Timber bridges require high accumulated maintenance costs, which can be many times greater than their initial cost. Infrastructure managers need deterioration models to assist with making appropriate decisions concerning repair strategies and program maintenance schedules by accurately predicting the future condition of timber bridge elements. Markov chain–based models have been used extensively in modeling the deterioration of infrastructure facilities. These models can predict the condition of bridge elements as a probabilistic estimate. This paper presents the prediction of future condition of timber bridge elements using a stochastic Markov chain model. Condition data obtained from the Roads Corporation of Victoria, Australia, were used to develop transition probabilities. The percentage prediction method, regression-based optimization method, and nonlinear optimization technique were applied to predict transition matrices and transient probabilities from the condition data. The most suitable ...

Circular-economy-based sustainability approaches in construction are gaining wide acceptance due to the volume of waste generation and increasing demand for natural materials. Propelled by the recent timber shortage in Australia and the issues of waste management of cardboard, this study aims to analyse the possibilities of using cardboard as a construction material, based on its initial strength and multiple recycling options. A systematic review of research papers published in the last 40 years has been undertaken using a single keyword search to select the database. The review is presented in terms of the characteristics of the cardboard, dimensional stability, durability, structural strength, design, and analysis of cardboard. Recurring themes are evaluated using a latent Dirichlet allocation approach to identify the factors that ascertain the suitability of cardboard. Analysis reveals that despite certain constraints, such as water absorption and fire resistance, cardboard can be used as a replacement for timber by overcoming such limitations. This observation has benefits for the construction industry and the recycling industry. This study found that cardboard adheres to the circular economy principles, which should inspire policymakers. The paper concludes by highlighting the current circumstances and scientific challenges that impede the usage of cardboard in construction and recommends potential works needed to address these challenges for the benefit of practitioners and researchers.