The creation of a Job Mix Formula (JMF) for Full Depth Reclamation (FDR), Cement Treated Base (CTB), and Cement Treated Subbase (CTSB) using cement and NovoCrete stabilizer involves a systematic process to ensure the mix achieves the desired strength, durability, and field performance. The process begins with material characterization, where reclaimed or virgin materials such as milled pavement, soil, or aggregates are tested for gradation, moisture content, Atterberg limits, and strength parameters. If needed, steel slag or other coarse aggregates are blended to achieve the required gradation as per MoRTH Table 400-4.
Once the material properties are known, the appropriate dosage of additives is determined. Typically, Ordinary Portland Cement (OPC) is added in the range of 3% to 7% by weight of the base material—higher for CTB and FDR, and slightly lower for CTSB. NovoCrete is then added at about 2% of the cement weight. For instance, if 7% cement is used, the NovoCrete dosage would be approximately 0.14% by weight of the total mix. A Modified Proctor Test is conducted to determine the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD), which guides the water content required during mixing and compaction.
Trial mixes are then prepared in the laboratory with varying proportions of cement and NovoCrete. These mixes are tested for Unconfined Compressive Strength (UCS), with a minimum requirement of 4.75 MPa for CTB, and about 1.5 to 2.0 MPa for CTSB. Flexural strength tests are also conducted, with a target of at least 20% of UCS. Durability is evaluated using soaked versus unsoaked UCS values, with a minimum acceptable retention of 80%. Based on these test results, the mix that meets all structural and workability requirements is finalized as the JMF. Field verification trials are then conducted to ensure consistency and compatibility with actual site conditions.
This finalized JMF, developed in line with IRC:89-2019, MoRTH Section 400, and IRC:120-2015, ensures that the stabilized layers provide sufficient strength, moisture resistance, and long-term performance. The use of NovoCrete with cement enhances the mix’s binding capability, reduces water sensitivity, and allows for effective use of reclaimed or marginal materials in pavement construction.