Analysis of the efficiency of adding silica, glass powder, Amazon chestnuts, and biopolymer on the mortar performance

The reuse of waste from different sectors has proven to be an interesting alternative and, with increasing research, it is possible to use it as raw material for the manufacture of building products, reducing the disposal and exploitation of natural resources. Associated with the above, in the restoration of historic buildings it is recommended to use lime-based mortars as the material provides “breathability” to the support, however, incompatibility (chemical and/or physical, and/or mechanical) with the current materials may occur. In this context, the objective of this research is to evaluate the physical, mechanical, and chemical properties of mortars made with a binder (hydrated lime or Portland cement): sand, in the proportion 1: 3: (by weight) where waste was added: silica fume, glass powder, Amazon chestnuts, and biopolymer (obtained from milk that was unfit for human consumption). Mechanical tests (compressive strength and diametral compression strength), absorption (immersion and capillarity), and ultrasonic pulse were carried out at 28 days of age. It was found that the addition of silica fume, glass powder, and chestnut enabled better performance in the properties of the lime mortar with gains of over 500% in mechanical properties (mainly in tensile strength) and a reduction of around 13% in absorption, however, it is harmful to cement mortars due to the high-fat content of the chestnut (around 42%), impairing its performance. Finally, it was found that waste contributes to the concept of technological innovation and sustainable development as it provides benefits to the performance of lime mortars.