Mechanical resistance of concrete used in the construction of informal housing in the City of Cajamarca 2025

Abstract

Informal construction is a persistent phenomenon worldwide, particularly in Latin America, where it is estimated that between 30% and 70% of urban buildings are constructed without technical supervision. In contexts of rapid urban growth and economic inequality, low-income populations access housing through self-construction, without complying with technical standards or structural safety regulations. This research evaluated the mechanical properties of informal concrete used in homes in the Huacariz, Mollepampa, and Nuevo Cajamarca sectors of the city of Cajamarca. Compressive, flexural, and tensile strength were analyzed and compared with the minimum values ​​required by the NTP, ACI, and RNE technical standards. The methodology adopted a quantitative, descriptive, non-experimental, and cross-sectional approach, applying standardized laboratory tests to 450 specimens extracted in situ from 30 homes. The results showed that informal concrete does not meet the minimum strength requirements, registering negative differences of up to 41.28% in compression (the minimum standard value is 210.00 kg/cm2), 52.92% in flexure (the minimum standard value is 38.00 kg/cm2), and 39.31% in tension (the minimum standard value is 19.82 kg/cm2). While the Nuevo Cajamarca sector showed better results than the other sectors, they still fall below the standards established in the regulations. This demonstrates that the informal concrete used in the evaluated homes does not meet the minimum structural strength requirements, posing a significant risk to the safety of their occupants