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C OLLECTION TECHNIQUE C I M B É TO N

T 30
English version

COMPARATIVE STUDY IN ROAD ENGINEERING SOIL TREATMENT VS UNBOUND GRANULAR MATERIALS

Graphic method for environmental and economic comparison

SOIL TREATMENT VS UNBOUND GRANULAR MATERIALS
TREATED SOIL PLACEMENT IMPACT AGGREGATES PLACEMENT IMPACT

4

8

3

7

Treated soil (cm)

35 60 50 40 4 5 6 30 20 10 7 8 9 Binderproportion (%)

90 80 1 2 10 20 30 40 50 60 70 80 90 100 110 120 130 140

70 3

Aggregates (cm) 50 10 20 30 40 50 60 70 80 90 180 160 140 120 100 80 60 40 20 Equivalent distance (km)

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BINDER IMPACT PRODUCTION + TRANSPORT

1
DRY DENSITY OF MATERIAL TO BE TREATED

5
MATERIALS TRANSPORT IMPACT

6
AGGREGATES EXTRACTION AND PRODUCTION IMPACT

© J. ABDO - CIMBÉTON

COMPARATIVESTUDY IN ROAD ENGINEERING SOIL TREATMENT VS UNBOUND GRANULAR MATERIALS

Graphic method for environmental and economic comparison

This document was written by Joseph ABDO, road manager - CIMBÉTON, French cement association, and approved by the following Working Group: Ludovic CASABIEL David CUINET Frédéric DIDIER Patrick DUBOIS Antoine GARRIDO Jean-Chrisrophe REDON CIMENTS VICAT LAFARGECIMENTS HOLCIM CIMENTS CIMENTS CALCIA CIMENTS CALCIA LAFARGE CIMENTS

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Foreword

commercial or logistical use, prior design and building of a specific road transport platform of minimum bearing capacity is necessary, allowing construction of the actual pavement structure.

● To build roads, motorways, airport areas or any other area development for industrial,

Building the specificplatform, which relates to road earthworks, consists in carrying out levelling works (cuttings and embankments) and building a structural layer referred to as « capping layer ». Cutting, embankment and capping layer works may be performed using one of the two following techniques: • The technique of unbound granular materials, which consists in using granular materials from gravel pits or quarries,• The technique of in situ Soil treatment with hydraulic binders, which consists in adding value to natural soils (existing on the construction site) by mixing them with hydraulic binder and water. These two techniques have advantages and drawbacks, both at economic and environmental level. The technique of unbound granular materials, that uses granular materials whose extraction and productionhave low economic and environmental impact, may be hindered by the impact generated by: - transport of aggregates (a heavy bulk product), when the distance between the quarry and the construction site exceeds a certain threshold. - transport of surplus soil between the construction site and the tip. The technique of in situ Soil treatment with hydraulic binders requires the use of a hydraulic binderwhose production has a non-negligible economic and environmental impact. However, this binder is used in low proportion and the quantities produced and transported are small compared to the quantities of unbound granular materials. Therefore, depending on the context of each project (distance between quarry and construction site, construction site and tip, binder proportion, distance betweenbinder plant and construction site), one of these two techniques may prove to be economically and/or environmentally more valuable. This manual, entitled « Comparative study in road engineering - Soil treatment vs Unbound granular materials » provides a graphical method that helps determine and compare economic or environmental indicators (Energy and CO2).

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It has a dual advantage: - itallows users to choose the values of parameters at each stage of the study, depending on the local data of their projects, - it allows users to quickly and visually assess and compare, in a cumulative progression, which of the two techniques, Soil Treatment or Unbound granular materials, is most appropriate, economically and/or environmentally. It takes into account the production impact (binder,...
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