Diagnosis of the % of fines in the Alto Guadalentín region and its influences on the different applications.
In recent years, Explotaciones Mineras de Lorca, S.L. has found that depending on the quarry face from which the material is extracted to be treated and crushed to produce the aggregate it sells, the percentage of fine material that comes out is different, which has repercussions on its subsequent use.
The aggregates produced by Explotaciones Mineras de Lorca are mainly used for the production of concrete, and it can be seen that the amount of fines affects parameters such as workability. The amount of fines affects the porosity of the concrete and the total surface area of the fines affects both the self-compactability characteristics as well as the mechanical properties of the concrete. In general, if the concrete contains a lot of fines, its flowability decreases. On the other hand, if it has a small amount of fines, there is not enough mortar to cover the aggregates adequately. Thus, the amounts of fines affect the flowability, cohesion and water retention, which could lead to segregation and exudation of the concrete, with all the associated problems. For this reason, it is very important to properly determine the amount of fines to be used to make SCC when the amount of cement is a constant. The existence of excess fines in concrete leads to the need for aggregates which distort the properties of the concrete.
To this end, the company decided to carry out a study on the aggregates in its area of influence, in the Alto Guadalentín region, in order to check the level of fines in the different quarries and to verify the influence of these fines and the possible solutions that the company should implement in the future to avoid problems caused by its aggregates in the manufacture of fresh concrete by its customers.
It has been verified that the aggregates in the area have a high percentage of fines, around 15%, although the standard allows us that a percentage of fines between 15% and 18% is acceptable, the objective is to reduce this percentage. If we focus on Explotaciones Mineras de Lorca, it has been found that the percentage of fines is between 13% and 20%, depending on the quarry face from which the sample was taken.
As a conclusion to the study, the company considers that it will be necessary to carry out a final screening to regularise the dispersion found in the percentage of fines introduced by the quarry face. In return, this screening system will produce a waste that the company will have to assess. In this way, they will be able to regulate the fines content to an optimal level. In this way, they will be able to regulate the fines content and the waste obtained to an optimum level.
This project has been carried out in collaboration with the company Geproin EMP S.L. In addition, this project has been partly financed by the Instituto de Fomento de la Región de Murcia, within the 2019 call for aid to encourage the contracting of innovation services (innovation cheque) co-financed by the European Regional Development Fund (ERDF).
