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Rules Engineer's Rejection of CAM Mix Valid, Rejects L&T's Claims
The adjudicating a key contractual row in the Mumbai–Ahmedabad High Speed Rail project has decisively ruled against , upholding the Engineer's rejection of the contractor's initial Cement Asphalt Mortar (CAM) design mix. In a unanimous decision dated , the three-member board dismissed L&T's claims for additional costs and a 14-month , finding that the company had failed to demonstrate .
The High-Stakes Design of a Critical Track Component
At the heart of the dispute was CAM, a specialised filling material placed between track slabs and the reinforced concrete bed in the ballastless track system. Under the for Package T-3, L&T bore primary responsibility for developing a CAM mix that met strict performance parameters. The contract provided a recommended composition in Table 18 of the technical specifications, expressly marked "for reference", alongside a requirement that L&T "deploy" an expert with at least three years of experience in Shinkansen high-speed rail CAM systems.
Between June and December 2023, L&T conducted extensive internal trials and developed what it called the "First Trial Mix", using domestically sourced components. Joint tests on appeared to show compliance with fresh-property and compressive-strength criteria. Yet on , the Engineer issued a (NOO), citing several deficiencies: the mix was approximately 7% lighter than the reference, omitted the air-entraining (AE) agent entirely, relied on unapproved constituent materials, and lacked formal endorsement from the deployed CAM expert,
Over the following 14 months, L&T attempted to address the Engineer's concerns through correspondence but did not submit a revised mix until . That second trial mix, which used Japanese-sourced components and included the AE agent, was approved in .
Competing Narratives on Compliance and Causation
L&T argued that the First Trial Mix had passed every test prescribed in the contract, that the reference composition was not mandatory, and that the Engineer's insistence on CAM expert sign-off had no contractual basis. The company contended that it was effectively compelled to abandon compliant Indian-sourced materials and procure costlier Japanese alternatives, incurring additional costs of ₹13.96 crore and JPY 9.62 crore by . L&T sought reimbursement and a 14-month time extension for the delay it attributed to the Engineer's "shifting and progressively expanded" objections.
The Employer, , countered that the First Trial Mix was fundamentally non-compliant. It pointed to significant deviations from the Shinkansen formulation, the absence of CAM expert supervision during development, and the critical omission of the AE agent—a component essential for long-term durability. The Engineer, they argued, had acted within its contractual mandate to verify that the mix would meet the required 50-year design life.
Cannot Be Assumed After Major Deviations
The conducted a detailed analysis of the contractual framework, focusing on the interplay between , , and the general conditions. The Board found that the contract did not grant L&T unrestricted . While the reference composition was indicative, any substantial departure—particularly omitting an ingredient like the AE agent with a documented role in freeze-thaw resistance and impermeability—triggered the need for under the guidance of the CAM expert.
Crucially, the Board noted that L&T had not produced
of the CAM expert's active involvement in the First Trial Mix, despite a service agreement requiring Nichireki to
"analyse the results of each trial mix and advise necessary modifications."
An email from the CAM expert in February 2025 confirmed that while fresh properties passed,
"it is impossible to say whether this is acceptable without conducting performance evaluations"
that could take up to 36 months.
The Board concluded that the test results relied upon by L&T pertained to "" under , not the separate "" regime governed by the Guide for Track Design. Since the First Trial Mix deviated from the empirically applied specifications without expert validation, the Engineer's NOO was justified. The subsequent approval of the Second Trial Mix, which followed the reference composition and included CAM expert endorsement, was consistent with contract requirements.
"" –
In its key observations, the Board stated:
"The test results referred to by the Contractor to declare the Trial Mix‑1 as ‘compliant’, are for the CAM Test ‘before execution’ and not for the ‘CAM Mix approval’."
It further held that
"the 14 months' time up till the approval of the second CAM mix is attributable to the Contractor squarely"
and that L&T's claims for additional
"do not arise."
The Board also rejected the allegation that the Engineer had compelled the use of Japanese components, noting that only polymer emulsion was required to be sourced from Japan and that the Engineer had never instructed L&T to procure other materials from Japanese vendors.
Final Order and Implications
The unanimously rejected all of L&T's claims, including those for additional costs, a 14-month , interest, and litigation costs. Each party was directed to bear its own legal expenses, while the DB's fees were to be shared equally. The decision underscores the importance of strict adherence to empirically based specifications in high-speed rail projects and clarifies that the Engineer's role in a extends beyond —it includes a to ensure long-term durability, especially where significant deviations from proven designs are proposed.
For the Mumbai–Ahmedabad corridor, the ruling provides clarity on the approval regime for CAM and reaffirms that contractors bear the risk of developing compliant alternative mixes without recourse to unless the Engineer has manifestly exceeded its authority.
