Search the repository

A+ | A- | | SLO | ENG

Abstract: Carbon capture plays an important role in the decarbonation of the building sector. One way to capture carbon is through mineral carbonation, in which Ca and Mg compounds react with CO2 to form stable carbonate minerals such as calcite, dolomite, magnesite and/or siderite, permanently sequestering CO2. Various techniques are available to measure the amount of permanently bound CO2 and quantify the carbonation potential. The suitability and accuracy of a particular method are very important, as the accurate determination of CO2 is crucial to correctly assess the sequestration potential of different materials. This study compares the three methods: calcimetric, gravimetric and thermogravimetric analysis used for CO2 determination in different types of ash, slag and natural rock. While the CO2 content in natural rock is stable, the CO2 content in slag and ash can change over time as the contained minerals gradually absorb CO2 (by natural or accelerated carbonation) until they are fully carbonated. To avoid errors in testing the CO2 uptake, as-received samples were first exposed to the full carbonation process and then tested. The comparison of calcimeter, thermogravimetric and gravimetric analysis of ground and sieved samples with a particle size below 125 μm shows that the results usually differ by less than 2 %. Higher deviations could be caused by non-carbonate minerals (especially in slags) that can react with hydrochloric acid during the calcimetric and gravimetric tests and/or decompose in the range where carbonates decompose, contributing to inaccurate CO2 measurements. The measurement uncertainty was calculated for all three quantitative methods to allow a practical comparability.
Keywords: CO2 sequestration, ash, slags, natural rocks, TGA, calcimetry, measurement uncertainty
Published in DiRROS: 15.10.2025; Views: 509; Downloads: 336
Full text (5,06 MB)
This document has many files! More...
This document is also a collection of 1 document!

Abstract: The precise and accurate determination of sulphate levels in cement is of utmost importance due to the potential occurrence of internal sulphate attack in concrete, which affects the latter’s durability, and thus, also the safety of concrete constructions. The estimated measurement uncertainty provides a level of confidence in the experimental results, and enables the comparison of data, both between different laboratories and between different methods. This paper presents an alternative approach to the estimation of measurement uncertainty in the determination of sulphate in cement, based on the use of proficiency testing data. The calculations used in this procedure refer to the estimation of reproducibility within-laboratory component of the analysis of control samples, as well as of the bias component of sulphate content data for different types of Portland cement derived from several proficiency testing trials.
Keywords: cement, sulphate, measurement uncertainty, alternative approach
Published in DiRROS: 03.03.2025; Views: 710; Downloads: 565
Full text (366,74 KB)
This document has many files! More...

Abstract: The paper presents an evaluation of synchronization issues when performing material testing machine calibration using continuous loading. A procedure for the compensation of a rangewide error in calibrated force values is proposed based on a correction factor determined from static and transient errors difference at a chosen force step. The procedure was applied for a calibration of a testing machine with a 20 kN force transducer and 200 N/s to 2000 N/s loading rates. The results show good performance of the compensation technique, reducing calibration errors to below 1% in non-synchronized signals even under unknown filter and delay setting.
Keywords: force calibration, loading profile, measurement uncertainty, continuous loading
Published in DiRROS: 20.12.2023; Views: 1224; Downloads: 680
Full text (5,97 MB)
This document has many files! More...