Routine inspection of wood utility poles to detect internal decay involves drilling holes at or about the ground line. While these holes are useful for detecting internal decay, their presence raises concern among engineers about their potential effects on pole flexural properties. The effect of inspection holes on flexural properties...
The effect of copper naphthenate treatment on electrical resistance of Douglas-fir utility poles was compared with similar
poles either left untreated or treated with pentachlorophenol (penta). Penta-treated and untreated wood had similar electrical
resistance shortly after treatment and after a 3-month outdoor weathering period. Electrical resistance of copper naphthenate–
treated...
The goal of this study was to develop an understanding of the nature of wave loading on a wood-framed scale residential building model for a variety of building configurations and test conditions. Testing was performed on a 1/6th scale two-story wood-framed residential structure. The structure was impacted with waves and...
The performance of full-scale light-frame wood walls subjected to wave loading was examined using the Large Wave Flume of the Network for Earthquake Engineering (NEES) Tsunami Facility at Oregon State University. The hydrodynamic conditions (water level and bore speed) and structural response (horizontal force, pressure, and deflection) were observed for...
The performance of full-scale light-frame wood walls subjected to wave loading was examined using the Large Wave Flume of the Network for Earthquake Engineering (NEES) Tsunami Facility at Oregon State University. The hydrodynamic conditions (water level and bore speed) and structural response (horizontal force, pressure, and deflection) were observed for...
Instrumentation for rapid, high precision size analysis of silt and sand size particles has been acquired and/or developed by the marine geology group of the School of Oceanography of Oregon State University. A Cahn automatic electrobalance with particle sedimentation accessories is used for size analysis of the silt fraction of...
Earthquake tests have trouble imitating the randomness and varied nature of actual earthquakes. Scientists seek to remedy this and make buildings safer by creating dynamic tests that imitate the random nature of earthquakes. Featuring Dr. Rakesh Gupta.
The effect of grain angle (GA) on shear strength of Douglas-fir has been evaluated. Shear block specimens with a GA varying from 0 to 90° was loaded in the shear plane, resulting in failure mode transitioning from parallel to grain shear to rolling shear. As expected, shear strength decreased as...
The effect of grain angle (GA) on shear strength of Douglas-fir has been evaluated. Shear block specimens with a GA varying from 0 to 90° was loaded in the shear plane, resulting in failure mode transitioning from parallel to grain shear to rolling shear. As expected, shear strength decreased as...
In a homogenous and isotropic material, the location of the neutral axis coincides with the location of the centroid of the beam. Wood is anisotropic, meaning that it has different properties in different directions. It is also non-homogenous, meaning that the beam exhibits different properties at different locations throughout its...
This paper presents the results of a test program whose goal was to better understand the contribution of individual elements to the performance of typical light-frame wood structures during tsunami loading. The intent was to be able to replicate failures in a structural engineering laboratory that were observed during laboratory...
Tsunami force and pressure distributions on a rigid
wall fronted by a small seawall were determined experimentally
in a large-scale wave flume. Six different
seawall heights were examined, two of which were exposed
to a range of solitary wave heights. The same
experiment was done without a seawall for comparison....
It is commonly accepted that for the analysis of wood beams, the neutral axis coincides with the centroid of the beam. Although this assumption is used in analysis, wood is not an isotropic material, as it has different elastic properties in the tangential, radial and longitudinal directions, nor is it...
Since 2004 there have been multiple devastating tsunamis around the globe triggered by large magnitude earthquakes; with the most recent being the Tohoku, Japan tsunami in March 2011. These tsunamis have caused significant loss of life and damage to the coastal communities impacted by these powerful waves. The resulting devastation...
For wood beams, it is often assumed that the neutral axis is located at the centroid of the
beam. The neutral axis of isotropic, homogeneous materials is located at the centroid of the
material, but wood is neither isotropic nor homogeneous. The varying grain patterns and
knots located throughout wood...
The forces exerted on light-frame wood buildings as a result of surge and waves are not fully understood. With a better understanding of these types of forces, it may eventually be possible to build coastal structures to better withstand the loads. In this paper, a recent two part experimental study...
