Highway Research Record

II. PAVEMENT ENGINEERING AND PAVING MATERIALS
2. FLEXIBLE PAVEMENT
NEW PROJECTS
Development of Ready to Use Mixes for Repair of Potholes

Date of Start: April 2004
Central Road Research Institute, New Delhi (R,I)

Scope & Objectives
(i) Development of Binders for ready to use mixes for repair of pot holes
(ii) Optimization of storable mixes.
(iii) Development of sealing methodology
(iv) Study of storage life in sealed conditions
(v) Characterization of ready to use mixes
(vi) Field studies on application of ready to use mixes.
(vii) Development of guidelines for road maintenance using ready to use mixes.

Methodology

(i) Development of suitable modified bitumen and bitumen emulsion to be used as binder
(ii) Design of optimum mix with sufficient workability
(iii) Study of storage time – density relationship to study shelf life of mix in sealed conditions
(iv) Field study in dry and wet conditions
(v) Preparation of application guidelines for highway profession (vi) Dissemination of know-how.

Conclusions

Three special binders have been developed for manufacture of readymade mixes for maintenance. The typical properties of binders are given in Table.

Properties           

Type of Binders

A

B

C

Softening Point,°C

45-50

40-45

35-40

Penetration, 0.1mm

100-150

150-200

>200

Elastic Recovery,  %

>75

>75

>75


Type A mix may be used at 35-50°C and Type B mix at 25-40°C, and Type C mix at 10-25°C, as these remain workable at these temperatures. Further work is in progress to study workability of mix for a longer period of storage. Studies have established that mix remain workable for 6 months in sealed conditions and can be used for repair of pot holes using only one labourer and even under wet conditions. The study reports that the mix from repaired pothole does not push off after placement.

Significance / Utilization Potential
The maintenance of roads in monsoon/post monsoon will be easy and convenient using ready to use patching mixes developed under the project.

Limitations
The conclusions and application guidelines would be finalized after field studies have been conducted.