International Journal of Engineering and Technical Research (IJETR) ISSN: 2321-0869 (O) 2454-4698 (P), Volume-3, Issue-10, October 2015 81 www.erpublication.org Abstract— This work presents structural analysis of Plastic Cell filled Concrete Block Pavement (PCCBP) called flexible concrete pavement using BACKGA (a linear elastic theory based backcalculation code). Layer moduli of different layers of PCCBP have been calculated from the surface deflection data obtained through Falling Weight Deflectometer (FWD). The layer moduli obtain as outputs from BACKGA is given as inputs to both ABAQUS and KENLAYER and the resulted deflections are compared with that of the experimental values. It has been observed that peak deflections were predicted well by KENLAYER, in contrast to FE (ABAQUS) results which under predicts by ~ 38%, 36%, 33%, 30% and 28% for 50 mm, 80 mm, 100 mm, 120 mm and 150 mm PCCBP thicknesses respectively. 50 mm thick PCCBP layer result in sufficiently high layer modulus (>1900 MPa), 90% increase in layer modulus (approximately linear) was observed for 200% increase in thickness. Index Terms— Stone dust, low volume roads; Plastic Cell filled Concrete Block Pavement (PCCBP); Flexible concrete pavement; Falling Weight Deflectometer (FWD); BACKGA, KENLAYER, ABAQUS I. INTRODUCTION Designing sustainable rural roads with reasonable riding quality and low life cycle cost has always been one of the major challenges for pavement engineers and researchers. The research effort in this direction has become far-reaching pertinent in India as the share of low volume (< one million Equivalent Single Axle Loads (ESAL) in a life cycle as per [1, 6] rural road is about 80% of the total road length [26]. Whilst conventional flexible pavement with a thin cover of premix bituminous carpet is normally adopted for rural roads, frequent maintenance are required (to maintain both functional and structural efficiencies) due to damages caused by poor drainage conditions, overloaded vehicular traffic, iron wheeled bullock carts etc.As a result such pavement incurs huge maintenance cost. To offset such expensive maintenance cost, concrete pavements are increasingly used in rural road connectivity in India because of their durability. However it not only involves high initial cost but can also fail due to various reasons like day and night variations in warping stresses, seasonal changes in the modulus of sub-grade reaction etc. [29]. Although pre-cast concrete block pavement [8, 9, 27] provides more flexible response Yendrembam Arunkumar Singh, Department of Civil Engineering Manipur Institute of Technology, Takyelpat Imphal - 795004, Manipur, India, Mobile No. 9612996443. Konjengbam Darunkumar Singh, Department of Civil Engineering, Indian Institute of Technology, Guwahati, Guwahati-781039, Assam, India, Mobile No. 9435731483. Teiborlang Lyngdoh Ryntathiang, Department of Civil Engineering, Indian Institute of Technology, Guwahati, Guwahati-781039, Assam, India, Mobile No. 9435302113. (depending upon the dilantancy of the jointing sand) as compared to the normal concrete pavement mentioned above, there is a tendency for block movements under braking or accelerating force of the vehicular traffic and the interlocking caused by the jointing sand needs frequent maintenance which may not be practical for rural roads. As an alternative, for better structural performance and low maintenance, a new pavement technology called Plastic Cell Filled Concrete Block Pavement (PCCBP) was developed in South Africa [30, 31]. In PCCBP, diamond shaped heat welded plastic cells are used to encase concrete blocks. It may be noted that this type of plastic cell formwork has been successfully used for canal lining, reinforced earth treatment etc., [30]. The cells are tensioned and spread across the foundation layer and concrete is filled and compacted into the cells. Upon compaction the cell walls get deformed resulting in interlocking of adjacent individual concrete blocks. Flexibility is induced into cement bound (rigid) surface and [30] termed these pavements as Flexible Concrete Pavements. The PCCBP has good load spreading capacity with negligible maintenance during its life. Although construction of PCCBP can be mechanized, significant amount of hand labour may be utilized making it labour intensitive with possibilities of generating employment opportunities for the rural inhabitants. In India, limited studies on this PCCBP technology have been reported by [20, 23, 24, 25, 27] on the cost effectiveness and feasibility for rural roads. Albeit their studies were confined to selected (~100 mm) PCCBP thicknesses, it was observed that PCCBP can provide sufficiently high elastic modulus with low initial and maintenance cost. Recently authors have attempted to study the effect of PCCBP thickness on the structural performance of pavement considering live traffic conditions, to assess their suitability for actual field conditions with a possibility of developing design standards, at least in the Indian rural road context [28]. He conducted a systematic full scale experimental study on the structural performance of PCCBP for various cell thicknesses viz., 50 mm, 80 mm, 100 mm, 120 mm and 150 mm, of PCCBP over 100 mm thick water bound macadam (WBM) sub-base layer by using waste stone dust (byproduct of aggregates crushing) in place of the traditional river sand to economize the cost of construction. In the present paper, structural performance of PCCBP was evaluated by computing elastic layer moduli using a linear elastic layer theory based moduli backcalculation computer code BACKGA [22] from the surface deflection data obtained through Falling Weight Deflectometer (FWD). The layer elastic moduli obtained through BACKGA program were used as inputs to both KENLAYER and ABAQUS for comparing the deflection outputs with that of the experimental deflection data obtain through FWD. Subsequent sections will highlight the construction procedure adopted followed by finite element modelling via ABAQUS. Structural Analysis of Flexible Concrete Pavement - An Innovative Pavement Technique Yendrembam Arunkumar Singh, Konjengbam Darunkumar Singh, Teiborlang Lyngdoh Ryntathiang