Long-term assessment of chestnut live cribwalls deterioration using drilling resistance measurements

An IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the impact of white and brown rot decay on drilling resistance (DR) measurements in wood. In total, 720 drillings were made in specimens of Scots pine (Pinus sylvestrisL.) heartwood and sapwood, European beech (Fagus sylvaticaL.) and English oak (Quercus roburL.), which were decayed byConiophora puteanaandTrametes versicolor. Drillings were made with specimens conditioned in normal climate (20°C/65% RH) and with specimens vacuum-impregnated in water. DR and feeding force (FF) were negatively correlated with mass loss (ML) due to fungal decay. The intensity of reduction was higher for DR than for FF with increasing ML for all decay types and moisture contents (MCs). A significant difference (at 95% confidence level) in DR was found between decay types using water-saturated (WS) Scots pine specimens (3–35% ML). In most cases, DR revealed a higher predictive power of the models for ML prediction than FF. Free water in decayed specimens significantly reduced the DR and FF. Hence, the effect of ML on DR and FF of decayed and WS wood was less prominent.

Drilling resistance (DR) measurements is widely used for nondestructive testing and evaluation of wood in growing trees and timber structures. A DR method can be applied in the regions with a cold climate and in wood with temperatures below zero degrees Celsius and varied moisture content (MC), which raises a question of correct interpretation of DR profiles and prediction of wood properties. Laboratory tests were conducted on Scots pine specimens with four levels of MC (7.4%, 11.0%, 23.5%, 147.9%) and temperature (+20°С, +2°С, −2°С, −10°С) variations. In-field tests were made on 33 growing trees at +18°С and −15°С. An IML-RESI PD 400 tool with a fixed rotational frequency of 2500 rpm and a feed rate of 1.5 m·min−1 was used. In most cases, wood temperature and MC had a significant influence on DR, but differences in an absolute value could be slight. A drastic increase in DR and feeding resistance was observed for water-saturated specimens tested at −10°C. For structural health assessment of timber structures at temperatures below 0°C, it is recommended to control wood MС. The effect of MC on DR was pronounced for groups of specimens with temperatures below and above the fibre saturation point. The in-field tests confirmed an increase in DR for frozen wood that can be used for studying water-conducting layers in growing trees.

ABSTRACTIML-Resi PD-400 drilling tools (IML System GmbH, Wiesloch, Germany) were used to study the influence of the feed rate and the rotational frequency of the drill bit on the drilling resistance (DR) measurements. The study presents theoretical aspects concerning chip formation, kinematics (speeds, cutting angles, chip thickness) and cutting forces distribution during the drilling process. Drill bit rotational frequency and feed rate have an impact on nominal chip thickness or a feed rate per major cutting edge of the drill bit, and were correlated to DR measurements. Varied rotational frequency and feed rate had a significant impact on DR and feeding resistance (FR). Positive correlations between feed rate per major cutting edge and DR (FR) for the individually tested wood species can be described by allometric functions (R2 = 0.93–0.99). Wood density had a partial impact on correlations between feed rate per major cutting edge and DR (FR).

An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to study the influence of the drilling direction in relation to wood grain orientation on drilling resistance (DR) and feeding resistance (FR) measurements. The drilling tests were performed on Scots pine, European beech, English oak and Silver poplar conditioned in a standard climate. The differences in DR between radial and tangential drilling direction were negligibly small or minor for both drill bit types. In contrast, the difference between longitudinal and tangential drilling direction was more pronounced but differed between wood species and drill bit types. FR was the most sensitive parameter to changes in the wood grain orientation when using a drill bit with a single major cutting edge. The mean FR decreased by approximately 27% for Scots pine, 33% for Beech, 37% for Oak and 40% for Poplar when changing the drilling direction from longitudinal to tangential. It was concluded that the drilling direction between longitudinal and transversal drillings needs to be considered for the prediction of wood properties based on DR measurements. Potential applications of drill bits with a single major cutting edge can be the object of further studies.

