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Use of pumice and scoria aggregates for controlling alkali silica reaction

Tapan M.

Physicochemical Problems of Mineral Processing

2014

Vol. 50, iss. 2

467--475

Turkey has important potential pumices reserves (68% of the reserve of the world) and 56 % of pumice reserve of Turkey is in the East Anatolia Region. It is important to assess huge pumice reserves in Eastern Turkey for its use in the cement and concrete industry. Use of acidic pumice and basic pumice (scoria) as cement additive or aggregate are gaining popularity because of their proven structural/durability properties. This paper presents the results of an investigation to assess the effectiveness of pumice and scoria aggregates in controlling alkali silica reaction (ASR) of alkali silica reactive aggregate using the following test methods: the accelerated mortar bar test (ASTM C 1260) and the scanning electron microscopy technique (SEM). The morphologies, structures and properties of the samples were determined by XRD, ICP-MS, XRF and thin section study. Mortar cubes were specially prepared according to ASTM standards using 10, 20 and 30% pumice or scoria aggregate as alkali silica reactive aggregate replacement. The results are compared with ASTM requirements to assess the suitability of pumice or scoria for preventing alkali silica reactivity. According to the results of these methods, pumice aggregates control the alkali silica reaction whereas scoria aggregates decrease expansion but is not as effective as pumice in preventing ASR. The results of SEM analysis showed alkali silica gel formation and serious decomposition of aggregate texture due to ASR in scoria added mortar bars.

Chemical characterization of patnos scoria (Agri, Turkey) and its usability for production of blended cement

Depci T., Efe T., Tapan M., Ozvan A., Aclan M., Uner T.

Physicochemical Problems of Mineral Processing

2012

Vol. 48, iss. 1

303-315

This paper reports results of investigations on suitability of scoria (PTS), collected from Patnos (Agri) in Turkey, for blended cement production. Scoria (basic pumice) was chosen as cement replacement materials due to its availability and cost in Agri in Turkey. The portland cement was replaced by scoria within the range of 0, 5, 10, 20, 30, 40 and 50%. Characterization of scoria was subjected by the X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), BET surface area and porosity, zeta potential (?) and thin sections. The standard tests were conducted for the obtained fresh and hardened states of scoria blended cement paste. Furthermore, the obtained cements were characterized by the XRF. According to experimental results, scoria up to 20% ratio could be added into clinker and it has a good potential of manufacturing blended scoria cement.