PERFORMANCE RESULTS OF SOIL STABILIZATION PROGRAMS IN LATIN AMERICA

In recent years, a growing number of countries have tested and begun using organic soil stabilizers for stabilization of soils in the base, sub-base, and sub-grade paved roads; or in the wear layer of secondary or rural roads. Road engineers in various parts of the world measure performance parameters after road construction and stabilization principally using the Dynamic Cone Penetrometer. The DCP penetration values of a conical probe vs. the number of hits of an 8-kg hammer have been correlated with CBR% data by many investigators. This simple, versatile and inexpensive device reliably profiles resistance throughout all layers of a road structure while providing objective measurement of the changes in soil mechanics and resistance properties after stabilization. While lab methods of CBR measurement are common in establishing soil load bearing levels, they are not useful for in situ road evaluations, as the act of removing the stabilized road soil samples for lab testing destroys the structure to be measured. This paper will discuss the soil properties effected by organic soil stabilizers, good engineering practices necessary for successful applications and experiences in actual road stabilization in Latin American countries as Brazil, El Salvador, Paraguay, and Honduras. Laboratory study results from BYU and national labs in Chile, Ecuador, Peru, Mexico, and Brazil have also evidenced improvements of soil properties through stabilization. Specific projects in actual road constructions on primary and secondary road surfaces, accompanied by DCP measurements, demonstrate improvement of soil mechanical properties and the benefits of soil stabilization, but also the utility of DCP usage in portraying resistance by road transverse structure level. Results of pavement projects in sections of Brazil and Paraguay will be presented. Soil stabilization is seen to provide important cost savings of up to 30% in the construction of primary, paved roadway by upgrading available and local soils and reducing importation requirements of expensive components. It greatly reduces the cost of maintenance and repair of secondary, rural, forest and plantation roads through reduction/elimination of rutting, wash boarding, deformation, potholes and dust due to increasedcohesion of the soil and consequently the CBR. Savings up to 75% are documented.