PSI - Issue 63

Stanisław Majer et al. / Procedia Structural Integrity 63 (2024) 51–57

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region of its behaviour. Elastic modulus or Young's modulus is highly relevant to structural design by influencing, together with the thickness of components, the structural rigidity of the system. In the case of cement bound granular materials (CBGM) its value depends on the content of cement in the mix, and thus their compressive strength (Katsakou & Kolias, 2007; Zvonari ć et al., 2024). This material, which is used as a primary and secondary road base, potentially offers the possibility of utilizing many waste materials. (Crucho et al., 2022; Farhan et al., 2018; Stehlik et al., 2015; Yuan et al., 2011). Concrete and cement bound granular material is not an isotropic material having tensile strength in the range of 6 9% of its compressive strength. With decreasing strength, the linear expansion coefficient also decreases. This property is used to characterise bottom layers of road pavements, which are considered flexible when their compressive strength is lower than 5 MPa. Table 1 summarizes the selected schemes for performing the modulus of elasticity tests for cement-bound mixtures.

Table 1. Selected methods for determining the elastic modulus.

Standard/ References

Method

Equipment

Type of loading

Comments

(EN 13286-43, 2003; Zvonari ć et al., 2024)

The static compressive modulus, (E c )

Compression testing machine

Tests conducted to destroy the sample

(EN 12504-4:2021, 2021; Pasetto & Baldo, 2016)

Ultrasonic Test Equipment

The dynamic modulus (E D )

non-destructive test

2PB-TR 2BP-PR

Testing machine with strain control

(EN 12697-26, 2018)

(Buczy ń ski et al., 2020; EN 12697-26, 2018; Farhan et al., 2016)

Testing machine with strain control

IT-CY

1.2. Case study The research was conducted, on one of the investments being carried out in Poland (large-scale industrial tanks). During one of the implemented projects, the possibility of changing the designed structural solution emerged. The first option considered in the project was deep foundation on piles. However, FEM calculations showed that it was actually possible to use foundation slabs instead which significantly reduced the costs of constructing the foundations. These should be made of cement-bound mixes of Elastic modulus 400 MPa or higher. Thus, 0.55 m thick prestressed concrete slabs were designed for the planned structures. The slab was placed on 1.75 m thick concrete base layer. Considering the critical nature of the project, extensive preliminary site examinations and tests were carried out to specify a concrete mix of appropriate Elastic modulus value. In addition, it should not pose construction problems during placement. The cement-stabilized layer should be made from on-site materials. Before starting the mixture design, input data was