Drilling resistance measurement (DRM) is recognised as an important on-site micro-invasive procedure for assessment of construction materials. This paper presents a detailed investigation of user-controlled variables and their influence on drilling resistance. The study proves that the ratio of penetration rate/rotational speed is proportional to drilling resistance. Data from Bath stone and an artificial reference stone demonstrates how different materials can be compared using their intrinsic specific energy. It is also shown that adjusting drilling settings does not significantly change drilling measurement variability. However, settings producing high drilling resistance can significantly contribute to drill bit wear. A theoretical framework in which tests can be optimised without compromising the ability to compare data is presented. The framework is of high significance to the conservation industry and will promote a more effective use of DRM. DRM is a minimally invasive procedure particularly appropriate for sensitive heritage structures. Its use can provide the essential mechanical property data required for evaluation of surface consolidation products and specification of repair materials.

An IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the combined effect of wood moisture content (MC), drill bit rotational speed and feed rate on drilling resistance (DR) and feeding force (FF). Tests were made with Norway spruce (Picea abies (L.) Karst.) conditioned in a normal climate (20°C/65% RH), at 20°C/95% RH, vacuum-pressure impregnated in water, and oven-dried. Rotational speeds and feed rates had an impact on feed rate per cutting edge for the major cutting edge of the drill bit which was used for correlation with DR and FF for various MC. Impact of MC on DR and FF depended on rotational speeds and feed rates of the drill bit. For feed rates per cutting edge less than 0.09 mm, DR was higher for water saturated (WS) specimens. Negligible differences between DR for various MC were found for feed rates per cutting edge between 0.09 and 0.15 mm. DR was higher at low MC for feed rates per cutting edge which were higher than 0.15 mm. FF extremely increased in conditioned (20°C/95% RH) and WS specimens at feed rates per cutting edge less than 0.1 mm.

An IML-RESI PD 400 drilling tool and a standard spade drill bit were used to find the correlations of drilling and feeding resistance with the modulus of elasticity in static bending and density of wood. In total, 1575 drillings at 0.5, 1.0 and 1.5 m/min feed rates were made in specimens of Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.), English oak (Quercus robur L.) and common lime (Tilia europaea L.), which were oven-dried, conditioned at 20 °C/65% RH and 20 °C/95% RH and vacuum-impregnated with water. The feed rate (feed rate per major cutting edge or uncut chip thickness) had a significant impact on the prediction of density and modulus of elasticity through drilling resistance measurements and should be considered for comparison of properties and internal conditions of wood. Because of stronger correlation between drilling resistance and tested wood properties compared to feeding resistance, drilling resistance is recommended for density and MOE prediction of sound wood. Moisture content had no significant impact on the modulus of elasticity prediction by the drilling resistance measurements, while density can be predicted by linear models for two stages of moisture content variation, below and above fibre saturation.