It is commonly accepted in the analysis of wood beams that the neutral axis coincides with the beam's centroid. However, wood is not an isotropic material, has different elastic properties in the tangential, radial and longitudinal directions, and is non-homogeneous, as it contains characteristics such as knots. Therefore, there is...
Wood shear walls are the main lateral force-resisting system for wood-frame construction. Water intrusion and subsequent decay around connections can significantly impact shear wall behavior, but these problems are seldom studied. In this study, effects of water intrusion and fungal attack on shear wall capacity were examined using small-scale (610-...
ASTM standard sizes for bending tests (either 50 × 50 mm or 25 × 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the...
This thesis is comprised of two manuscripts based on a laboratory experiment conducted to examine realistic wave forcing on a vertical wall subjected to tsunami loading. The first manuscript examined tsunami force and pressure distributions on a rigid wall that was fronted by a small seawall. Six different seawall heights...
There are over 130 million wood poles supporting electrical transmission and distribution lines in the U.S. The vast majority of these poles are preservative treated to prolong their useful life. In some cases, however, the depth of treatment is relatively shallow, leaving a deep zone of moderately durable, untreated heartwood....
Cob, similar to adobe, is an earthen building material made of soil, sand, and straw. Although cob was used to build homes in England centuries ago, it has reemerged as a sustainable and relatively inexpensive, alternative building material. A possible solution for housing in impoverished nations, cob needs to be...
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amazingly supportive and
patient thesis committee.
MiloClauson, for facilitating the use of his lab
Residential energy use is a significant contributor to greenhouse gas emissions and climate change. Reducing energy efficiency in conventional wood-framed houses are thermal bridges: direct paths that allow heat to flow through the studs instead of the insulation. One suggestion for reducing thermal bridging is the staggered stud (SS) wall....
The objectives of this study were to evaluate the performance of wood-frame shear walls under monotonic and cyclic loads by: 1) determining variability of shear wall performance; 2) comparing performance of walls under each loading protocol; 3) evaluating effects of anchorage on wall performance; and 4) evaluating performance of walls...
Over the last half-century, scientists and engineers have developed methods to better understand and mitigate the damage caused by tsunamis. According to U.S. Federal Emergency Management Agency (FEMA) P646, buildings in many regions including the U.S. Pacific Northwest, will experience substantial ground shaking from an offshore earthquake that precedes a...
An experiment in 199 m of water on the Oregon shelf produced continuous current speed profiles
down to the sediment-water interface. These profiles show that the velocity structure above the
viscous sublayer is consistent with that expected when form drag influences the boundary layer flow.
They show two logarithmic-profile regions,...
The Cocos Gap is a deeper portion, or saddle, of the Cocos
Ridge and forms part of the western boundary of the Panama Basing
It is probably typical of saddles within most submarine ridges, In
order to determine the mechanisms controlling sediment dispersal,
the nature and sources of the sediments...
The development of cross-laminated timber (CLT) panel technology has opened up new opportunities for wood in tall buildings. Several characteristics including seismic performance and speed of construction have raised interest among designers. As CLT gains acceptance in the industry, alternative structural solutions need to be investigated to improve performance of...
This thesis is comprised of a manuscript based on a laboratory experiment run in the Tsunami Wave Basin as part of a research project funded by the Network for Earthquake Engineering Simulation called Housesmash. The purpose of the experiment was to better understand the role of the urban environment, represented...
Over the last decade the world has seen three major tsunamis strike the coasts of
Indonesia, Samoa, and Chile. These tsunamis have caused significant losses of life and
property on the coastal cities of these and nearby countries. The NEES (Network for
Earthquake Engineering Simulation) Housesmash project was created to...
Bedrock groundwater dynamics in headwater catchments are poorly understood and
poorly characterized. Direct hydrometric measurements have been limited due to the
logistical challenges associated with drilling through hard rock in steep, remote and
often roadless terrain. Here we develop and use an inexpensive, portable bedrock
drilling system to explore bedrock...
This study investigated the effect of exposure to elevated temperature on the yield strength of single-shear nail connections when subjected to lateral loading. Solid sawn lumber and laminated veneer lumber were used as framing members and two different thicknesses of both oriented strand board and plywood were used as the...
The overall goal of this project was to design a wood frame shear wall that could withstand greater displacement before damage occurred to the gypsum wall board (GWB). A total of 14 shear walls consisting of seven different designs with two walls built per design were tested to failure. Six...
