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• GIS analysis is conducted to quantify the hydrological information for mud pumping prediction. • In-service train data and hydrological variables are combined to develop predictive model. • Incorporating hydrological variables can improve prediction performance. • Explainable deep learning can be used to reveal the effects of a single variable on the probability of mud pumping. • The most vulnerable sections for mud pumping in railway tracks can be identified. Automatic and timely identification of mud pumping is important for the reliability and safety of railroads. The current mud pumping prediction model is based on monitoring the dynamic response of railway tracks. The essential geotechnical trigger factors such as the hydrological conditions are not well-considered in these prediction models, as that information is hard to be quantified, which unavoidably reduces the accuracy of the prediction. This paper proposes to utilize the Geographic Information System (GIS) to quantify the hydrological information along railway tracks. Through GIS analysis, the hydrological variables including elevation, near-river distance, rainfall, sink depth, and soil types are estimated and combined with in-service train monitoring data for model development. To deal with multi-attribute data, a dual-channel neural networks model is proposed to separately mine the characteristics in different attributes data for prediction. To further understand the prediction model, Shapely addictive explanations (SHAP) method is applied to estimate the importance of hydrological variables and reveal the possible relationships between the variables and the probability of mud pumping. The proposed approach is applied to a real-life case from the railway tracks in Australia to validate its effectiveness. The prediction results show that the proposed approach can predict mud pumping with balanced accuracy of 90.84%. The results confirm that integrating of GIS information and monitoring data can generate more accurate prediction and reduce the false prediction rate. Based on the explainable results, it is observed that rainfall is the most important hydrological variable that influences mud pumping occurrence. Apart from rainfall, groundwater-related variables show a greater impact on mud pumping occurrence than surface water-related variables. The explainable results also can help infrastructure managers to identify the most vulnerable sections in railway tracks, which facilitates targeted maintenance planning and track substructure design. [ABSTRACT FROM AUTHOR]

In this paper, a systematic machine learning strategy is proposed to classify wood properties based on a contact ultrasonic testing results. As such, several aspects of the wood material including the type of wood (hardwood or softwood), the direction of an ultrasonic test with respect to the growth rings of the wood, and, whether the wood is damaged or intact are investigated. As a pre-processor, the Variational Mode Decomposition technique is applied to the nonlinearly modulated ultrasonic signals, and the centre frequencies of the decomposition results are taken as features for Machine learning Algorithms (MLAs). Then with each of the MLAs, hyperparameter settings were optimised and technical aspects of the feature engineering are discussed. Best results were achieved using Ensemble classifiers, SVM, and KNN using three features/decomposition. To explore the physics behind the nonlinear problem, the relative false discovery rate obtained from the confusion matrix associated with applying the MLAs is proposed as a metric. We show that different features are capable of exploring different aspects of the problem better. The techniques of this paper can be applied to quality assessment of wood materials. The paper also demonstrates the capability of MLAs in exploring some physics of such problems. Moreover, billets with natural imperfections harvested from the site Collie in WA, Australia are classified to demonstrate the applicability of the proposed approach in real world problems. The result of 94% 5-fold cross-validation accuracy indicates the effectiveness of the proposed approach. • Contact ultrasonic technique is used for the wood quality assessment. • The Variational Mode Decomposition is used to decompose ultrasonic signals. • time–frequency features of the decomposed signals are used as features. • Machine learning algorithms are used to solve classification problems. • Some physics of the problem has been explored from the machine learning results. [ABSTRACT FROM AUTHOR]

Highlights • A historically significant metallic bridge in Australia was strengthened using CFRP composites. • Laboratory tests were conducted to develop nonprestressed bonded and prestressed unbonded systems. • Installation complexity and performance of the two developed systems were compared. • Short-term truck loading results and long-term wireless sensor network measurements are discussed. • Diurnal temperature changes caused significant thermal-induced stress cycles in the nonprestressed bonded system. Abstract This paper summarizes the strengthening of a historically significant 122-year-old roadway metallic bridge using nonprestressed bonded carbon fiber reinforced polymer (CFRP) plates. Prior to the bridge strengthening, sets of laboratory tests were conducted to characterize the mechanical properties, glass transition temperature, and CFRP-to-steel bond strength of two different epoxy adhesives (linear and nonlinear) commonly used for structural retrofitting. Furthermore, the field application complexity, as well as the short- and long-term efficiency of the developed nonprestressed bonded system, was compared with the existing flat prestressed unbonded retrofit (FPUR) system. Short-term measurements, including sets of truck-loading tests performed before and after strengthening, demonstrated that the tensile stresses were reduced by approximately 15% and 44% in the bridge cross-girders after strengthening by the proposed nonprestressed bonded and FPUR systems, respectively. The long-term measurement results, obtained from a wireless sensor network (WSN) system installed on the bridge, revealed that because of the mismatch of the steel-CFRP thermal expansion coefficient, diurnal temperature changes can cause significant thermal-induced stress cycles in the nonprestressed bonded CFRP plate. These diurnal cyclic stresses must be considered in the design of bonded CFRP strengthening solutions. [ABSTRACT FROM AUTHOR]

