A Plastered Floor from the Neolithic Village, Yiftahel (Israel)

A plaster floor from a house in the PPNB site of Yiftahel is analyzed. The floor was made of almost pure lime with no added aggregates. It was built in two phases, a coarser base and a fine finish. The strength of this plaster equals that of a high modern cement.Analyse d'un sol en plâtre du site PPNB de Yiftahel. Ce sol est composé de plâtre presque pur, sans autre aggrégat. Il est formé de deux couches, l'inférieure plus grossière que la supérieure. La résistance de ce sol est comparable à celle des meilleurs ciments modernes.Ronen A., Bentur Arnon, Soroka Itzhak. A Plastered Floor from the Neolithic Village, Yiftahel (Israel). In: Paléorient, 1991, vol. 17, n°2. pp. 149-155

~.dvances in Cement andConcTEtf MEASUREMENT OF WATER TRANSPORT FROM SATURATED FUMICE AGGREGATES TO HARDENING CEMENT PASTE

In this study about internal curing of High Performance Concrete, X-ray absorption showed that considerable transport of water from saturated lightweight aggregates (pumice) to hydrating cement paste [water/cement (w/c) ratio 0.3] took place in the first days after casting and covered a distance of at least 4 mm. As a consequence, the amount of water released by the lightweight aggregates, rather than the spatial distribution of the aggregates, is in this case the crucial factor to avoid early-age self-desiccation shrinkage. INTRODUCTlON High strength cementitious materials are characterized by superior propenies in the hardened state. Yet, their application encounters some difficulties, in panicular due to sensitivity to earlyage cracking, which is associated with sell-desiccation and autogenous shrinkagle (1). Conventional curing techniques are not always effective in eliminating cracking, since the water migration into the concrete is limited by the tightness of the cement paste (2)