After sample collection, the raw material is brought to an on-site laboratory where its strength and petrography (upon others) are investigated.
The excavated material strength is an important parameter in the process of selecting adequate raw material. Experience showed that aggregate strength should be at least twice higher than that requested for the concrete.
Aggregate strength can only be measured through the Los Angeles test. This method is time consuming and requires expensive infrastructures. Thus, the aggregate strength is derived from the point load and the breakability tests obtained from the raw material. Results from the breakability method correlate with those of the Los Angeles test.
The aggregate standards are based whenever possible on the SN 670'102 (EN 12620). In
addition, aggregates may fulfill other more extensive requirements (grains shape, fine material, etc...).
Another central parameter for the selection of raw material selection is its petrography. The actual standards are not suitable to evaluate neither the petrography of the raw material nor that of the derived aggregates.
B+ G developed his own directives for evaluating the petrography of excavated material and aggregates based on its 20 years experience. This method is widely accepted as a standard.
The test method developped by B+ G can be applied to a wide variety of materials such as surface samples as well as core samples.
B+ G advises you competently on the different reutilization possibilities of your raw material.
Since 2021 B+ G supports a consortium for the tender of the material management lot. Based on our experience, the raw material is continuously tested in the construction site's own laboratory.
Concrete tests with sulphate-containing aggregates (produced from tunnel excavation) and special binders were carried out in the Modane intermediate attack on 7 April 2016.
Among other things, the sulphate resistance is to be investigated.
The new Spitallam dam in the Bernese Oberland will require around 200,000m3 of concrete. The mass concrete consists of a maximum grain size of 125mm! A gravel plant was built for the production of the aggregates. B+ G supports the client KWO in the quality of raw materials, aggregates and concrete.