Earthquake performance of wood-frame shear walls was evaluated by comparing fully and partially anchored walls under monotonic, cyclic, and earthquake loads and comparing with code measures. Suitability of monotonic and cyclic testing to predict seismic performance was examined. Earthquake tests were conducted on 2440-mm-square walls with Douglas-fir studs. Two oriented...
The purpose of this thesis was to evaluate orthogonal cutting as a method to determine the fracture toughness of low and high density polyethylene and wood plastic composites. A test fixture was developed to capture normal and tangential cutting forces at variable depth and rake angle. A tool interface method...
The goal of this study was to optimize a through-boring pattern that will provide adequate preservative penetration while minimizing the reduction in overall pole bending strength. Hole spacing was developed using longitudinal and transverse chemical penetration data from previous studies. Finite element analysis was used as a preliminary assessment tool...
Timber engineering is currently in the midst of a significant evolution due to the rise of mass timber products, like cross-laminated timber (CLT). Increasing numbers of structural engineers are facing the challenge of designing lateral-force-resisting systems (LFRS) for multistory CLT structures. LFRS solutions such as steel frames, concrete cores, or...
Heavy timber framing relies primarily on bracing to withstand lateral loads due to earthquakes and wind events. Bracing configurations in heavy timber framed buildings vary widely and include cross bracing, knee bracing, and other geometries. Many heavy timber frames constructed during colonial American times are still standing, exceeding the expected...
Sandwich composites are typically produced from two high strength facings bonded to a lower strength, lightweight core. Sandwich design has proven to be efficient for applications demanding high strength and low weight. Wood-based sandwich composites have been largely limited to non-structural applications with the exception of structural insulated panels and...
Focus on Forestry is published by Oregon State University's College of Forestry. Our goal is to keep Forestry alumni, friends, faculty, staff, and students informed about the College of Forestry and its many activities and programs.
Accelerated weathering (AW) tests have become a requirement for many wood composite products. This project monitored temperature and moisture content of specimens undergoing AW exposure for the following standards: ASTM D3434 (automatic boil test), CSA O112.9 (boil-dry-freeze), and PS2 (Section 7.17, 6-cycle VPS). Each AW procedure was conducted with three...
Sodium-ion batteries (SIBs) require the use of a highly reversible anode. To form this anode carbon nanofibers and nanocrystals are derived from cellulose nanofibers, cellulose nanocrystals, and bacterial nanocellulose. The primary structure of the cellulose nanofibers is maintained when carbonized allowing for high surface area in the structure. The carbon...
One of the recent additions to the panoply of engineered wood products is cross-laminated timber (CLT). CLT is a prefabricated, large-scale, solid wood panel that consists of multiple layers of lumbers stacked together, with each layer arranged perpendicular to the next layer, glued with structural grade adhesives, and pressed. The...
• Reduced lignin content in perennial crops has been sought as a means to
improve biomass processability for paper and biofuels production, but it is unclear
how this could affect wood properties and tree form.
• Here, we studied a nontransgenic control and 14 transgenic events containing
an antisense 4-coumarate:coenzyme...
This study examined the relationship of interfacial shear strength (IFSS) and
bending strength (MOR) of several different wood-plastic composites (WPC's).
Plastics utilized were high-density polyethylene (HDPE) and polypropylene (PP).
Pine and oak were used as the wood species. Compatibilizers used included maleicanhydride
polyethylene (MAPE), polymeric methylene diphenyl diisocyanate (PMDI),
KymeneTM,...
Epoxy resin is a thermosetting resin that is commonly used as composite matrix. Epoxy composite materials are well utilized in industries, such as aerospace, due to their good mechanical properties. Nano-scale filler reinforced polymer composite materials have been intensively researched in recent decades. Cellulose nanocrystals (CNXLs) are a type of...
New species introductions have been associated with the movement of
people for thousands of years. For instance, horses were introduced into North
America by Spanish explorers, while pigs were introduced by the Polynesians
into many Pacific islands long before the establishment of permanent
European settlements. Both of these species introductions...
Focus on Forestry is published by Oregon State University's College of Forestry. Our goal is to keep Forestry alumni, friends, faculty, staff, and students informed about the College of Forestry and its many activities and programs.
