QUALITY CONTROL TESTS FOR VARIOUS LAYERS OF FLEXIBLE PAVEMENTS Er. HIRALAL AGRAWAL EXECUTIVE ENGINEER

EARTH WORK IN EMBANKMENT/SUB-GRADE CONSTRUCTION Various tests such as Procter Density (MDD, OMC), sieve analysis, Atterberg Limits, CBR, etc are to be done in the lab on the material/earth to find out its suitability for use in the construction of embankment/sub-grade. This is to be done before the start of the work. Determination of Field Dry Density (FDD) and %age of Compaction by “Sand Replacement Method” as per the Frequency given in Section 900 of MORT&H specification. Determination of Proctor density (MDD & OMC) of the actual soil being used at the site, on at least one or two samples for a particular source. Determination of Atterberg Limits i.e. L.L, P.L & P.I values, at least on one sample for a particular Source. Determination of Field CBR value at FDD on remoulded samples in the lab, to assure whether the required design CBR is achieved at field or not.

GRANULAR SUB-BASE (GSB)/ WET MIX MACADAM (WMM) Before execution of GSB/ WMM works, the materials to be used in the work are to be sent to the lab for mix-design i.e. to find out the proportioning of materials/ Job Mix Formula (JMF) and to ascertain the physical properties of the materials to find out its suitability for use in the work. Sieve Analysis or Gradation at field of individual materials to be used for preparation of GSB/WMM and compare with the corresponding grading obtained at the lab during the Mix-Design to assure whether the laboratory Job-Mix formula (JMF) can be out rightly used or not. If the Field grading of individual materials appreciably differ with that of Lab grading, a new JMF is to be worked out so as to satisfy the desired grading requirements as per MORT&H Specification. In that case also a fresh proctor Density (MDD/OMC) needs to be found at Lab.

Sieve analysis or gradations of mixed materials of GSB/WMM, both from plant site as well as field, to see whether that conforms to the desired grading requirement of MORT&H specification or not. Determination of Atterberg limits i.e. LL, PL & PI values of mixed GSB/WMM materials (425 micron passing). Determination of Field Dry Density (FDD) and %age of compaction of the compacted layer of GSB/WMM by “Sand Replacement Method (using large sand pouring cylinder) as per the frequency mentioned in section 900 of MORT&H specifications. In case of WMM, the Aggregate Impact Value (AIV) and Flakiness and Elongation Index (FI & EI) are also to be found out on coarse aggregates collected from the plant site on at least one sample for each source and to see whether they lie within the specified limits or not.

BITUMINOUS MACADAM (BM) Before execution of BM works, the materials to be used in the work are to be sent to the lab for Mix-design i.e. to find out the proportioning of materials/ Job Mix Formula (JMF) and to ascertain the physical properties of the materials to find out its suitability for use in the work. Sieve analysis or Gradation of individual materials at plant site (such as 20mm,10mm, 6mm to be used for preparation of BM)to be done and compared that with the corresponding grading obtained at lab during the Mix-design to assure whether the laboratory JMF can be out rightly used or not in the work. In case the field grading appreciably differ with that of laboratory grading, a new JMF is to be worked out satisfying the desired grading requirements as per MORT&H specification and used in the work.

Bitumen content and sieve analysis / Grading to be done on BM samples taken from plant site as well as laying site (Paver) to see whether that conforms to the desired grading/bitumen content requirements as per MORT&H specifications or not. 150mm size cores are taken to find out the density of compacted layer of BM @ one test per 700sqm area. These cores can also be used to find out the thickness, bitumen content and grading of the BM mix. The Aggregate Impact Value (AIV) Flakiness and Elongation Index (FI&EI) are also to be found out on coarse aggregates collected from plant site at least on one sample for each source to see whether that lie within the specifications limits or not.

DENSE BITUMINOUS MACADAM (DBM)/ BITUMINOUS CONCRETE (BC)/SEMI-DENSE BITUMINOUS CONCRETE (SDBC) Before execution of DBM/BC/SDBC works, the materials to be used in the work are to be sent to the lab for Mix-design i.e. to find out the proportioning of materials/ Job Mix Formula (JMF) and to ascertain the physical properties of the materials to find out its suitability for use in the work. Sieve analysis or Gradation of individual materials at plant site (used for preparation of SDBC/BC/DBM)to be done and compared that with the corresponding grading obtained at LAB during the Mix- design to assure whether the laboratory JOB Mix Formula (JMF) can be out rightly used or not in the work. In case, the field grading appreciably differ with that of the lab grading, a new JMF is to be worked out at laboratory satisfying the grading as well as other mix requirements as per MORT&H specification and used in the work.

Bitumen content and sieve analysis/ Grading to be done on SDBC/BC/DBM samples taken from plant site as well as laying site (Paver) to check whether that conforms to the desired grading/bitumen content requirements as per MORT&H specification or not. 150mm size cores are taken to find out the density of compacted layer of SDBC/BC/DBM @ one test per 700sqm area. These cores can also be used to find out the thickness, bitumen content and grading of the bituminous mix. The bituminous mix (SDBC/BC/DBM) is also to be collected from plant site to find out other properties of the mix such as Marshall Stability, flow, Air voids, GMM etc @ minimum 2 tests per day per plant to check whether it conforms to MORT&H Specifications or not. The AIV and FI&EI are also to be found out on various coarse aggregates at least on one sample for each source to see whether that lie within the specified limits or not.

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