Ultra-high performance concrete (UHPC) was investigated in a recently published paper. Source: Ingo Bartussek– stock.adobe.com.
24. May 2018 | Application Areas
Importance of drying to control internal curing effects on UHPC
In a recently published paper, the interdependent relationships among hydration reaction, internal relative humidity, and strength of internally cured ultra-high performance concrete were investigated, to emphasize the importance of drying on superabsorbent polymer-based internal curing.
Experiments showed that the self-desiccation of ultra-high performance concrete (UHPC) cannot be prevented by external curing, such as water curing, but can be prevented by internal curing. Although the desiccation and resulting shrinkage of UHPC were effectively mitigated by the internal curing, a slow strength development was found when maintaining a high internal relative humidity.
Under water-curing conditions, the internally cured UHPCs showed 12–17% lower strength at 28 days compared with the reference sample. However, the results were 0–1% when exposed to dry air (relative humidity: 60%) between 7 and 28 days, showing accelerated external drying. The results show that the early-age shrinkage-related problem of UHPC can be fundamentally resolved, without a negative effect on strength, by controlling the drying period.
The study is published in: Cement and Concrete Research Volume 108, June 2018, Pages 20-30.
Formulating Adhesives and Sealants
This book teaches adhesive and sealant formulation in two steps. Each section first describes the application and chemical basis of the type of adhesive or sealant concerned. This is followed by formulation advice and - if possible - an analysis of existing recipes. This analysis includes a calculation of the important characteristic values of the formulations. All calculations based on recipes and formulations are worked through step by step and should therefore be intelligible to beginners, too.
You are currently not logged in
To leave a comment, please log in.
There was an error while sending your comment. Please try again.
Your comment was too long. There are a maximum of 2048 symbols allowed!