Paper by PADILLA from ISCR 10th 2006 Brussels Belgium
This work describes the activities developed in Mexico to improve the selection criteria for stone aggregates which are used in surface layers for concrete pavements. The experience has shown that the current mechanical resistance requirements for stone aggregates often do not assure an adequate behavior. In other words, the selection criteria require more testing to improve the characterization of stone aggregates. The paper describes the mechanical characteristics of typical stone aggregates. We present and discuss results of skid resistance testing on concrete pavements that have been used during eleven years. These results showed the greater resistance and duration of surface layers formed by dense volcanic aggregates and the low resistance and low durability that limestone aggregates have due to vehicle loads and environmental conditions. In addition, we discuss the results of accelerated polish testing which are not included in the governmental specifications. These results show that none of the limestone aggregates tested fulfilled the new acceptance criteria. Finally, an experimentation program is proposed to obtain the necessary information to improve tests, specifications, and acceptance values for the mechanical resistance of the stone aggregates that are used in surface layers for concrete pavements.