Laminated Strong Eco-Material for Building Contruction Made of Cellulose-Strengthened Wood

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CELLUWOOD is a four years EU project, funded under the Eco Innovation research initiative. The project aims to develop a new range of structural elements made of wood by introducing innovative production elements and includes the use of cellulose instead of petroleum-based glue in the lamination of the timber products. The ‘physical’ results will be the strong eco-beams and columns and their most sustainable manufacturing technologies, in addition to signi�cant environmental and cost bene�ts of the innovation. These are achieved by the introduction of the (new) technologies from other sectors (e.g. cellulose velvet, biocomposite reinforcement and bio-resin) for innovative uses in the defect removal and repairing, facilitating innovation in the use of nano/micro cellulose and bio-resin technologies in timber reengineering, and the development, testing and demonstration of the novel initiative products.

One of the expectations from the project will be to open new market possibilities for laminated wood in construction industry. The clear result of this market's emergence would be a signi�cant reduction in the carbon footprint of construction within the EU and, eventually, worldwide, as the proposed engineered timber became a viable and cost-e�ective substitute for conventional strong construction materials that are high CO2 emitters during manufacture. A further bene�cial result of the new material's emergence would be greatly reduced water consumption in both the manufacturing and construction phases. The proposed technology will also anticipate the massive reduce of the embodied energy in building carcasses, create new opportunities for carbon capture and storage, minimise thermal bridging through insulation layers and improve the possibilities for low-impact recycling of waste materials arising following a building's eventual demolition.

We strongly believe that �nal project results will justi�ed all e�orts that seven project partners have been invested during the project life time.

C E L L U W O O D I N B R I E F

ISSUE at glanceCELLUWOOD in brief

Work in progressand achieved results

Research and Technical Development (RTD) on Structural Timber Boarding

Bio-Resin and reinforcement

Development of Defect Free Lumber

Core Material for Column

Laminated Beam and ColumnModelling

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Development of New Beams andColumns

Impact Assessment and Life Cycle Analysis (LCA)

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After more than two years of the project, the strong commitment of all project partners and intensive experimental work, many important outcomes have been achieved so far and they can be summarised as

W O R K I N P R O G R E S S A N DA C H I E V E D R E S U LT S

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i) Processing technologies of small diameter woodand the main factors which a�ect the quality of �nal wood products have been documented and used for CELLUWOOD development;

(ii) New technologies of nanocellulose and bio-resin have been databased, and nanocellulose reinforced bio adhesives are being developed to maximise the function for CELLUWOOD products;

(iii) Low cost core material for column has been developed;

(iv) The technologies of removing and repairing defects have been successfully developed;

(v) Environmental assessment of CELLUWOOD products has primarily been designed with promising outcomes.

Research and Technical Development (RTD) on Structural Timber Boarding

The main objective of the research activities on Structural Timber Boarding was to obtain detailed information on the utilization of small diameter and underutilized European grown timber, their processes and performance in use on European, national and regional levels from a practical and technical point of view. The task also aimed to de�ne and specify a base composition of the timber resources and timber boarding (lumber) for the future CELLUWOOD materials.

The project team led by InWood and Tecnifusta carried out signi�cant work which results to comprehensive reviews for both, the underutilised wood and lumber boarding processes.

The “assessment of underutilised wood” task has assessed the materials for possible application in CELLUWOOD project at European level.

The “Preliminary processing for lumber boarding” task has evaluated the methods to process the underutilized wood. These included:

the cutting methodologies and geometries of the sawn lumbers,re-engineering processes (e.g. �nger joint) and their strength and weakness the strength, sti�ness, stability and durability of the sawn and boarding lumbers, which are correlated to the parameters and anisotropic behaviour along the longitudinal and across radial and the (joint) parameters and the patterns of the sawn lumbers.

The inputs from structural timber boarding research have served as base for the proposed project innovation.

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The parameters in�uencing and determining the quality of timber boarding materials have been discussed, such as wood species, distribution of wood diameter/size and slope of timber, establishment of correlation of the origin of wood and the property of the underutilized wood to be used in CELLUWOOD project, etc.