Veneer Based Composite (VBC) hollow sections are currently being developed in Australia as alternative products to sawn timber. However, due to the limited log length that peeling lathes can accommodate, solutions to manufacture long sections need to be investigated to create useable beams and columns. This paper experimentally assesses the bending capacity of three different concepts. Two concepts consist of manufacturing short sub-sections and connecting them together with (i) a sleeve inserted into the hollow-form and (ii) wrapping Fibre Reinforced Polymer (FRP) around the sub-sections at the connection. The third concept consists of manufacturing the sections in a continuous process, similar to LVL products. Three sets of four nominally identical circular hollow sections (1.2 m long, nominal 76.1 mm internal diameter and 15 mm wall thickness) were manufactured from Hoop pine ( Araucaria cunninghamii ) veneers. In each set, one section was used as the reference capacity, two sections were cut in half with the two halves being connected back together with either an aluminium sleeve or Glass Fibre Reinforced Polymer (GFRP). The last section had the veneers staggered and end joined, to mimic a continuous manufacturing process. Once cured the sections were then tested in four points bending. The sleeved sections were found to have the lowest bending capacity, while the GFRP and continuous sections reached more than 80% of the capacity of the reference sections. The latter two designs, therefore offer a potential solution for creating useable lengths of VBC hollow sections. Further research is required to refine and validate the design. [ABSTRACT FROM AUTHOR]

Two new Australian Standard methods to test alkali-silica reactivity (ASR) of aggregates – AS 1141.60.1 accelerated mortar bar test (AMBT) and AS 1141.60.2 concrete prism test (CPT) were published in September 2014. The methods adopted test procedures correspondingly from ASTM C1260 and ASTM C1293 with improved performance limits leading to a new class of slowly reactive aggregates. This paper examines the accuracy of these new testing methods in predicting the ASR of aggregates in field conditions based on international research data. AS 1141.60.1 was found to be a relatively good accelerated test which correctly classified ‘slowly reactive’ and ‘reactive’ aggregates consistent with field performance with few exceptions. It is however a poorer screening test for non-reactive aggregates than ASTM C1260. Both AS 1141.60.2 and ASTM C1293 concrete prism tests were found to be more reliable than AMBT as both correctly classified almost all 64 aggregates against known field performance. [ABSTRACT FROM AUTHOR]

• Existing gap in determining effects of timber structure/species on MTP moisture properties. • Hot and humid climate effects on MTPs moisture properties pre/post-construction. • MTPs composite structure, glue line and species influences on wetting/drying process. • Better moisture management of MTPs avoiding decay development and structural failure. This paper summarises the existing literature on water ingress and egress concerns in mass timber products. The main emphasis of this review paper is to identify and present the existing gap in knowledge regarding mass timber products' water absorption and desorption characteristics in comparison with the information available for solid wood. The paper also focuses on highlighting the need for further studies on climate effects on mass timber products, particularly in relation to hotter and more humid environments. The paper concludes that existing knowledge in this field mainly concentrates on wood species from North America and Europe under temperate conditions, while major climate differences in Australia and other similar climatic regions, could have dissimilar effects on the in-service performance of mass timber products. This review includes details of testing experiments and techniques used to model and monitor water gain in mass timber products and identifies an existing gap in unified methods for testing and sampling. The review also outlines a plan for defining water ingress and egress characteristics of mass timber products in the Australian climate. This review is a part of a larger project focusing on water ingress and egress issues in mass timber buildings in tropical and sub-tropical climates of Australia as part of the National Centre for Timber Durability and Design Life (NCTDDL) research program. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on the investigation into the performance of a microsyenite rock containing siderite, as a secondary mineral phase, from the disused Mt Gibraltar quarry in the Bowral district, 100km south-west of Sydney in New South Wales, Australia. Such a rock has been extensively used in the past as a dimension stone for a number of major building facades, curbstones and pavements in Sydney. Laboratory and field exposures of stone samples, conducted under controlled or measured environmental conditions, have shown through petrography that the siderite secondary mineral in the Mt Gibraltar stone is subject to alteration to iron oxides/hydroxides through oxidation processes. The rate of such alteration is generally slow to moderate, but is more profound in an alkaline environment. These findings are consistent with the theoretical desktop study of Eh–pH diagrams. Although the in situ oxidation of the siderite is visually observable, as pinhole-sized rust spots, the mobility of the iron and subsequent staining on the stone surfaces is negligible. Examination of existing structures in Sydney, built from siderite-bearing microsyenites, has confirmed some limited degree of in situ oxidation of the siderite to iron oxides/hydroxides. However, apart from some weathered veins and general browning of the stone with age, no visual defects were observed in structures with service lives of up to 80 years. Thus, the method developed can be used to assess similar rock sources as to the likely long-term iron-staining performance of dimension stone intended for external use. [Copyright &y& Elsevier]

