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Via the links below you will find articles describing the results obtained by Dale P. Bentz, National Institute of Standards and Technology, USA with the use of the GNI X-Ray Absorption System at the Technical University of Denmark.

Article 1, Abstract
X-ray absorption and concurrent mass measurements are used in quantifying water movement in 4 mm to 5 mm thick cement paste specimens with their top surface exposed to drying. Experimental variables examined in this preliminary study include water-to-cement (w/c) ratio and open vs. capped samples. Keywords: Cement paste(D); Curing (A); Drying (A); Water movement; X-ray absorption

Link to article 1: http://ciks.cbt.nist.gov/bentz/xray

Article 2, Abstract
As concrete cures in the field, there is a constant competition for the mixing water between evaporation and hydration processes. Understanding the mechanisms of water movement in the drying/hydrating cement paste is critical for designing curing systems and specialized rendering materials, as well as for selecting repair materials and methodologies. In this work, X-ray absorption measurements indicate that fresh cement paste dries uniformly throughout its thickness, as opposed to exhibiting the sharp drying front observed for most porous materials.

Link to article 2: http://ciks.cbt.nist.gov/bentz/drying

Article 3, Abstract
Fundamental studies of the early age desiccation of cement-based materials with and without a shrinkage-reducing admixture have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption to map the drying profile, internal relative humidity, and autogenous deformation. Keywords: Cement paste (D); drying (A); humidity (A); shrinkage (C); surface tension.

Link to article 3: http://ciks.cbt.nist.gov/bentz/srapaper
The X-ray absorption systems described below are not a part of GNI ApS or GNI ApS' product, service or support program. The X-ray absorption systems are supported by Gorm G. Nielsen and for any questions please call: +45 21 23 39 33 or mail: ggn@gni.dk.

The system works by measuring the X-ray absorption for a given material. This is done by exposing the material/sample to X-ray and use a detector on the other side to measure the resulting spectrum. The user software runs under Windows 2000 XP and takes advance of all the features of a modern PC, CD-ROM recorder, Intranet connection, Joystick, etc. In addition to this the system has two software packages included for advanced analysis. One for experiments setup, with the aim of eliminating the numbers of variables and one for multivariate analysis. The hardware consist of two units, the PC and the test chamber. The test chamber has all the necessary hardware for the 3-D manipulation of the X-ray and detector in order to make measurements on several different samples.
X-ray Absorption System