Several tree species were under discussion for the use in the project: sweet chestnut (Castanea sativa), Douglas �r (Pseudotsuga menziesii), European larch (Larix decidua Mill), spruce, Norway spruce (Picea abies), Sitka spruce (Picea sitchensis).

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One of the main objectives for CELLUWOOD is to use new technologies (i.e. nano/micro cellulose, bio-resin) to repair, joint and strengthen sawn lumbers to produce strong building components for construction. The overall objective of the work carried on in the scope of bio-resin and reinforcement research has been to integrate the information of the new technologies to maximise their functions for the future CELLUWOOD materials.

There are three main new technologies which were reviewed for use in the project:(i)Cellulose membrane and nanocellulose �brillic paste; (ii)Use of bio-resin;(iii)Use of natural �bre composites.

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Bio-Resin and reinforcement

Regarding the bio-resin, in general, it has been some signi�cant development in last few years, such as a range of renewable and sustainable, formaldehyde-free thermosetting adhesives derived from natural triglyceride vegetable oils (e.g. rapeseed and soya) or phenolic plant oils (e.g. cashew nut shell liquid (CNSL).

The inclusion of bio-resin in building products could have signi�cant environmental, health and safety, and commercial bene�ts.

bio-resin,

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Cellulose membrane and nanocellulose �brillic paste is a product of a novel method for production of natural �bre velvet comprising nano-size �bres or nano�brils which has been developed at Brunel University. The Brunel has fabricated two kinds of nanocellulose reinforced wood adhesives: nanocellulose reinforced epoxy and nanocellulose reinforced casein.

Cellulose membrane and nanocellulose �brillic paste

It has been found that both adhesives can be used in the room temperature under a low pressure and display high performance. By using the nanocellulose reinforced epoxy, the shear strength could be increased by more than 40% when the addition of nanocellulose was 5%. It has been proved that the addition of nanocellulose can also improve the bonding performance.

However, the low water resistance and the shear strain of the natural polymers adhesive are still under investigation.

Lignin glue testing.

The Greek industrial company CHIMAR has been carried out most of the work related to bio resin application in repairing and joins of beams and columns. The CHIMAR team primarily has been focused on developing of cold setting polymers synthesised from renewable raw materials.

The �rst stage in task was conduction of an extensive literature search on such systems, following by numbers of experimental trails with a variety of natural raw materials including lignin, tannin, starch and cashew nut shell liquid.

In parallel, CHIMAR worked on the development of relative adhesives and hardeners based on conventional chemical raw materials.

In 2013 both the bio-based adhesives and the conventional one were sent to partners (Tecnifusta and InWood) for large scale testing in real conditions at their premises. Although the newly developed systems provided some adhesion strength, the �gures were out of the speci�cations determined by the relative European standards.

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Development of Defect Free Lumber

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Currently CHIMAR is working on the optimisation of these systems and new trials will take place early this year.

In addition, the Brunel University team carried out a review of the existing strong natural �bre composites which may be suitable as reinforcement for the production of CELLUWOOD beams and columns.

The use of natural �bre composites was proposed to be used to reinforce the scarf joints of the future CELLUWOOD materials. A nanocellulose gel has been developed and it has been tested with di�erent adhesives to study their bonding properties. These adhesives will be used for the production of the eco-beams and eco-columns.

The further tests are to be continued.

In current production process the timber defects have to be removed of �nger jointed lumber and cross lamination. However, the existing process which suppose the cut out any knot or other defect and discard the wood thus excised, generating signi�cant wastes. The method proposed by CELLUWOOD project will be superior in terms of waste and energy reduction.

Investigation of di�erent defect removals and removing sampling procedures;Repairing with di�erent adhesives;Investigation of scarf joint technologies;

Interim crash test of the products;Comparison with non modi�ed wood.