• MDT of aged railway masonry arch bridge for masonry characterisation. • Influence of number of bed joints in the core samples on the compression strength. • High strengths of aged masonry than expected. • Comparison of mechanical properties obtained from flat jack and masonry core testing. • Digital Image correlation (DIC) technique as an efficient method for damage visualization and measurement. This paper aims to assess the strength of a 100 + year old masonry arch bridges in Australia that are currently in operation and routinely subjected to train loadings. Towards this end, 45 cores of 150 mm diameter with varied lengths and joint configurations were drilled from a typical bridge and tested. Out of these samples, 30 were tested under direct compression and 15 were tested for tensile strength with varying bed joint angles. The samples for compression testing were regularised by developing high strength mortar capping whereas, the samples for tensile strength were tested according to Brazilian testing method commonly used for evaluating the splitting tensile strength of materials. The typical failure mode of masonry under compression was due to vertical cracking in bricks, spalling and cracking in perpend joints. The average compressive strength of masonry was determined as 10.6 MPa. Young's modulus was also determined with a magnitude of 11,048 MPa which is comparable to an in-situ flat jack test conducted on the similar bridges. The increased number of perpend joints in masonry cores decreased the masonry compressive strength. Splitting tests revealed the average tensile strength of 1.34 MPa. From the results it can be concluded that the aged masonry used in the arch bridge has a higher strength than previously thought of and that the bridge seems to be capable of sustaining the current train loads, as observed at site. [ABSTRACT FROM AUTHOR]

• CO 2eq emissions of alkali- and lime-activated rammed earth (RE) were measured. • Recycled materials can be incorporated, reducing waste. • Use of a local base material is essential to reduce transport-related emissions. • Best material choices may vary with time and location. • Adopting alkali-activated RE could reduce Australia's greenhouse gas emissions. As the Paris Agreement target year of 2030 draws nearer, it is becoming increasingly evident that neither Australia nor many other nations are progressing at a rate sufficient to meet greenhouse gas emissions targets. One area in which to improve performance is in the use of low embodied energy construction materials. Rammed earth (RE) is often considered to be one such material. However, many modern RE variations incorporate cement: a significant contributor to global CO 2 emissions. RE materials with low greenhouse gas emissions have been developed as replacements for conventional construction materials. In this series, we examine the strength development, durability and sustainability, via life cycle assessment, of these new materials. This paper explores the cradle-to-gate greenhouse gas emissions of RE materials incorporating recycled waste (crushed brick and concrete), industrial by-products (ground granulated blast furnace slag, fly ash and silica fume) and either NaOH or hydrated lime. These are then compared to construction techniques conventionally used in Australia (cavity brick and brick veneer). Attributional life cycle assessments were carried out for hypothetical building envelopes suitable for climate zones 1–7, assuming construction in metropolitan Perth and 600 km inland (Kalgoorlie, WA). Results showed that greenhouse gas emissions per vertical square metre of wall could be reduced by 73% or 57% respectively when compared to traditional cavity brickwork or brick veneer. This is in contrast to RE incorporating cement, which produced a saving of just 15% compared to brick veneer. If this construction technique were adopted across Australia for new, detached dwellings constructed during 2021–2030, this could represent a greenhouse gas reduction of 11.3 million tonnes CO 2eq , or 1.2–1.3% of the cumulative emissions reductions required in 2021–2030 to meet Australia's Paris Agreement targets. [ABSTRACT FROM AUTHOR]

