PSI - Issue 28

Chbani Hamza et al. / Procedia Structural Integrity 28 (2020) 430–439 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

437

- The point A: is called the coordinate breaking point: on the abscissa: X A = D max /2, in ordinate: Y � � ����D ��� � � � � � K is a correcting term depending on the cement dosage, the shape of the crushed or rolled aggregates, and the modulus of fineness of the sand. The aggregates available in the laboratory are of the normal crushed type, the cement dosage is 275 kg/m3 which gives a corrective term K=+5 Dreux and Festa (1998). Ks is an additional correction term given by equation (11). 15 6 s   FG K M (11) Hence : Y A =51.12 The OAB reference grading curve shall be plotted on the same graph as the grading curves of the component aggregates (Fig. 3). We then draw the dividing lines by joining the 95% point of the curve of the smallest aggregate to the 5% point of the curve of the next largest aggregate, and so on (Fig. 4),resulting in two dividing lines.

A

Fig. 4. Determination of aggregates proportions using granulometric curves The crossing point of the reference curve with the dividing lines allows read the absolute volume percentage of each aggregate: S0/4, G3/8, and G8/16. According to Fig. 4, we find the following results:  For sand: 30%.  For 3/8 gravel: 45%.  For 8/16 gravel: 25%. For one cubic meter of concrete :

1000 absolute V  

(12)

With