The major achievements include:

1. Commercial defect removal proceduresdeveloped; 2. Defect repairing kits developed;3. Defect free lumber produced;4. Scar joint technologies investigated;5. Defect free scarf joint lumber produced

Project developed the defect repairing formulations.

Led by Tecnifusta, Spanish engineering company involved in both, traditional carpentry and high-tech wood industrial transformation, the project team so far carried out a signi�cant work related to defeat free lumber including some major activities, such as:

Samples with PUR testing

Defect removal technologies developed by project

Defect free lumber production technologies

Scarf joint lumber production

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Core Material for Column

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Regarding the core material, the objective has been to develop and optimize the concretion core constituents to ensure that the core provides appropriate engineering and durability with due consideration to economic and environmental factors.

The focus has been on the development of new core material which is made of natural �bres and gypsum for the building application.

Four parts of complicated work were carried out with the aim to develop a new light weight in parallel with high mechanical performance of gypsum/natural �bre composite. By compared with three kinds of natural �bres, it was found that sawdust is the best selection. Three chemical agents were used to modify sawdust by using spray coating technology.

Compared with the traditional immerse method, spray coating could improve the modi�cation signi�cantly. Among these agents, Na2SiO3 displayed the highest improvement on the �nal composite. The hemihydrate gypsum binder was modi�ed with systematic experiments which included the extender, retarder, water reducer and reinforce material.

Instron instrument for mechanical testing of gypsum composite

Apart from gypsum, other inorganic bonding materials, such as the expanded perlite and pozolan reinforced with �bre from wood and various agricultural resources like hemp, has been considered as the column in�lling.

In addition to the work proposed in the original project proposal, CHIMAR carried out some developments of the alternatives to PMMA and inorganic bonding materials. Based on these studies it was suggested a novel route for the production of water transporting modi�er. The CHIMAR team also proposed use of the reinforcing hemi-hydrate gypsum paste with nanomaterials and �bres from agricultural residues as alternative solution to the use of water transporting modi�er.

Gypsum/sawdust composite (a) with Na2SiO3 spray coating and (b) without Na2SiO3 spray coating

Comparison of Na2SiO3 modi�ed sawdust with various process on the mechanical performance of gypsum composite

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Laminated Beam and Column Modelling

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In order to predict the behaviour of CELLUWOOD product (Eco-beam and columns), appropriate mathematical and computer models have been derived. These complex beam models were developed by CBD (Slovenian based construction design company). CBD applied classical mechanical behaviour and �nite element theories combined with the knowledge of speci�c anisotropic timber properties to guide the CELLUWOOD beam and column development process as well as to enable the prediction of the components’ performance. The performance of the components was assessed in order to obtain the resulting properties (damage) of the elements.

Major work has been carried out in the �rst half of the project including: 1) modelling beams and columns from the end user’s requirements; 2) establishing the correlation between the resulting properties, the raw materials and the processing parameters; 3) �exural, compression, and buckling behaviour of columns and beams; 4) fracture mechanisms – main material or glue lines; 5) model development and adjustment to experimental results.

CBD developed various mathematical models for new CELLUWOOD beams and columns. It considered various assumptions and performed a vast parametric study with di�erent boundary conditions. The complex �nite element models for beams and columns have been developed by using shell and solid �nite elements. The models have also been compared with frame �nite elements.

More importantly, CBD has developed simpli�ed procedures, namely taking the basic mechanical theories and upgraded them with speci�c details suitable for the new CELLUWOOD elements. These procedures are most appropriate for code implementation. They already use certain parts of the Eurocode 5 standard (design standard for timber structures in Europe) and allow for instant implementation of newly developed elements into regular building practice.

Nevertheless all the mathematical models will have to be supported by experimental testing to further con�rm the computer results.

