Thermodynamic predictions of changes during cement hydration, or the effect of mineral additions such as limestone, silica fume, coal fly ash, blast furnace slag or calcined clay on composition and volume of hydrates may lead to a more substantial understanding of observable changes in compressive strength and/or durability, which can be used in further optimisation of cement recipes. In particuar, calculations of the kind, amount and volume of potentially formed hydrates can be used for identifying promising additions and blends before the experimental verification.
About Nanocem internal project "CemGEMS"¶
The project, started in May 2018, foresees incremental development of CemGEMS as an innovative, extensible, user-friendly, efficient and responsive web app that, in a simple and intuitive way, allows a cement chemist or engineer to model hydration for typical cement paste recipes at varying water/binder mass ratio, temperature, and composition, including the addition of SCMs, ingress of salts, carbonation, leaching in water or salt solution.
On the back-end (or server side), CemGEMS uses the GEMS3K code (wrapped into xGEMS API) with PSI-Nagra and Cemdata’18 chemical thermodynamic databases. User profile accounts and user-created documents (recipes, processes, plots) can be automatically stored in the database and accessed later from other browsers, computers and locations.
On the front-end (or client side), the CemGEMS web app is accessible by the user anytime anywhere via secure web protocol (SSL) in a web browser on any device – from desktop PCs to laptops and tablets; it can adjust itself to device parameters and screen geometry; there will be no need for installations or upgrades.
About Nanocem internal project "CemGEMS extension"¶
In March 2020, before completion of the CemGEMS project development, a testing session involving 28 users who signed in to date, has been launched by distributing two questionnaires - one regarding the web app applicability for cement chemists and engineers (87 questions) and another on the usability of web app technical side (42 questions). There were 7 focus groups of test users; one user per group finally returned the feedback in early April 2020. On the basis of ranking critical comments and urgent needs, a "to do" list containing ca. 70 issues was compiled. The most important one was a demand to simplify and streamline the user's workflow, so that the relationships between recipes, processes and plots were maintained not by the user, but by the web app itself. This issue and ca. 30 others have been resolved by the development team within 2 months (from mid-April until mid-June 2020), in the course of preparation of CemGEMS release v.0.4.0 beta.
During the development and testing of CemGEMS, two other needs were identified that went beyond the current project and could be only satisfied in an extension of CemGEMS development with additional funding. One need is of scientific/engineering nature and consists in adding the calculations of isothermal heat generation or the adiabatic temperature rise upon cement hydration. Another need is to produce a CemGEMS web app variant dedicated to sensitive-data applications in cement industry, which should reside on a separate web server domain for commercial use. The aim is to perfor GEM simulations directly in the web browser on the user device connected via p2p data exchange with others inside of a given company network, so that the sensitive data would never leave the organization to be stored on a central server.
Identifications of these needs, that should make CemGEMS web app a complete and valuable service for research and industrial organizations affiliated to Nanocem consortium, resulted in a "CemGEMS extension" internal project proposal, submitted in early 2020 and approved in late April 2020 as part of the vote during the Nanocem spring (video)meeting. The work on this extension project will start from July 1, 2020, after CemGEMS version 0.4.0 beta release by the end of June. This work is expected to end up in a release of CemGEMS v.1.0 web app and its commercial counterpart by the end of 2020.