The role of geology on the radioactive attenuation using high density rock aggregates from Saudi Arabia

الملخص EN

Gamma ray and neutrons are highly penetrating and its attenuation is usually done by expensive manufactured materials.

In this study, heavy weight basic minerals (hematite, barite, magnesite, magnetite, chromite, and goethite) and one heavy weight basic rock (peridotite) from seven different sites in the western part of Saudi Arabia were used as concrete aggregate and was effective as gamma and neutron radiation shielding.

A total number of 48 Portland Cement Concrete mixes were prepared and tested.

Their compressive strength ranges from 16 MPa for hematite to 36 MPa for chromite, and due to its lowest strength value hematite will not be used as coarse aggregate.

On the other hand, the tensile strength varies from 2.3 MPa (magnetite) to 4.1 MPa (chromite).

The gamma (Ug) and neutron (Un) attenuation were taken as a measure for the concrete shielding that was tested using a total of 72 cylindrical plates.

The concrete attenuation ability depends on the rock type or mineral, their physical and mechanical properties, and degree of weathering.

The Ug values were found to range from 18 to 27%.

The chromite, magnesite, and magnetite concrete gave superior gamma attenuation coefficient over the ordinary basalt concrete.

The goethite concrete shield is more effective for both gamma and neutron attenuation than all other tested materials.

Simple relationships were deduced to determine the Ug values from very simple parameter such as the aggregate specific gravity, density, soundness, and strength.

Similar relationships were also derived between Ug values and the crystallized water in goethite.

Significant correlations were found for both cases.