http://mwi.usma.edu/concrete-barriers-false-counterinsurgency-idol/

“In his MWI article, ‘The Most Effective Weapon on the Modern Battlefield is Concrete,’ Maj. John Spencer argues that ‘concrete contributed to reducing the complexity of the urban environment, served as a major tool in establishing stability, and functioned as a powerful weapon against enemies using safe havens within the city.’

See:

The Most Effective Weapon on the Modern Battlefield is Concrete

Tommy Daniel responds that:

“Concrete is a useful tool when employed within a broader plan toward political reconciliation. On its own, it is more likely to exacerbate sectarianism and contribute to longer-term challenges to stability and security.”