Sorel Gael Dzaba Dzoualou¹, Louis Ahouet^{1, 2,}, Sylvain Ndinga Okina^{1, 3}, Mang Egrik P. W. O. Nkembo¹

This work evaluates the effect of adding limestone (corrector) to lateritic gravelly on the granulometric fractions of the mixtures in the process of modifying the mechanical properties. The lateritic gravelly - limestone couple does not obey the law of mixtures. The optimal mixture is obtained by adding 30 % by weight of the corrector to obtain a mixture with unmeasurable clay, silt (4.25 %) and sand (19.47 %) contents. The results obtained show that from 15-30% by weight of the corrector, the compressive strength, elastic modulus, CBR and maximum dry density increase and the use properties are improved. From 30-40% by weight of the corrector with sand fraction SF (19.47-21.09%) in the mixture, the mechanical properties decrease. The addition of the corrector (15-40%) decreases the clay (5.18-1.68%) and silt (14.09-0.67) fractions, while the sand fraction (12.93-21.09%) increases by 63.11%. The increase of the sand fraction by 50.58% decreases the plasticity index by 77.16%. For a sand fraction SF (50.58-63.11%), the plasticity index is not measurable and the sand equivalent SE (32.5-35%) of the mixture increases by 7.69%. Increasing the sand fraction causes the compaction curves (Proctor) to flatten and the optimum moisture content to decrease. There is a negative correlation between compressive strength and strain at failure. Mixes containing 15-25% and 30-40% of the corrector can be used as a base layer for T1 < (5.10⁵) and T1-T2 (5.10⁵ - 1.5.10⁶) traffic respectively, in terms of the cumulative number of passes of a 13T equivalent axle.

lateritic gravelly, geotechnical, particle size fraction, mechanical properties of soil, optimization of mixture