Focus on Forestry is published by Oregon State University College of Forestry. Our goal is to keep Forestry alumni, friends, faculty, staff, and students informed about the College of Forestry and its many activities and programs.
Post-tensioned (PT) self-centering shear walls were designed to reduce structural damage from seismic activity. However, these lateral force resistant systems experience post-tension loss negatively affecting the re-centering capability due to delayed deformations experienced by engineered wood products over time. The long-term mechanical response of mass-timber panels to in-plane PT loads...
The United States generates over 70 million tonnes of wood waste annually, with over 27 million tonnes still available for recovery. Current recycling rates for wood waste are in the range of 10% to 15%, which is much lower than other common building materials and indicative of an underutilized resource....
The context of this thesis is a research project focused on the investigation of a renewable biopolymer-poly(lactic acid) (PLA) as a potential replacement of petroleum-based polymers in advanced nanocomposites reinforced with Microfibrillated cellulose (MFC). MFC is extracted from wood, which is a renewable, sustainable, carbon neutral and recyclable material. This...
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valuable advice and help. I would
also like to acknowledge MiloClauson for his guidance and help with
The finite element software framework, OpenSees, has been used by researchers
to simulate the response of structural and geotechnical systems to earthquake loading. Implementation of the Particle Finite Element Method (PFEM) has made it possible to simulate hydrodynamic forces through fluid-structure interaction (FSI) in OpenSees. To validate the FSI implementation...
Polylactic acid (PLA), a renewable material, is used widely in a variety of commercial and specialty applications. However, certain limitations such as high temperature stability and brittleness limit its applicability. This problem is addressed by reinforcing PLA with a variety of materials but the process gives rise to different issues...
Many nondestructive techniques for structural health monitoring are subjective and based on visual observations of degradation. In addition, dynamic properties of structures are already used to obtain quantitative structural health data. However, most current data collection is limited to localized damage on the structure, rather than global response. Recent research...
Literature reports have indicated that application of
sonic pressure waves enhances the rate of impregnation of
preservatives in wood. However, these studies have been
limited and inconclusive. The technique or process is not
in commercial use. In this study a laboratory scale
treating cylinder connected to a mechanical sonic wave...
Increased competition in the market place for both occasional and professional chain saw users has led to a desire for improved performance in chain saw guide bars. One aspect of improved performance is lower bar weight. The primary focus of this research was to establish the feasibility of a lower...
Holocene bulk sediment and component accumulation rates were
measured in twenty-eight piston and gravity cores taken from the
floor of the western Panama Basin and on the surrounding ridges.
Radiocarbon ages and oxygen isotope curves provided Holocene age
control in nine cores. Time datums in nineteen other cores were
inferred...
Detailed current profiles between the sediment-water interface
and 20 cm above it reveal a viscous sublayer in the bottom boundary
layer on the Oregon continental shelf. Data from three field experiments
are used to test fundamental assumptions about boundary layer
flow in the ocean. The first study, discussed in Chapter...
Wood adhesives are essential components of wood composites. At
present, the commonly used wood adhesives, phenol-formaldehyde (PF)
and urea-formaldehyde (UF) resins, are petroleum-based synthetic resins
that may result in emission of formaldehyde in the production and use of
wood composites. Because the world's oil reserves are naturally limited
and formaldehyde...
The objectives of this study are: (1) to evaluate the effect of reference
displacement on wall behavior under fully reversed cyclic loading using the
CUREE test protocol and (2) to assess damage accumulation (visible fastener
damage and stiffness degradation) for the imposed drift levels. All tests were
conducted on identical...
The objective of this study was to determine the effect of misplaced hold-downs
on the static and cyclic behavior of wood shear walls. Three shear wall
configurations were considered in this study. The first configuration (control) had
hold-downs at the ends of the wall (wall type 1), the second configuration...
The advantages of high-temperature drying are faster drying, reduced inventory, reduced energy requirements, and reduced equilibrium moisture content. However the disadvantages are higher initial costs of the kiln, greater power needs, knot dropout, and reduction in some strength properties. The latter was the subject of this study. Three hundred pieces...
