UNAM makes sustainable cement out of construction waste

Construction and demolition waste (CDW)

in Mexico is a growing problem. Since there are not enough places for its disposal, construction waste often becomes a breeding ground for harmful fauna and causes diseases due to dust and soil contamination, not to mention that it can clog up sewages and drains and pollute water bodies during rain season.

However, doctor Tatiana Ávila Rendón and her team from the Engineering Institute of Mexico’s National Autonomous University (UNAM) , have found a way to reuse CDW to make new sustainable materials for construction.

Material Analysis

The engineers are working with two types of material: One is known as mixed waste or “all in one” waste, and the other is hydraulic concrete.

The first group is composed of leftover concrete (coming from the demolition of buildings, houses, sidewalks, etc). The second is made up of ceramic waste, plaster, paving cobblestones, and red brick, among others.

The materials are subject to different trials such as X-ray diffraction to identify their chemical composition; Scanning electron microscopy to understand its morphology; and mechanics to determine whether the material shows pozzolanic properties , which would mean that the CDW material can grow hard and more resistant in presence of humidity.

Thus, both types of residue were analyzed and the experts discovered that both showed positive pozzolanic properties. Furthermore, the materials were physically modified to reduce the particle size through a process of sifting and milling until the material showed an ash-like consistency.

In addition, they combined different percentages of Portland cement with the construction waste as a substituent material.

ENGLISH

Mexican scientists create Eco-friendly cement out of industrial waste

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