An experimental study on the optimal compositions of ordinary concrete based on corrected dune sand—Case of granular range of 25 mm

Our study aims to solve the fundamental problem of concrete formulation in arid areas. The obtained results through the use of dune sand showed that most of previous studies in this domain did not meet the requirements- in terms of mechanical strength of concrete- and that is due to the sand granularity. The latter was mainly due to the absence of coarse sand grains. For this purpose, three (03) siliceous dune sand classes were used, with a maximum grain size of 2.00 mm and a modulus of fineness ranging from 1.55 to 1.74. These dune sands were corrected by two classes of Koussane siliceous-limestone crushed sands of 0/4 mm, with a fineness modulus of 3.02 and 3.4. It should be noted that the rates of correction by quarry sands are 20 %, 40 %, 60 %, 80 % including dune and crushed sands without correction (0 %, 100 %). A large experimental plan of 276 concrete tests was adopted on 15 cm cubic specimens. It included most of the expected possibilities using coarse aggregates with maximum dimension of 25 mm. The test results provided the mechanical strength obtained for the concrete that contains sand-dunes corrected at a rate of 60 %, 40 % and 20 %. The value of the mechanical strength in compression was 48 MPa, which was higher than all the values obtained using dune sand or crushed sand without correction. That said, the use of corrected sand was- financially speaking- cost efficient.