Feasibility of using a lignin-containing waste in asphalt binders

"Published online: 30 January 2019"A lot of water waste streams are produced during the production of hardboard panels. This paper analyses the feasibility of using a lignin-containing waste from the hardboard industry in asphalt binders. It would contribute to both waste reduction and decrease of the consumption of asphalt in order to obtain environmental, economic and social benefits. The waste from the hardboard industry was not subjected to any transformation i.e. it was blended directly with the conventional asphalt. Asphalt binder samples blended with 0, 5, 10, 20 and 40% of the waste were aged in a rolling thin-film oven apparatus. Basic characterisation (penetration grade, ring and ball softening point and resilience) as well as advanced characterisation (dynamic viscosity, shear complex modulus and phase angle) were performed. Asphalt binders blended with up to 20% waste can be stored, pumped and handled at hot-mix asphalt facilities. Addition of the waste to asphalt binder increases the viscosity and the shear complex modulus and reduces the phase angle. The waste produces asphalt binders with higher storage modulus and lower loss tangent. The waste enhances fatigue and rutting resistance. Asphalt binder with 20% of waste displays the best potential for use as an extender and as well as an enhancer in asphalt pavements. The research results can offer technical support to value this waste from hardboard production, without the need for subsequent transformations.(undefined

Accounting for Projection Bias in Models of Delinquent Peer Influence: The Utility and Limits of Latent Variable Approaches

Projection effects have been shown to bias respondent perceptions of peer delinquency, but network data required to measure peer delinquency directly are unavailable in most existing datasets. Some researchers have therefore attempted to adjust perceived peer behavior measures for bias via latent variable modeling techniques. The present study tested whether such adjustments render perceived peer coefficients equal to direct peer coefficients, using original data collected from 538 young adults (269 dyads). After first replicating projection effects in our own data and examining the degree to which measures of personal, perceived peer, and direct peer violence represent empirically distinct constructs, we compared coefficients derived from two alternative models of personal violence. The first model included an error-adjusted latent measure of perceived peer violence as a predictor, whereas the second substituted a latent measure of directly-assessed, peer-reported violence. Results suggest that personal, perceived peer, and direct peer measures each reflect fundamentally separate constructs, but call into question whether latent variable techniques used by prior researchers to correct for respondent bias are capable of rendering perceived peer coefficients equal to direct peer coefficients. Research cannot bypass the collection of direct peer delinquency measures via latent variable modeling adjustments to perceived peer measures, nor should models of deviance view perceived peer and direct peer measures as alternative measures of the same underlying construct. Rather, theories of peer influence should elaborate and test models that simultaneously include both peer measures and, further, should attempt to identify those factors that account for currently unexplained variance in perceptions of peer behavior