This paper focuses on monitoring setting and strength development in cemented paste backfill (CPB). The composition of the paste is altered to study the effects of binder type and content, selected chemical admixtures (superplasticizers), mineral additives (e.g., fly ash), and pore fluid chemistry (e.g., ionic concentration and pH) on these properties. The three main techniques utilized are shear wave velocity measurements, penetration tests (e.g., Vicat needle tests), and unconfined compressive strength tests. All of these tests are sensitive to changes in the paste composition. The effect of the pore fluid chemistry and the chemical additives on the CPB properties depends on the ion type and concentration and the chemical composition of the superplasticizers. The shear wave velocity in both uncemented and cemented pastes increases with time as a result of self-weight consolidation, capillary forces, and cementation (the precipitation of ions in uncemented tailings pastes or cement hydration in cemented tailings pastes).Résumé : Cet article se concentre sur le montage d'instrumentation et sur le développement de la résistance dans un remblai de pâte-ciment (CPB). La composition de la pâte est modifiée pour étudier les effets sur ses propriétés du type et de la teneur du liant, des mélanges chimiques sélectionnés (superplastifiants), des additifs minéraux (e.g., cendres volantes), et de la chimie du fluide interstitiel (e.g., concentration ionique et pH). Les trois principales techniques utilisées sont les ondes de cisaillement, les essais de pénétration (e.g., essais à l'aiguille Vicat) et les essais de résistance en compression simple. Tous ces essais sont sensibles aux changements dans la composition de la pâte. L'effet de la chimie du fluide interstitiel et des additifs chimiques sur les propriétés du CPB dépend du type et de la concentration d'ions, et de la composition chimique des superplastifiants. La vitesse des ondes de cisaillement tant dans les pâtes cimentées que non cimentées augmente avec le temps à cause de la consolidation sous son propre poids, des forces capillaires et de la cimentation (la précipitation des ions dans les pâtes de stériles non cimentées ou l'hydratation du ciment dans les pâtes de stériles cimentées).Mots clés : remblai de pâte-ciment, vitesse des ondes de cisaillement, montage, résistance en compression simple.[Traduit par la Rédaction] Klein and Simon 324

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Oviraptorosaurs, like many coelurosaurians, are frequently diagnosed using incomplete or fragmentary skeletal remains, with factors such as body size often used to assign material to a particular taxon or as a basis for describing new species. Here we describe a partial skeleton, ROM VP 65884, from the Hell Creek Formation (Montana, USA), and through morphological and phylogenetic comparisons identify it as belonging to Caenagnathidae, and probably referable to Anzu wyliei. We perform multi-element osteohistological sampling of the tibia, fibula, manual phalanx, rib and gastralium of ROM VP 65884 to determine the ontogenetic status of the individual, and to perform a detailed assessment of the intra-skeletal variation present in a series of histological proxies for growth and development. Skeletochronological analysis suggests ROM VP 65884 was still actively growing at time of death. Lacunar area was variable, but consistent with values reported for other dinosaurs and vertebrates. Osteocyte lacunar density was found to be relatively similar to the few previous measurements known from coelurosaurian dinosaurs, and preserved no ontogenetic pattern. Osteocyte lacunar density (OLD) was much higher in sampled rib and gastralia elements when compared to limbs, and the high variability in OLD overall lends further support against the hypothesis of this feature acting as a proxy for mass-specific growth rate. Our results stress the importance of using osteohistological analyses to constrain variation and permit ontogenetic assessment, and suggest caution be taken when using size as a determinant for referral of disassociated elements to specific or new coelurosaur taxa.

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The fossil record of caenagnathid oviraptorosaurs consists mainly of their fused, complexly sculptured dentaries, but little is known about the growth and development of this diagnostic structure. Previous work has suggested that the ridges and grooves on the occlusal surface are either the vestiges of teeth and their alveoli or were adaptations to increase shearing action during mastication. In addition, the distinctiveness of the dentaries has led to their use for species‐level taxonomy, without a complete understanding of their variation through ontogeny. Here, we describe additional caenagnathid mandibles from the Dinosaur Park Formation of Alberta, Canada, and perform histological analyses to assess relative ontogenetic stage and the nature of the occlusal elaborations. The results show that the mandibular symphysis is synostosed early in ontogeny and does not accurately reflect ontogenetic stage in caenagnathids. In contrast, the presence of cyclical growth marks in a large specimen shows that mandibles can be used for relative histological maturity estimation. Histological features of the ridges of bone surrounding the lingual groove indicate that they are not the vestiges of tooth‐bearing tissues and that caenagnathids did not lose their teeth through ontogeny as suggested in previous work. Instead, increased secondary remodeling in these structures is consistent with their use for food processing. Unexpectedly advanced maturity in a small specimen suggests that at least three caenagnathid species of varying body sizes coexisted in the Dinosaur Park Formation. These results stress the necessity of histological analysis when assessing maturity or ontogenetic trends in fossil material. Anat Rec, 303:918–934, 2020. © 2019 Wiley Periodicals, Inc.

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