Technical Guide - Treatment of soils with lime and/or hydrolic binders : Application to the construction of pavement base layers

This  guide  codifies  the  technique  of  soil  treatment  with  hydraulicbinders, in some cases in combination with lime, for the constructionof   pavement   base   layers.   It   supplements   the   “Guide   techniqueTraitement   des   sols   à   la   chaux   et/ou   aux   liants   hydrauliques   -Terrassement et couche de forme” (GTS – Sétra/LCPC, 2000) and theapplicable standards. The first part of the document explains the types of soils involved andthe  specifications  for  uniformity.  It  details  the  content  of  studies  andhow they change in nature from geological surveys to laboratory tests. The  second  part  describes  the  design  of  treated  soil  pavement  baselayers.  It  states  the  traffic  classes  for  which  these  materials  may  beused  and  explains,  with  regard  to  the  design  method,  the  parametersthat   are   specific   to   treated   soils,   in   particular   the   mechanicalcharacteristics  measured  in  a  laboratory  weighted  on  the  basis  of  theconditions  at  the  site  and  the  state  of  the  interface.  It  ends  withexamples of design using fine treated soils. The third part explains how works and the monitoring of the materialsshould be performed, the ways the materials should be prepared at theconstruction  site,  defines  the  levels  of  quality  on  the  basis  of  theequipment used (in-situ and in a plant), the conditions of transport andlaying,  the  surface  protection  to  be  applied  on  the  basis  of  forecaststresses and the quality control procedures.  This document ends with a series of annexes dealing with the soil datasheet  and  the  specifications  of  soils  used  in  pavement  base  layers,some economic factors and, finally, a summary of the survey that wascarried out on treated soil structures constructed in France.

Contents 1 - Introduction .................................................................................................................................7 2 - Studies ........................................................................................................................................ 10 2.1 - The types of soil covered by the guide ...............................................................................10 2.2 - The progressive nature of studies .......................................................................................11 2.3 - Characterization of the deposit ...........................................................................................12 2.3.1 -Minimum features of the geotechnical survey ................................................................12 2.3.2 -Evaluation of the uniformity of the deposit..................................................................... 12 2.3.3 -The mechanical strength criterion of the granular fraction .......................................... 14 2.4 - Mix design studies................................................................................................................. 15 2.4.1 -Objectives of the mix design study ................................................................................... 15 2.4.2 -Need for pretreatment with lime ...................................................................................... 15 2.4.3 -Choice of binder for the mix design study ....................................................................... 15 2.4.4 -Soil specimen used for the study ...................................................................................... 15 2.4.5 -Complete study .................................................................................................................... 16 2.4.6 -Limited study ........................................................................................................................ 17 2.4.7 -Identification of the constituents........................................................................................ 17 2.4.8 -Reference tests for compaction .......................................................................................... 17 2.4.9 -Study of the immediate stability .......................................................................................... 17 2.4.10 -Specimens ............................................................................................................................. 18 2.4.11 -Conservation.......................................................................................................................... 20 2.4.12 -Performance .......................................................................................................................... 21 2.4.13 -Sensitivity study of mechanical performance......................................................................21 3 - Design ............................................................................................................................................. 22 3.1 - Traffic data................................................................................................................................... 23 3.1.1 -The Ti traffic classes.................................................................................................................. 23 3.1.2 -The TCi cumulative traffic classes............................................................................................ 23 3.1.3 -Aggressiveness of traffic ........................................................................................................... 24 3.2 - Classes of subgrade ..................................................................................................................... 25 3.3 - Design parameters........................................................................................................................ 25 3.3.1 -Materials........................................................................................................................................ 25 3.3.2 -The interface conditions.............................................................................................................. 29 3.4 - Pavement design ........................................................................................................................... 29 3.4.1 -Application .................................................................................................................................... 29 3.4.2 -Minimum qualities .......................................................................................................................29 3.4.3 -Types of structures........................................................................................................................ 30 3.4.4 -Surfacing layers ............................................................................................................................ 30 3.4.5 -Constructional measures ............................................................................................................ 30 3.5 - Verification of frost design ........................................................................................................... 31 3.6 - Examples of design ....................................................................................................................... 31 3.6.1 -First example (Table 26) ............................................................................................................ 31 3.6.2 -Second example (Table 27)....................................................................................................... 35 4 - Implementation .............................................................................................................................38 4.1 - Foreword .................................................................................................................................... 38 4.2 - Preparation of materials .......................................................................................................... 39 4.2.1 -Sorting of the material ........................................................................................................... 39 4.2.2 -Removing aggregate above a certain size ............................................................................39 4.2.3 -Pretreatment with lime .......................................................................................................... 39 4.2.4 -Creation of stockpiles and rehandling..................................................................................40 4.2.5 -Moistening .............................................................................................................................. 40 4.2.6 -Validity of the selected methods.......................................................................................... 42 4.3 - Manufacture ............................................................................................................................ 42 4.3.1 -The level of quality of the treatment equipment for pavement base layers ................ 43 4.3.2 -Treatment in situ .................................................................................................................. 47 4.3.3 -Treatment in a plant ............................................................................................................ 48 4.4 - Transport and laying.............................................................................................................. 49 4.4.1 -Transport of mixtures .......................................................................................................... 49 4.4.2 -Laying ....................................................................................................................................49 4.5 - Surface protection ..............................................Erreur ! Signet non défini. 4.6 - Surface protection ................................................................................................................. 51 4.6.1 -Characteristics related to the nature of the treated soils................................................. 51 4.6.2 -Mechanical stresses ............................................................................................................. 51 4.6.3 -Climatic stresses .................................................................................................................. 51 4.6.4 -The different types of surface protection ........................................................................ 52 4.6.5 -Choice of the type of surface protection ......................................................................... 53 4.7 - Quality control ...................................................................................................................... 56 5 - Abbreviations - symbols - definitions ................................................................................... 65 6 - Bibliography ............................................................................................................................. 68 7 - Annexes.................................................................................................................................... 75 7.1 - Annex A ................................................................................................................................ 75 7.2 - Annex B ................................................................................................................................ 76 Specifications for soils used in pavement base layers............................................................. 76 Economic factors.......................................................................................................................... 77 7.3 - Annex C ................................................................................................................................ 78 The contribution of each item to the cost of the treated soil in question..............................78 The contribution of each piece of machinery to the cost of the treated soil i