# Effect of Metallic Waste Addition on the Physical and Mechanical Properties of Cement-Based Mortars
## 4 Conclusions  
This paper has explained the influence of the type and amount of two different types of metallic waste on the physical and mechanical properties of cement-based mortars. The main conclusions in this article are summarised as follows:  
* Regarding the mechanical performance of mortar specimens, it was concluded that the addition of metallic waste produced slight variations on their flexural and compressive strength. In addition, mechanical resistance of mortar specimens with metallic waste proportionally increased with the increase of the waste content.
* Additionally, it was found that specimens with shavings presented, on average, higher values of their mechanical properties than did specimens with fibres. This was attributed to the surface aspect of metallic waste, since shavings have a rough surface that facilitated the adherence between them and the mortar matrix, thus avoiding slipping on the shavings' edges, while fibres presented a smooth surface, which was more susceptible to failure by pull-out slipping.
* Furthermore, the results showed that the compressive elastic modulus increased with the amount of metallic waste added to the mortar, while in contrast, the dynamic elastic modulus obtained from ultrasonic tests decreased with the increase of metallic waste. This was associated with the increase on the mortar porosity due to the addition of metallic waste, which resulted in specimens with higher contents of metallic particles presenting higher ultrasonic pulse times and consequently lower values of dynamic moduli.
* Moreover, it was found that the elastic modulus measured by ultrasonic tests was on average higher than that measured by compressive tests. Besides, due to the random distribution of metallic waste inside the test specimens, there was no relationship between the static and dynamic elastic moduli, in contrast with conclusions obtained in previous works.
* Finally, based on a probability analysis of the obtained results, it was concluded that neither the type and amount of metallic waste, nor the curing time applied to the mortar specimens produced a significant variation on either the mechanical strength (flexural and compressive) or the elastic modulus of mortars measured by destructive and non-destructive methods.  
Considering that the metallic waste addition did not compromise the mechanical performance of the cement-based mortars, a continuation of this study, an exploratory study to evaluate the cracking damage self-monitoring properties of cement mortars by measuring the variation of their electrical resistance, is currently being developed.  
[PERSON] was responsible for all the research presented in this paper. He conceived the idea and designed the experiments, and his work was focused on the data interpretation and manuscript writing.  
Figure 12: Weibull probability-probability plots of the Modulus Influence Ratios (MIRs) data, for all specimens reinforced with (**a**) shavings and (**b**) fibres.  
[PERSON] and [PERSON] performed the experimental tests and were responsible of data collection and analysis. [PERSON] was responsible for the development of the experimental program. [PERSON] provided technical advice, and revised and improved the manuscript.  
The authors would like to acknowledge the help provided by [PERSON] from the Laboratory of Civil Engineering from the University Andres Bello. In addition, the authors want to thank [PERSON] from LabMAT for the technical support given and the company Sika S.A. Chile for the provision of the additive. Finally, the authors wish to express their gratitude to [PERSON] from the University of the Basque Country (UPV/EHU) for his help at the beginning of the experimental programme.  
The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.