• Radiata Pine manufactured cross laminated timber (CLT) using heterogeneous lamella were investigated. • There was a good agreement in bending results of CLT between the theoretical methods and experimental tests. • Developed FE modelling technique could capture the structural performance of CLT. • Improved bending performance was observed for panels with thinner thickness. Cross laminated timber (CLT) is a sustainable and innovative engineered timber product validated as a viable alternative to more traditional construction materials like reinforced concrete and steel for use in mid-rise prefabricated construction. The structural response of CLT heavily relies on the species of timber used in manufacturing with feedstock varying significantly due to the original source and plantation stand. In Australia, Radiata Pine commonly used for general purpose structural timber mainly in residential house framing. Australia's largest CLT manufacturer, XLam, use Radiata Pine to produce panels for prefabricated construction. The present paper investigates the out-of-plane bending behaviour of 24 XLam CLT panels utilising four-point loading configurations. Experimental results indicated brittle failure modes when the samples were loaded along both the major and minor axes. In addition, plane cross-sections remain plane assumption were confirmed from the strain data obtained from the experimental tests. Various analytical methods (Timoshenko, Gamma (γ), K, and Shear Analogy methods) assessed the bending properties of the test samples, with the shear analogy method yielding the most accurate prediction. Other theoretical methods produced reasonable outcomes in accessing the effective bending stiffness together with bending and shear strengths. Finally, the bending properties of CLT were investigated using finite element analysis, which capture the overall behaviour of Radiata Pine CLT panels adequately. The effect of panel thickness was then examined numerically to observe its effect on bending. [ABSTRACT FROM AUTHOR]

• Geopolymer was repeatedly exposed to both hydrocarbon fluids (HFs) and high thermal cycles. • The 3-day old geopolymer was significantly attacked by HFs at high temperature. • Geopolymer suffered saponification and thermal cracks. • Crystalline mineral compounds in geopolymer were decomposed. • The 28-day old geopolymer experienced notably less saponification and thermal cracks. Geopolymer has already been used at a commercial airport, Brisbane West Wellcamp Airport (BWWA), and in mainline railway sleepers in Australia. It has also been proposed for use at military airbases to repair degraded concrete or any other special construction needs. Rigid pavements at military airbases, especially aprons, are frequently exposed to high thermal shocks by jet exhaust, and often get saturated by chemicals such as hydrocarbon fluids (HFs): aircraft's engine lubricating oil, hydraulic fluid and jet fuel. To promote wider and reliable use of geopolymer at military airbases, the resistance of geopolymer to both HFs and high thermal cycles should be thoroughly assessed. The present study investigates the resistance of fly ash (FA) based 3-day and 28-day old geopolymer mortars to both HFs and high thermal cycles simultaneously and separately. This study has identified that irrespective of the age of the geopolymer mortar, they experience saponification when expose to both HFs and high thermal cycles simultaneously. Soap and salt compounds, e.g., sodium carboxylate and sodium phosphates were identified in the geopolymer mortar after the saponification occurrence. The crystal lattices of the 3-day old geopolymer mortar were significantly affected and decomposed when exposed to HFs and high thermal cycles simultaneously. Upon 60 cycles of heat exposure, 3-day and 28-day old geopolymer mortar treated with HFs lost 42.52% and 33.85% of their compressive strength, respectively. The geopolymer mortar exposed to HFs at ambient temperature did not suffer from saponification process, and the reduction in the compressive strength was almost insignificant. The effect of high thermal cycles in reducing the compressive strength of the geopolymer mortar was substantial. This paper also reports mass loss characteristics, microstructures and degrading mechanisms of geopolymer mortar after exposure to HFs and high thermal cycles. [ABSTRACT FROM AUTHOR]

• Bending and shear behavior of Australian radiata pine cross-laminated timber. • FEM analysis to predict bending and shear strength of CLT. • Failure modes of CLT under out-of-plane bending and shear. • Comparison of bending and shear stiffness of CLT between tests and theoretical. Cross Laminated Timber (CLT) is increasingly being used in commercial and residential construction in Australia due to its inherent strength and sustainability credentials. Until recently, infrastructure building projects using CLT have been reliant on imported products from overseas manufacturers. There is now a viable Australian grown and fabricated CLT product from Radiata pine. This paper summarises the experimental results on the mechanical behaviour of Australian Radiata pine CLT panels in out-of-plane bending and shear. Three-layer 105 mm thick panels and five-layer 145 mm panels with three different spans were tested. The results demonstrate strong correlations to existing theoretical models and were used to validate the finite element model (FEM) developed in this research. The experimental results showed that the average bending stiffness of the CLT panels were marginally greater than theoretical values. The maximum bending strength for Radiata pine exceeded the characteristic strength of 14.0 MPa for grade XLG1 external laminas, with three-layer CLT samples averaging 28.7 MPa and five-layer CLT samples averaging 26.8 MPa. The maximum observed shear stresses ranged from 1.55 MPa to 2.18 MPa, which also exceeded the rolling shear characteristic strength of 1.2 MPa for the feedstock. The results also highlighted that the shear strength decreases with an increasing thickness of the CLT panel. [ABSTRACT FROM AUTHOR]