Optimization of Rigid Pavement

Abstract

Abstract: The construction of national highways nowadays is preferred by using rigid pavements as they are durable, have the high flexural strength, can withstand different heavy axle loads, higher design span and moreover they can sustain adverse environmental conditions more efficiently with better ease. Considering their remarkable qualities, the national highways should be constructed by providing the tied shoulders and dowel bars in the transverse joints because they can better resist the fatigue accumulations on the slab with minimum safe thickness which ultimately leads to reduction in the cost of making the road efficiently. In this chapter, for the two different CBR conditions (CBR-9 & CBR-10) and three concrete mix design grades namely (M40, M45, M50) along with different shoulders and dowel bars conditions, the trial methods were carried on the IRC58 Software for bottom-up cracking fatigue analysis for single and tandem axle for day-time (6 hour) traffic and positive temperature differential and top-down cracking fatigue analysis for single, tandem and tridem axle for day-time (6 hour) traffic and negative temperature differential for evaluating the flexural stresses and cumulative fatigue damage values for the slab having dimensions of (3.5m x 4.5m). For determining the safe design, different trails on the thickness parameter of the slab were being adopted so as to get the cumulative fatigue values of BUC and TDC for single, tandem and tridem axles less than one. The results obtained showed that for which grade and CBR condition, the values of flexural stresses and cumulative fatigue damage determined is maximum. It was concluded that the rigid pavements should be constructed by using higher grades like M45 and M50 as the fatigue stresses and cumulative fatigue damage values due to variable single, tandem and tridem axle load repetitions obtained are less as compared to M40 grade. Keywords: California Bearing Ratio (CBR); Bottom Up Cracking (BUC); Top Down Cracking (TDC); Mix Design Grade Value (M), Indian Road Congress (IRC); Flexural Stresses; Cumulative Fatigue Damage(CFD)