How does the use of Lean Concrete Base (LCB) impact long term performance of overlying pavements?

Lean Concrete Base (LCB), also known as econocrete or cement-treated base, is a low-cement content concrete used as a base layer beneath asphalt or concrete pavements. The use of LCB significantly impacts the long-term performance of overlying pavements. Increased structural capacity is a key benefit. LCB provides a stiff and stable base layer that increases the overall structural capacity of the pavement system. This reduces stresses and strains in the overlying pavement layers, extending their service life. Improved load distribution occurs because LCB distributes traffic loads over a wider area, reducing stress concentrations and minimizing rutting and cracking. Reduced subgrade deformation is another advantage, the stiff LCB layer reduces the amount of deformation in the subgrade, preventing settlement and maintaining a smooth pavement surface. Improved drainage can result from the LCB layer facilitates drainage, preventing water from accumulating beneath the pavement and reducing the risk of moisture damage. Reduced frost heave can also occur when LCB is less susceptible to frost heave than granular base layers, which is beneficial in cold climates. However, there are also some considerations. Reflective cracking can occur. Cracks in the LCB layer can reflect through the overlying asphalt pavement, leading to premature failure. Joint design is critical. Proper joint spacing and design are essential to control cracking in the LCB layer and prevent reflective cracking. Construction practices are important. Proper mixing, placement, and compaction of the LCB are essential to ensure its strength and durability. Compatibility with the overlying pavement is important. The LCB and the overlying pavement must be compatible in terms of their thermal expansion and contraction properties to prevent stress concentrations. LCB provides a strong and stable base layer that improves the long-term performance of overlying pavements, reducing stresses, distributing loads, and improving drainage. However, careful attention must be paid to crack control, joint design, construction practices, and material compatibility to prevent reflective cracking and ensure optimal performance.