# Alkali-silica Reaction Elimination Potential of High-Performance Concrete Containing Glass Powder
## 3 Results
### Alkali-silica Reaction Process  
The specimens for ASR testing were prepared according to ASTM C1260 and T137 standards. A total of nine concrete mixtures were prepared for testing, of which eight were alternative with the use of different types of powdered glass and one was used as a reference mixture. Samples of size 25 mm \(\times\) 25 mm \(\times\) 285 mm were subjected to tests according to two standards, always in a set of three pieces. All the samples passed the experimental process in one piece, which is evident in Figure 1. Small cracks (up to 1 cm) appeared on one reference sample (mixture REF HPC), mainly coming from the edges of the sample. No changes in the surface structure were visible in the other samples. The measurements were recorded in three decimal places. All the results were graphed and divided according to the standards that were used. A summary of all the results is clearly shown in Figure 2a-d. Due to the large amount of measured data, for clarity, the figures were divided according to the glass replacement that was used, that is the individual glass substitutes were compared with each other according to the tests that were performed. The 50% and 100% replacements are combined into one figure (CWG, GPP, SGP, and SGJ), and each figure also contains a reference sample for comparison (REF). The ASTM C1260 standard specifies certain values according to which it is possible to assess whether the tested mixture is safe from the point of view of ASR, whether it is necessary to test it further, or whether it is dangerous from the point of view of ASR. In case the mixture is below the expansion value of 0.1% after 14 days, the standard indicates the harmless behavior of the concrete. After this basic period, which both standards indicate for testing, it is advisable to continue testing for at least another 14 days. If the expansion values do not exceed 0.1% after 28 days, it is still possible to declare the mixture as harmless. If the values are in the range of 0.1-0.2%, it is advisable to subject the mixture to further testing. However, if the expansion value at the age of 28 days is greater than 0.2%, the mixture may be at risk of a potential alkali-silica reaction. In this case, it would be advisable to switch to long-term precise testing of the mixture. The results of this research vary from harmless mixtures to those with potential risk of ASR. The reference sample exceeded the safe value of 0.1% after 14 days but was still within the 0.2% zone after 28 days. From this it can be concluded that further testing is necessary, which is planned in the next phase of this research. Although the reference mixture that was used in this work has been developed for several years, the risk of an alkali-silica reaction has never been verified, and therefore, this research is also being tested as a basis for improving the reference mixture. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Element img/L** & **SF** & **CWG** & **SGJ** & **SGP** & **GPP** & **REF HPC** & **CWG HPC 100** & **SGJ HPC 100** & **SGP HPC 100** & **GP HPC 100** \\ \hline Si & 24.0 & 14.8 & 8.2 & 48.7 & 14.7 & 3.0 & 2.5 & 2.3 & 3.6 & 5.2 \\ Na & 0.7 & 128.3 & 194.7 & 50.6 & 87.1 & 2.2 & 3.0 & 6.2 & 1.2 & 3.6 \\ K & 1.9 & 4.5 & 110.5 & 32.7 & 0.7 & 18.6 & 15.6 & 10.8 & 18.7 & 8.8 \\ Ca & 3.4 & 5.7 & 3.0 & 1.5 & 6.1 & 20.6 & 26.5 & 20.4 & 20.3 & 54.2 \\ Al & \(<\)0.8 & 3.0 & 7.9 & \(<\)0.8 & 27.9 & \(<\)0.8 & \(<\)0.8 & \(<\)0.8 & \(<\)0.8 & \(<\)0.8 \\ pH & 6.8 & 10.5 & 10.9 & 11.1 & 10.3 & 11.0 & 11.1 & 11.0 & 10.9 & 11.4 \\ Ecotoxicity & S & S & S & S & E & S & S & S & S \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical and ecotoxicological properties of GP and HPC leachates. S—safe, E—ecotoxic (10% leachate caused \(\geq\) 50% effect in at least one ecotoxicity test—water flea, algae, duckweed).