Мобильное устройство для измерения сопротивления сверлению IML RESI PD-400 и стандартное тонкое буровое сверло (IML System GmbH, Вислох, Германия) использовались для установления взаимосвязи сопротивления древесины сверлению и подаче с плотностью, модулем упругости и пределом прочности бездефектной древесины сосны (Pinus sylvestris L.), бука (Fagus sylvatica L.), дуба (Quercus robur L.) и липы (Tilia europaea L.). Испытания проводились на образцах в абсолютно сухом состоянии, кондиционированных при 20С/65 RH и 20С/90 RH и пропитанных водой при варьируемой скорости подачи тонко-го бурового сверла 0.5, 1.0 и 1.5 м/мин и фиксированной частоте его вращения 2000 мин-1. Получены линейные модели определения плотности, модуля упругости и прогнозирования предела прочности древесины при статическом изгибе на основании данных сопротивления сверлению и подаче. Выявлено отсутствие статистически значимого влияния влажности древесины на определение модуля упругости методом измерения сопротивления сверлению. Значимое влияние влажности для определения плотности древесины установлено для образцов влажностью выше и ниже предела насыщения клеточных стенок. Максимальный эффект на коэффициент детерминации для линейных моделей определения плотности и модуля упругости древесины методом измерения сопротивления сверлению оказывает по-рода древесины. Для всех условий эксперимента сопротивление древесины сверлению являлось оптимальным параметром по сравнению с сопротивлением подаче, обеспечивающим максимальную точность (R2) определения плотности и модуля упругости древесины методом измерения сопротивления сверлению. Предполагается, что установленные моде-ли взаимосвязи между сопротивлением древесины сверлению, модулем упругости и плотностью древесины могут быть использованы для оценки физико-механических свойств и внутреннего состояния древесины для радиального и тангенциального направлений сверления относительно направления волокон. Mobile tool for wood properties evaluation by the drilling resistance measurements method IML-Resi PD-400 and standard drill bit (IML System GmbH, Wiesloch, Germany) were used for the investigation of correlation between drilling and feeding resistance with density, modulus of elas-ticity and modulus of rupture for defect free Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.), English oak (Quercus robur L.) and Common lime (Tilia europaea L.). Tests were conducted on specimens, which were oven-dried, conditioned at 20 C /65 RH and 20 C /95 RH, and vacuum-impregnated with water at varied feed rates - 0.5, 1.0 and 1.5 m/min and constant drill bit rotational frequency 2000 min-1. Linear models were found for evaluation of density and modulus of elasticity and prediction of modulus of rupture by the drilling and feeding resistance. The impact of the wood moisture content on the evaluation of modulus of elasticity by the drilling resistance measurements was not significant. Effect of moisture content on density evaluation was found for specimens with moisture content above and below the water satura-tion point. The maximum influence on the coefficient of determination for linear models for den-sity and modulus of elasticity evaluation by the drilling resistance measurements had a wood species. For all tests conditions, the drilling resistance was the optimal parameter compared to the feeding resistance providing higher predictive power (R2) for models for density and modulus of elasticity evaluation. It is assumed that the established linear models of the interaction be-tween drilling resistance, modulus of elasticity and density can be used for prediction the internal conditions, physical and mechanical properties of wood for radial and tangential drillings direc-tion in relation to the wood grain direction.

An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles that were industrially vacuum-pressure-impregnated with a copper-based preservative (Korasit KS-M) and untreated reference poles. Both types of poles were subject to 10.5 years of in-ground exposure. Wood moisture content (MC) was measured using a resistance-type moisture meter. MC varied between 15% and 60% in the radial and axial directions in both treated and untreated poles. A higher MC was detected in the underground, top, and outer (sapwood) parts of the poles. Typical drilling-resistance (DR) profiles of poles with internal defects were analyzed. Preservative treatment had a significant influence on wood durability in the underground part of the poles. Based on DR measurements, we found that untreated wood that was in contact with soil was severely degraded by insects and wood-destroying fungi. Conversely, treated wood generally showed no reduction in DR or feeding resistance (FR). DR profiling is a potential method for the in-situ or in vitro assessment and quality monitoring of preservative treatments and wood durability. The technological benefits of using drill bits with one major cutting edge, instead of standard drill bits with center-spiked tips and two major cutting edges, were not evident. A new graphical method was applied to present DR data and their spatial distribution in the poles. Future studies should focus on the impact of preservative treatments, thermal modification, and chemical modification on the DR and FR of wood. This may further elucidate the predictive value of DR and FR for wood properties.

Tangible cultural heritage artifacts (e.g., archeological sites, historical buildings, monuments, and statues) can suffer severe deterioration upon exposure to external stresses (human-, or environment-derived) through the centuries. Hence, the implementation of effective conservation and consolidation strategies is necessary. A distinctive part of these is the design, preparation and application of functional chemical consolidants. In this paper we report on the synthesis and characterization of a multipodal polyhedral oligomeric silsesquioxane (POSS) with 16 protruding phosphonate groups (PHOS-POSS) that are grafted to the Si8O12 cage-like silsesquioxane core. A diphosphonate (PAPTS) containing a polymerizable silanetriol unit has been synthesized, as a small molecule partial analog of PHOS-POSS. PHOS-POSS is a potent consolidant for gypsum stones, as proven by drilling resistance measurements on artificial model gypsum specimens. This mineral was chosen because it has been used since the ancient times as a structural material (e.g., in the Minoan Palace of Knossos, Crete, Greece). It achieved more than a 1000-fold increase in drilling resistance, while exhibiting high penetration depth (>40 mm). PAPTS, on the other hand, is a much weaker consolidant (enhancing drilling resistance by a factor of 2), most likely due to the low number of phosphonate groups (two). Based on structural correlations with several calcium phosphonate networks and structure solution of the compound Ca-methylamino-di-(methylenephosphonate) (Ca-C1D), it is proposed that the high consolidation efficiency of PHOS-POSS is ascribed to its high affinity for Ca sites on gypsum (ability to substitute the surface Ca2+-bound water molecules), and to the random substitution of sulfate groups in the structure of gypsum.