A beam example – beam 3D render (top), 3D �nite element model (middle) and shear stress �eld (bottom)

Column �nite element model - shell and solid FE used

An example of models developed

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Development of New Beams and Columns

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The development of new beams and columns is going to be based on modelling results. So far some preparatory works have been performed. The repaired and scarf jointed lumber is to be used to develop the novel construction products, which will be low carbon, sustainable, viable, low cost and with good environmental pro�les. There are several objectives which are going to be taken in consideration in the process of the development of the new Eco beams and columns, such as follows:

Design and assembly of lumber layers in accordance with the modelling results and the grading of the repaired lumbers based on the statistics of work package “Development of defect free lumber”;Development of new processes and technologies for manufacturing beam and columns by using the new lumber materials developed;Interim assessment of the novel composites developed; Optimization of the processes to ensure the development of the strong CELLUWOOD materials with e�cient uses of raw materials and other resources.

An example of new CELLUWOOD beams: lamination and test

Impact Assessment and Life Cycle Analysis (LCA)

The environmental evaluation of CELLUWOOD project is to verify the decisive environmental and economic aspects associated with the knowledge on new materials deriving from the project compared with the traditional ones.

Eco-e�ciency describes how environmental friendly and economical a product or process is. Through determination of the total impact on the environment and all costs from manufacture to disposal the complete value-added chain is covered. The eco-e�ciency aims to achieve a balance between environmental and economic factors. This means to manufacture cost-e�ective products with the smallest possible amount of raw materials and energy, and to minimize emissions.

The analysis of the environmental term includes a life cycle assessment of the new CELLUWOOD materials developed in the project, versus the traditional glulam manufacturing process.

Regarding wood as the main raw material, forestry products have been studied. The whole forest exploitation environmental impact is allocated between the several forest products obtained (classi�ed according to their quality) on base of an economic criteria, which is the real cause of forest processes. Also, the traditional glulam manufacturing process have been analysed by performing a cradle to gate Life Cycle Assessment (LCA), and by using two di�erent environmental evaluation methodologies: a mid point methodology (CML 2000) and a �nal point methodology (Ecoindicator 99).

Source. www.naturallywood.com

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The �rst one shows results by individual environmental impact categories; meanwhile the second one allows an additional “weighting step” to obtain a unique adimensional value to represent the global environmental impact. Obtained results by using both methodologies show that high quality wooden material (classi�ed as C24) generates the main environmental impact of the glulam element manufacture (about the 74% according to Ecoindicator 99 results). The second signi�cant aspect is the consumption of the other raw material - the adhesive (near the 20% according to Ecoindicator 99 results).The expected CELLUWOOD results improving the operation of knot and check repairing with nanocellulose adhesive will allow using smaller diameter logs (classi�ed with lower quality degree and lower price) in the process.

PROJECT CONSORTIUM

Glulam manufacturing process in TECNIFUSTA: results (Ecoindicator 99 methodology)

In consequence, the �nal environmental impact associated to the consumption of wood will decrease. By the other side, as smaller logs have lower price, eco-e�ciency factor will be double improved.

Also natural reinforces and bioresin are expected to reduce the environmental impact due to the adhesive traditionally employed, which used to be based on non removable resources.

In consequence, the success of the project can improve decisively the environmental impact of the �nal product, and also its eco-e�ciency.

AIDIMA, a Technological Institute located in Valencia (Spain), with an extensive experience in wood sector research and development projects has been the leading project partner for the Life Cycle Analysis (LCA) and environmental evolution task.

InWood Developments Ltd (UK)Tecnifusta Enginyeria SL (Spain)Contemporary Building Design CBD d.o.o (Slovenia)Chimar Hellas S.A. (Greece)Research and Development Association for the Wood, Furniture and Packaging industries AIDIMA (Spain)Brunel University (UK)InnovaWood asbl (Belgium)

CONTACT

Mr. Edward StenhouseProject Coordinatoredwardstenhouse@btconnect.com

Prof. Dr. Mizi FanProject ManagementMizi.Fan@brunel.ac.uk

InnovaWoodProject Web and Disseminationo�ce@innovawood.com

"This publication has been produced with the assistance of the European Union. The contents of this publication are the sole responsibility of project consortium and can in no way be taken to re�ect the views of the European Union”

Miguel Ángel AbiánProject Coordinator and Management at AIDIMAcomercial@aidima.es