# A Review on the Performance of Concrete Containing Non-Potable Water
## 5 Hardened Properties
### Chloride Penetration  
Two of the most important factors to evaluate the applicability of any WW materials in terms of durability are chloride ion penetration and carbonation. Studies regarding the effect of WW on the carbonation of concrete are very scarce. Therefore, we only focused on available data in the literature, namely studies on chloride ion penetration.  
Figure 19 shows the relative chloride ion penetrability (based on the charge passed, in Coulomb) of concrete made with treated [15; 27; 28; 38] and untreated [16; 24] WW. The results show that chloride ion penetration increases by increasing the incorporation ratio of untreated WW (up to 33%). Despite the fact that the evidence regarding the mentioned increment was not enough, it can be said that it happened because less hydration products will be formed with untreated WW, and relative to potable water, untreated WW has higher chloride ion content [16]. In general, the opposite conclusion can be seen in concrete  
Figure 17: Effect of different types of WW on the water absorp + tion of concrete relative to that of potable water concrete.  
made with treated WW. This mostly related to the fact that the sulphates and chlorides contents are specifically reduced in the treatment process of water to reduce the risk of concrete deterioration [16]. In addition, another study [10] reported that the low chloride ion penetration rate of treated WW concrete is related to the fact that the iron content of treated WW was lower than that of potable water.  
Apart from the chloride ion permeability based on the charge passed, the test can be directly made either using rapid or natural chloride ion penetration for a given time. For example, the study of [PERSON] et al. [10] investigated the effect of different types of WW on the chloride ion penetration of concrete samples immersed in a standard solution for 28 and 90 days (Figure 20). The results show that the chloride ion penetration resistance decreases in all types of WW (fertilize factory, textile factory, sugar factory and service station) despite the fact that the compressive strength of concrete was not significantly reduced. As mentioned before, there is not enough evidence on this phenomenon, but it can be related to the fact that some of the minerals (e.g., chloride content) may not significantly affect the strength of concrete but be effective in hindering chloride ion penetration.  
Generally, based on the studies [10; 15; 16; 24; 27; 38] in which 39 different concrete mixes were considered, the average chloride ion penetration resistance of concrete fell by 38%, 25%, 18% and 18% with the use of untreated WW, fertilizer factory WW, textile factory WW, sugar factory WW, and service station WW, respectively, and increased by 13% with the use of treated WW. Regarding treated WW, \"treated WW + bacterial solution\" increased chloride ion penetration up to 71%. However, this value was not considered in the conclusions because it can be considered a special case. This is because the bacterial solution microbially induces calcium carbonate precipitation in concrete by _bacillus cereus_ that leads to reducing the water absorption and chloride ion penetration rate [27].  
Figure 18: Relationship between compressive strength and water absorption.