Experimental characterization of the constitutive materials composing an old masonry vaulted tunnel of the Paris subway system

A significant proportion of the Paris metro tunnels comprise a masonry vault built out of stone blocks and mortar joints, and sidewalls and slabs made of unreinforced concrete. In order to provide the necessary data for future structural evaluation, an extensive laboratory testing programme has been conducted to characterize the materials of the tunnel separately, i.e., mortar, stone, and concrete. The tests, carried out on specimens taken from cores extracted from a 1930s tunnel, enabled to determine the mechanical properties, including direct tensile, shear strength, and mode I fracture energy, as well as the properties of the stone-mortar interface. Results show that the masonry mortar joints could reach 10 cm in width, and that blocks of stone varied in composition and porosity, thus producing a wide range of mechanical properties. The concrete was composed of large-sized aggregates and showed low stiffness and strength. Based on these experimental results, ratios between mechanical characteristics are hereby proposed. Perspectives on the use of this experimental data in a finite element model are then discussed.     

新石器时期中原地区谷物加工技术初探

本文从考古发现的石磨盘、石磨棒中的石磨棒的形制入手,讨论了石磨棒的使用方式,指出滚压是史前粟脱壳加工的有效方式,揭示了中国先民7000年前就已经熟练运用滚压技术的事实。     

新密李家沟遗址发掘的主要收获

2009年秋季至2010年春季,北京大学考古文博学院与郑州市文物考古研究院合作发掘河南省新密市李家沟遗址,发现距今10500年至8600年左右连续的史前文化堆积.在堆积下部发现属于旧石器时代末期的典型细石器与局部磨制石锛陶片共存;中部则发现以压印纹粗夹砂陶与石磨盘等为代表的早期新石器文化;最上部是典型裴李岗文化遗存.     

Turning Stone into Bread: The Millstone Quarries of Medieval and Post-medieval Ireland

This article has two components; a discussion of an Ireland-wide inventory of millstone quarries and a detailed regional case study in order to study the development of the millstone industry at both micro and macro levels. The first component highlights the use of certain stone types used in Ireland and also uniformity in methods to extract each specific type of bedrock. Factors determining the commercialisation of millstones are also addressed. This is followed by intensive field-based investigation focusing on millstone quarries in Waterford Harbour in the south-east of the country. Research questions concerning geology, transport, typology, what techniques were used to transform a ‘rough-out’ piece, and the role individual quarries and local people played in the overall industrialisation of millstone production are addressed.