Analysis and design of concrete pavements

Module II : Analysis and design of concrete pavements

Lecture 1 : Pavement Materials

1.3. INNOVATIVE APPLICATIONS

Innovative applications may be construction method based or design principle based. Some of the relevant issues are discussed in the following.

1.3.1 Construction Method Based

A mixture of aggregate and binding material, at varied proportions, constitute various specifications for road construction, for example, bituminous concrete, built-up spray grout, wet mix macadam, lean cement concrete etc. Discussion on all these standard specifications have been skipped here, rather, some specific mixes and their construction methods are discussed.

Emulsified bituminous mix

Cold emulsified bituminous mix (EBM) is gaining more and more acceptance for its environmental friendliness and less hazardous construction process. A relative comparison between the EBM and hot bituminous mix (HBM) has been presented in Table 4. It may be noted that though the rate of strength gain in EBM is slower (refer Figure 7), the final strength of EBM is comparable to that of HBM.

Table 4. Comparison of hot bituminous mix (HBM) and emulsified bituminous mix (EBM)

Property	HBM	EBM
Heating	Strong heating required, oxidative hardening occurs	No heating required, so no oxidative hardening
Setting time	Low	High
Applicability	Clear weather with high ambient temperatures	All weather (wet surfaces, rainy seasons, cold)
Convenience	Relatively difficult construction than EBM	Relatively easy construction
Energy	Relatively higher requirement	Relatively lower requirement
Uniqueness	Modifiers needed	Inherent anti-stripping agents
Economy	Less costly	More costly
Safety	Hazards from fuming, fire and environmental pollution	Free from such hazards

Figure - 7 Strength gain of EBM versus HBM