Limestone sourced from Salisbury Cathedral and Bath Abbey (UK) was treated with commercially available nanolime of concentration 25 g/l. The response of the stones to the treatment was studied using a variety of analysis techniques including optical microscopy, electron microscopy, drilling resistance measurement and mercury intrusion porosimetry. Weathered and non-weathered surfaces of both types of stones were compared. All the specimens were characterised before and after the treatment to determine any changes in their properties caused by their weathering and by the treatment itself. Results show that the degradation processes of the stones strongly affect their interaction with nanolime consolidation treatments. Drilling resistance measurements of treated and untreated samples were compared. After 20 days significant increases in sub-surface drilling resistance was observed in the non-weathered Bath stone and a small increase in the weathered Bath stone after 6 months was also noted. Both weathered and non-weathered Chilmark stone showed an increase in drilling resistance after 6 months, however at 20 days this was most evident in the samples treated with nanolime in isopropanol as opposed to ethanol.

This data set contains the raw data used to plot Figures 4, 5, 6, 7 and 8 from the paper. These are clearly identified in the spreadsheet alongside the relevant data. A more detailed description is provided below. The dataset provide the raw data used to produce a plot of average drilling resistance versus hole number in an artificial reference stone which was used for wear-correction purposes. (see figure 4) Data used to produce a summary of drilling the data processing methodology used is also provided. This consists of drilling resistance against depth for three representative trials performed on Bath stone at 10 mm/min penetration rate and 600 RPM. The depth specific average resulting from averaging each of the three trials at each particular depth is shown. (see figure 5) Data showing the variation of average drilling resistance with penetration rate and rotational speed on a Bath stone and artificial reference stone is provided. (see figure 6) Data showing the linear relationship between radius-independent average drilling resistance and different PR/RPM settings on Bath stone and artificial reference stone is provided (see figure 7) The coefficient of variation at different PR/RPM settings on Bath stone and artificial reference stone is given.