Wood stiffness is one of the most important properties of lumber and veneer. We studied wood stiffness (modulus of elasticity, MOE), wood density, microfibril angle, and knots in a 25 year-old wind pollinated progeny test (50 families, ~ 373 trees) of coastal Douglas-fir to understand the potential for genetically improving...
The overall goal of this study was to evaluate an alternative to
traditional wood framed shear wall construction. This study introduced the
innovative idea of using a water and seismic damage resistant, wood-concrete-
composite (WCC) construction instead of an all-wood design. The
WCC design consisted of a thin shell of...
Delayed tree mortality is an unpredictable occurrence when prescribed burning is implemented. Fire scorched trees may die as the result of crown scorching, stem charring, root injury, bark beetle attack, or through a combination of these factors. This study examined ponderosa pine mortality and the incidence of two bark beetle...
The overall goal of this study was to gain an insight into the load sharing aspect between oriented strand board (OSB) and gypsum wall board (GWB) in shear wall assembly during racking load. More specifically the objectives of the study were to: (1) evaluate qualitatively the load sharing between OSB...
The majority of low-rise residential structures in the U.S. are constructed with wood. Wood-based composites are primary building materials in these structures, used as structural sheathing, joists, and beam components. Wood composites are susceptible to degradation upon exposure to high levels of moisture. Moisture durability is routinely assessed with accelerated...
Engineers, in practice, are often faced with the challenge of evaluating a fire-damaged structure and developing a rehabilitation and retrofit plan. In order to decide on a rehabilitation and retrofit plan, information on thermal degradation of building materials and connections are vital. A critical knowledge gap exists in terms of...
Focus on Forestry is published by Oregon State University College of Forestry. Our goal is to keep Forestry alumni, friends, faculty, staff, and students informed about the College of Forestry and its many activities and programs.
This thesis consists of three manuscripts related to the methodology of evaluating charring behavior in cross laminated lumber panel specimens subjected to fire performance tests on cross-laminated lumber panel specimens. The topic of the first manuscript is the measurement of char rates of unprotected CLT layups fabricated with ponderosa pine...
Wood plays a key role in modern electrical infrastructure; crossarms and power poles utilize the high strength to weight ratio, availability and low cost of wood to facilitate the access of power to millions of Americans. However, wood presents a variety of challenges as a material. In structural applications, one...
Parcellization of the rural landscape threatens the provision of social, ecological and economic benefits to society due to loss of economies of scale. A continued provision requires new approaches to forest management for multiple, interconnected goals. I used interviews, archival records and field measurements to learn how select, experienced owners...
The goal of this project is to contribute to the development of design values for cross-laminated timber (CLT) diaphragms in the seismic load-resisting system for buildings. Monotonic and cyclic tests to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with common self-tapping screws were performed....
Many wood composites are known to poorly resist the effects of moisture and temperature extremes over time. Degradation of adhesive bonds, irreversible thickness swell and dimensional instability result in a decrease of properties and a possible failure of the material. Accelerated weathering has become an essential tool for assessment of...
Engineered wood composites are used in many structural applications and are intended for dry use. However, these materials may encounter significant amounts of wetting while in service, which can lead to structural failures. This study combined aspects of wood science, mechanics, structural engineering, and mycology to assess changes in material...
Controlling the orientation and spatial distribution of
discontinuous fibers in composite materials enables product
properties to be tailored to anticipated use. Electric
fields are already (albeit rarely) used to affect alignment
in lignocellulosic (LC) fiber composites. The use of
magnetic fields has not, however, been suggested or
explored; this is...
The objective of this project was to evaluate methods to remediate a wood I-joist with a single, circular hole in the web while leaving utilities in place. The methods were experimentally evaluated with a full-scale bending test using four equally spaced point loads. There were three depths of joists with...
Wood and wood-based composites are being used in either
new or more demanding applications. A means is needed to
successfully analyze new materials and to predict their long-term
performance. Two techniques, dynamic mechanical
analysis (DMA) and time-temperature superposition (TTS) offer
a means to accomplish this objective. The outcome of this...
Formaldehyde-based adhesives such as urea-formaldehyde (UF), phenol-formaldehyde (PF) are widely applied in wood-based composite industry. However, these adhesives are all petrochemical-based and could not sustain in a long term due to a limited reserve of oil and natural gas. Moreover, these adhesives emit carcinogenic formaldehyde in the production or use...
