# Automated Control of the Fresh State of Industrial Concrete Behaviour by Rheometer Test Adjustment
###### Abstract
[PERSON] and [PERSON] [11] showed that all the rheometers were found to rank the mixtures in the same order for both the yield stress and plastic viscosity; the differences in the absolute values can be attributed to several issues, such as the slip at the interface of the device wall with the concrete or the confinement of concrete between the moving parts of the rheometers. that are highly sensitive to the operator. Moreover, the devices used to carry out these tests prevent their automatization (the Abrams cone, J-ring, L-box, etc.). Nowadays, several new concretes or once-off applications require the characterisation of certain fresh parameters that the traditional industrial test (the Abrams cone) cannot measure, such as the open time, fluidity variation over time, or viscosity. This is the case with highly fluid concretes or SCC, which require several industrial tests (slump flow, L-box, J-ring, etc.) [14; 15] that are too time-consuming to be performed on all concrete batches. The same issue exists in the precast industry with 3D-printing concrete [16], or the use of concrete with recycled concrete that absorbs free water from the mixture over time, thereby rapidly changing the fresh behaviour of the concrete [17]. In these recycled concretes, the duration of the mixing procedure and transportation can significantly affect the free water, and therefore the fresh behaviour of the concrete [15]. The same can occur when other by-products are used, such as wood ash, coal bottom ash, and filler from natural stone. The increased use of highly flowable mixtures for the rapid production of flat elements, such as floors or slabs, also requires this type of fresh control. All these situations require a precise assessment of the concrete fluidity at the production plant occasionally over time, along with certain other premises. In the current digital society, modern quality control tests must provide information for the storage and analysis of concrete performance. Fresh-behaviour control should be fully automated to minimise operator input and allow decision-making. The employment of rheometers permits the automatization and digitalization of all fresh state measurements. Fresh behaviour, throughout scientific parameters, can be assessed and data can be evaluated by experts to take actions (modify mix proportioning, reduce mixing time, etc.) that will improve concrete performance. This study aims to promote the use of a rheometer to obtain reliable and automated information regarding the fresh state of concrete. The use of rheology is demonstrated to encompass precision, repeatability, speed, and the possibility of controlling the mixtures over time, thereby helping engineers detect problems during casting and understand the fresh behaviour of mixtures (as data can be stored automatically). These issues are essential in several specific concrete applications, such as 3D printing [18], the precast industry [19], recycled aggregates [20], and visible and ornamental concrete. Furthermore, it can improve the control of general-purpose concrete plants. One of the main issues with rheometers is that there are no standard tests that can be applied to all concrete types. Rheological tests must be adjusted according to the concrete type, fluidity, aggregate type used, and admixtures. The main objective of this study is to promote the automation of rheological tests for the quality control of fresh concrete performance in the concrete industry. Accordingly, the development and adjustment of a device (rheometer prototype) is presented, which enables users to modify testing parameters, such as the impeller type, speed range, and test type. Once the device is developed, it is necessary to create a protocol to select the correct configuration of the rheometer, such as the impeller type and the most suitable testing procedure (time-speed profile). Once these issues are defined, all concrete batches produced can be controlled, and homogeneous quality is guaranteed.