Background:

The Mexican Federal Government has allocated a great deal of investment to the maintenance of pavements across the existing road network (in 2010 and 2011, this investment amounted to €7,860M and €7,894M respectively). During the 1990s, a pavement system was introduced in Mexico involving the incorporation of Portland cement using a mechanical process (grader) in order to improve the mechanical properties of the lower layers (base and subbase), thereby increasing their strength. However, homogenization of the stabilized base has never been achieved using this construction process. Currently, a process is being employed that involves reclaiming part of the existing pavement and incorporating Portland cement directly in situ using automated equipment, thereby allowing homogeneous application in the lower layers.

Methods:

In order to achieve this goal, comprehensive monitoring and data analysis were performed, based on granulometry, base compressive strength detail analysis, a height weight deflectometer (HWD) as a key tool for in situ evaluation (mainly in terms of base deflection and moduli).

Results:

There were tested 79 samples; the dosages of the mixture were between 180.6 and 201.6 kg of Portland cement according to the sand and gravel found on the field during recovery of the pavement. We observe that the samples are not homogeneous, given the differences in the size and number of particles that they comprise. Additionally, we observe that many of the grading curves lie outside the quality range. 96.4% of cores whose unconfined compressive strength was measured after 14 days comply with the minimum acceptable resistance of 114 kg/cm2. According to the samples taken to measure deflection the quality of the pavement structure, were improved with the new technology of construction of the stabilized base.

Conclusion:

Stabilization via in situ recycling with cement is an excellent recycling technique. It improves existing material without producing waste and limits the transportation of new products. This technique has a promising future.

        · resumen en Español | Portugués     · texto en Inglés     · Inglés ( pdf )