Использование различных параметров, характеризующих свойства древесины, в устройствах, основанных на измерении сопротивления древесины сверлению, делает невозможным сравнение, а также снижает уровень научной составляющей результатов измерений. В качестве выходных, универсальных параметров, характеризующих процесс сверления и свойства древесины, может быть использована мощность сверления и подачи (Вт). Для сравнительного анализа работы были использованы устройства для измерения сопротивления древесины сверлению IML-RESI PD 400 (IML SystemGmbH, Вислох, Германия) и устройство для измерения мощности сверления ResistYX (ООО НовЛесТех, Йошкар-Ола). В результате последовательных просверливаний образцов из древесины сосны (Pinus sylvestris L., Pinus ponderosa Dougl. ex Laws.), бука (Fagus sylvatica L.), дуба (Quercus robur L.) и березы (Betula pendula L.) с нормализованной влажностью определены коэффициенты, рассчитываемые как отношение средних величин сопротивления древесины сверлению (%, PD-400) и мощности сверления (Вт, ResistYX). Установлено, что порода древесины оказывает значимое влияние (p=0,05) на средние значения коэффициента среди групп образцов. Определена достаточная степень сходимости результатов замеров, полученных при использовании тестируемых устройств по амплитуде и глубине просверливания. При сравнении результатов замеров сопротивления древесины просверливанию и мощности сверления, полученных при использовании различных устройств, необходимо учитывать скоростные характеристики процесса: скорость вращения и подачи бурового сверла, оказывающие влияние на величину подачи на главные режущие кромки. На основании результатов просверливаний всех образцов получена линейная модель (R2=0.99) взаимосвязи сопротивления древесины просверливанию (устройство PD-400) и мощности сверления (устройство ResistYX). Предложенная модель может быть использована для преобразования и сравнения данных сопротивления древесины сверлению и мощности сверления, полученных с использованием тестируемых устройств. The use of different parameters for wood properties evaluation by the drilling resistance measurements makes difficulties in data comparison, and also reduces the level of scientific component of the results. Drilling and feeding power (W) can be used as universal output parameters which characterize the drilling process and properties of wood. An IML-RESI PD 400 (IML System GmbH, Wiesloch, Germany) and ResistYX (LLC NovlesTech, Yoshkar-Ola, Russian Federation) drilling tools were used for comparative analysis. Laboratory drilling resistance experiments were conducted using a standard spade drill bit (IML System GmbH) and defect free specimens of Scots pine (Pinus sylvestris L.), Ponderosa pine (Pinus ponderosa Dougl. ex Laws.), European beech (Fagus sylvatica L.), English oak (Quercus robur L.) and birch (Betula pendula L.). Specimens were conditioned in normal climate (20 C/65%RH). Ratio coefficients between mean drilling resistance (%, PD-400) and drilling power (W, ResistYX) were calculated for each specimen. It was found that wood species has a significant effect (p=0.05) on the mean ratio coefficient of wood drilling resistance and drilling power. A sufficient degree of convergence between drilling resistance and drilling power in terms of amplitude and drilling depth was found for every separate specimen. Rotational speed and feed rate of drill bit influence the nominal chip thickness (feed rate per major cutting edge) and should be taken into account for comparison of results obtained from used drilling tools. Linear correlation (R2=0.99) was found between mean drilling resistance (PD-400) and drilling power (ResistYX). The model can be used for the results of the drilling resistance and drilling power converting or comparison obtained from the tested drilling tools.

Semi-non-destructive drilling resistance instruments have been widely adopted for timber testing and forestry for wood quality assessments. The accuracy of a drilling resistance tool for predicting wood density may be affected by needle (drill) wear, and there is limited information regarding the wear behaviour of drill bits in wood resistance drilling. It is unknown when changes in needle sharpness and diameter become critical for quantifying wood density. To measure the effect of Resi needle wear, an IML Resi PD 500 was used to obtain cross-sectional traces of Southern Pine (Pinus elliottii var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze)) average outerwood density: 519 kg/m³ and Spotted Gum (Corymbia citriodora subsp. variegata (F. Muell.)) average outerwood density: 779 kg/m³ logs. Southern Pine was tested with feed speeds of 200 cm/min at 3500 rpm and 100 cm/min at 5000 rpm. Spotted Gum was tested with a feed speed of 70 cm/min at 5000 rpm. A new needle was used for each setting. The effect of needle wear was tested after 0, 100, 200, 300, 400, 500, and 600 m of drilling depth. There was no effect on drilling resistance values up to 600 m of drilling length with feed speed 200 cm/min and 3500 rpm settings for Southern Pine. This would result in 2000 drilling measurements of 30 cm diameter trees. With alternative setting for Southern Pine with a setting of 100 cm/min feed speed and 5000 rpm, the increase in amplitudes was not significant until 300 m of drilling, after which, at 400 m, the amplitude increased by 2% (9.8 kg/m3), and after 600 m, the amplitude increased by 3.1% (15.2 kg/m3). For the hardwood Spotted Gum, the amplitude decreased by 0.9% (2.3 kg/m3) after 100 m, and after 300 m, the amplitude decreased by 3.3% (8.2 kg/m3). After 300 m, it was not possible to drill Spotted Gum due to extensive needle wear. The study highlighted the importance of needle wear in resistance drilling, providing guidance for reliable needle use to improve measurement accuracy and wood quality assessment.

Consolidation of lime mortars with ethyl silicate, nanolime and barium hydroxide. Effectiveness assessment with microdrilling data