# Durability Assessment of Eco-Friendly Bricks Containing
## 5 Discussion of Results from the Tests
### Mercury Intrusion Porosimetry (MIP)  
Figures 10 and 11 show plots of the cumulative distribution and log-differential distribution of the pore sizes, respectively, for the samples subjected to F-T cycles (F-T) and those not subjected to F-T cycles (NO F-T).  
Figure 10: Cumulative intrusion distribution of pore sizes for freeze–thaw and non-freeze–thaw samples.  
Figure 9: Plots showing mass changes and corresponding F-T cycles.  
As observed in Figure 10 for both exposures (F-T and NO F-T), the pores with diameters greater than 3 \(\upmu\)m were about 37%. Furthermore, the cumulative curves gradually became flat at pore diameters of about 0.1 \(\upmu\)m, so we can safely conclude that, regardless of the TRW content, all of the bricks had about 63% of pores with diameters less than 3 \(\upmu\)m. Hence, the average cumulative intrusion volume of 0.093 mL/g at 3 \(\upmu\)m represents the total pore volume of the sample. However, for the samples exposed to F-T cycles, the PV values obtained were 0.1309 mL/g, 0.1747 mL/g, and 0.2035 mL/g for the 0, 5, and 10% TRW samples, respectively. Referring to Equation (4) and computing Fc with the obtained PV values, the brick samples that had 0% TRW fell under the durable region, the brick samples containing 5% TRW fell within the uncertain region, and the samples with 10% TRW fell in the non-durable region. A similar trend was observed for the samples not exposed to F-T cycles (NO F-T). PV values of 0.1433 mL/g, 0.2 mL/g, and 0.2014 mL/g were obtained, respectively, and the brick samples that had 0% TRW again fell under the durable region. The brick samples containing 5% and 10% TRW fell within the uncertain and non-durable regions, respectively. However, it was observed that the samples with 5 and 10% TRW (NO F-T) and 10% TRW (F-T) had similar pore size distribution, with high mercury intrusion, while the samples with 5% TRW (F-T) had a dissimilar pore size distribution, highlighting a lower volume of mercury intrusion. It can be concluded that the size of the pores larger than 3 \(\upmu\)m in diameter contributed beneficially to the low mercury intrusion within the 5% F-T bricks [55; 62], even though the 5% TRW (F-T) samples had abraded spots after the freeze-thaw cycles.  
The bimodal trend observed in Figure 11 illustrates that two distinct pore sizes were present in the bricks, irrespective of the exposure conditions: macro- and micropores. The amount of TRW played a significant role in forming these pores, because the presence of the rubber created additional pores within the brick's matrix, leading to a higher intrusion volume (pink and green curves for 10% TRW F-T and 10% TRW NO F-T, respectively). For the 0% TRW sample (yellow curve for F-T), a peak intrusion volume of 0.095 mL/g was recorded within the micropores section, after which the curve flattened. This indicates that, at 0% TRW, the intrusion was very low due to the sample's micropore sizes, which translated to durability irrespective of the effect from the F-T cycles. For the other samples (5% and 10%), the intrusion volumes were higher when compared to the 0% TRW content, resulting in the bricks being classed as uncertain and non-durable.