Abstract:
Tensile strength is important for plain concrete structures such as dam under earthquake
excitations. Other structures for example pavement slabs and airfield runways, which are
designed based on bending strength, are subjected to tensile stresses. Therefore, in the
design of these structures, tensile strength is more important than compressive strength.
The relationship of tensile strength with the compressive strength for different range of
concrete strength proposed by various authors and country standards indicate diverse and
wide variations in recommendations to predict the concrete tensile strength. Predicting the
tensile strength of concrete from its compressive strength has been under scrutiny for a long
time. Many researchers have investigated its prediction accuracy, i.e., how well it correlates
with or predicts test data.
The aim of this study is to evaluate the empirical formula used in EBCS-2 1995 to calculate
the tensile strength of concrete. To achieve this concrete mix design was provided to attain
the target compressive strengths of 25, 30 and 35 Mpa by following the specification
provided in the ACI manual. For each target strength three compressive strength test, three
center point loading test and three splitting tensile test for 7 and 28 days were conducted.
Therefore, the total number of sample size for the experiment was 36 cylindrical samples and
18 beam samples. After the experimental study the following conclusion has been made.
The ACI code provides adequate relation in the prediction of splitting tensile strength .while
EBCS-2 1995 underestimate the tensile strength.
In the case predicting the flexural strength of plain concrete EBCS-2 1995 gives the closer
value to actual flexural strength at latter age. But at early age ACI gives the closest value to
actual strength. The empirical formula used in EBCS-2 1995 to calculate the tensile strength
of a concrete need further study.
