Experimental research on assessment of concrete’s compressive strength of centrifugal concrete piles

Centrifugal concrete products are manufactured using specific technology that changes the concrete proportion during consolidation. The bleeding of water reduces the water-to-cement ratio and increases the compressive strength of concrete. This affects the strength of the concrete determined on conventional casted cylinders, cen trifuged hollow cylinders, and drilled cores from piles. This research determines the experimental conversion factor of 80 MPa concrete between casted cylinders and centrifuged hollow cylinders, which is 0.86. The factor between casted cylinders or centrifuged hollow cylinders and drilled cores (diameter of 57 mm and height of 57 mm) is 0.87 or 1.01, respectively. These coefficients can be used in production quality control. Practical verification of established factors was carried out on high-strength prestressed centrifugal piles. It shows that the experimental conversion factor gives more reliable and precise results in converting the strength of drilled cores than the factor recommended in actual national standards. Consequently, larger-scale research is needed to review the national standards or to compile guidelines for centrifugal concrete piles.