The overall goal of this project was to design a wood frame shear wall that could withstand greater displacement before damage occurred to the Gypsum Wall Board (GWB). More specifically, the objectives of the study were: (1) to evaluate damage to the GWB in alternative shear wall designs at 1%,...
The goal of this study was to develop an understanding of the nature of surge wave loading on
wood framed residential structures for a variety of building configurations and test conditions.
The objectives of the study were: (1) to measure forces on a 1/6th scale wood framed
residential structure, (2)...
While the heartwood of many wood species exhibits excellent resistance to fungal and insect attack, this resistance is sometimes diminished in second-growth material of the same species. The reasons for the reduced durability are unclear, but they may reflect a combination of both higher proportions of sapwood as well as...
A mathematical and then a numerical model were developed for simulating a convective batch lumber drying process. The model incorporates mass and heat transfer relationships within the lumber stack, as well as thermodynamic properties of the wood and drying air. It takes into account a change of air properties along...
The objective of this research project was to increase the density, strength, and stiffness of two low to medium-density diffuse-porous hardwood species. Wood used in this study was processed using a method of wood densification known as “Viscoelastic Thermal Compression” (VTC). The VTC process is a three phase treatment which...
With growing interest in mass timber, especially mass timber panels (MTP), there has been a need to better understand their structural properties. One of the most versatile uses for MTP are as floor systems. Under new code provisions, these floors can be utilized in new and taller building types, but...
Restoration programs effectively prevent or mitigate wildfires and pest outbreaks in the forest lands. The most common approach is to selectively harvest smaller and dead trees in order to preserve larger and superior trees. Ponderosa pine, Pinus ponderosa, (PP) lumber is one of the common species harvested from restoration programs...
Cross-laminated timber (CLT) is revolutionizing the use of wood in the construction sector of North America as a solution for walls and diaphragms in mid-rise or even high-rise timber structures on account of its environmental advantages, high strength-to-weight ratio, fire-safety performance, and propensity for prefabrication. However, considering the hygroscopic nature...
Dimensional stability of wood-based composites with changing moisture content remains an important challenge in the industry for many applications. Wood modification technologies have shown significant improvement in dimensional stability by altering the chemistry of the wood substrate, or by filling the available space in the wood microstructure that otherwise would...
As mass-timber building construction rises around the globe, there exists the need to verify the long-term, in-situ behavior and performance of these structural systems. Structural health monitoring (SHM), generally defined as a damage detection strategy consisting of a network of sensors, a data acquisition system, and algorithms for data analysis,...
Wood-based composites such as plywood and particleboard are produced with a thermoset adhesive via a hot-press process. At present, UF is the most commonly used thermoset adhesive for production of decorative plywood. The emission of the carcinogenic formaldehyde from UF-bonded panels during the use of panels affects the indoor air...
Wood composites are an important renewable structural material which can be a net carbon sink when used in combination with sustainable forest management practices and high rates of log utilization. Adhesive bondlines are an essential part of composites, and for wood composites, they determine the moisture durability and mechanical performance...
Each year the United States: Forest Service (USFS) spends billions of dollars fighting forest fires. One strategy used by the USFS to prevent catastrophic fires is through forest restoration programs, in which potential forest fuel is removed through mechanized thinning. This program is expensive and generates high volumes of small-diameter...
In wood-based composites, the glue-line (interface) between wood-strands affects the stress transfer from one member to the next. The glue-line properties determine the rate of load transfer between phases and these properties depend on wood species, surface preparation, glue properties, glue penetration into wood cells, and moisture content of the...
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many people at OSU, my colleagues for their help and
companionship during my stay at OSU, Mr. Milo
Western juniper (Juniperus occidentalis) is a conifer that is native to Oregon, California, Washington, Nevada, and Idaho. Juniper is known to have highly decay resistant heartwood and is a popular choice for finished furniture. With recent forest management practices over the past 100 years have resulted in an immense population...
Moisture durability is essential for wood composites, especially those used in building construction, where products are prone to weathering. The primary focus of this research was to determine if adhesive penetration into the cell wall has a positive influence on adhesive bond durability. To fully understand the measureable effects of...