity and thickness of 0.6 and 15 mm respectively. Thermal resistance increases with a decrease in specific gravity and an increase in thickness (Shigekura, 1989). On the other hand, sound absorption was rated as 0.75 at 4000c/s for boards with a lower specific gravity (de Wit, 1989).

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Applications

The main application of WWCBs in the Philippines is as a construction panel for cost-effective residential houses. It has also been used as flooring, exterior cladding, floors, interior walls, and cabinets. Due to its excellent sound absorption and thermal resistance, it has also been used in theatres and cold storage rooms. Minor applications include uses as signboards, teepees, and roofing taking advantage of its durability and relative water resistance. The main applications and their corresponding thickness is presented in Table 3.

Table 3. Main applications of WWCBs in the Philippines.

 Application

 Board Thickness (mm)
 Ceiling boards

 8
 Exterior wall

 50
 Flooring

 50
 Interior wall

 25
 Kitchen cabinets

 12 to 25

Picture courtesy of Dr. Phil Evans

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Research and Development

Continued research and development is being conducted at FPRDI to improve board properties, manufacturing process and expand the raw material base of the industry. These research projects are financially-funded by local as well as international institutions. A current project on the utilisation of Australian plantation species such as acacias and eucalypts are being collabaratively undertaken by FPRDI, the Department of Forestry of the Australian National University (ANU) and the Division of Forestry and Forest Products of the Commonwealth Scientific and Research Organisation (CSIRO). This project is beingfinancially supported by the Australian Centre for International Agricultural Research (ACIAR).

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References

Bello, E.D. , Commendador, J.B. and A.A. Pablo. 1995. Cement-Bonded Board Industry of the Philippines: A Report to his Excellency President Fidel V. Ramos.

Cabangon, R.J. 1997. Rapid curing of wood wool cement boards from yemane (Gmelina arborea R.Br.) by direct heat application during pressing. Unpublished MS Thesis. University of the Philippines at Los BaÒos, College, Laguna, Philippines.

de Wit, J. 1989. The Elten System. In Moslemi (ed). Fiber and Particleboards Bonded with Inorganic Binders. (Forest Products Research Society)

Eusebio, D.A. and R.J. Cabangon. 1997. Research on Cement-Bonded Composites. Unpublished report. FPRDI, College, Laguna, Philippines.

Kossatz, G., K. Lempfer, and H. Sattler. 1983. Wood-based panels with inorganic binders. Annual Report. Fraunhofer-Institut for Holzforshung, Braunschweig, West Germany. As cited by Moslemi A.A. 1989. Wood-cement panel products: coming of age. In Moslemi (ed). Fiber and Particleboards Bonded with Inorganic Binders. (Forest Products Research Society)

Mallari, V.C., O.R. Pulido, L.A. Novicio and R.J. Cabangon. 1995. Production of cement/inorganic bonded boards for housing construction. Unpublished report. FPRDI, College, Laguna, Philippines.

National Housing Authority (NHA). 1993. Fast Facts on Philippine Housing and Population. NHA, Quezon City, Philippines.

Pablo, A.A., O.R. Pulido, and R.J. Cabangon. 1994. Cement-bonded board technology: Itís development and commercializationí. 1994 DOST Outstanding Commercialization Award. Unpublished report. DOST, Taguig, Metro Manila, Philippines.

Paramasweraan, V.N., F.W. Broker, and M.H. Simatupang. 1977. Microtechnological studies of mineral-bonded wood composites. Interactions between binders and wood. Holzforshung 31(6):173-178.

Shigekura, Y. 1989. Wood fiberboards bonded with inorganic binders in Japan. In Moslemi (ed). Fiber and Particleboards Bonded with Inorganic Binders. (Forest Products Research Society)

Tuazon, B.P. 1999. P21B low-cost housing fund OKd. Manila Bulletin, July 13, 1999. [Online] Available:http://www.mb.com.ph/main/9907/13jm0 [1999, July 13].

Weatherwax R.C. and H. Tarkow. 1964. Effect of wood on setting of Portland cement. Forest Products Journal 14(12):567-570.

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Useful Links

Manufacture of low-cost wood-cement composites in the Philippines using plantation-grown Australian tree species - ACIAR Project FST 95/00

Cement-bonded wood composites

Fine structure of cement-bonded slag wood wool cement board

Manufacturing of excelsior board with latent hydraulic slag cement

 

Acknowledgements

Thanks to: Dr. Phil Evans, Mr. Peter Beutel and Mr. Emmanuel Esguerra.

 

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[ANU Forest Products][Non-Wood Forest Products][Minor and Unusual Forest Products]

Copyright 1999 The Australian National University

Author: Rico Jariel Cabangon

Comment and Feedback

Date last Modified: 27.10.1999

URL: http://www.anu.edu.au/Forestry/wood/nwfp/woodwool/wwcbphil_copy.html