Thermomechanical evaluation of new geopolymer binder from demolition waste and ignimbrite slits for application in the c
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MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.474
Thermomechanical evaluation of new geopolymer binder from demolition waste and ignimbrite slits for application in the construction industry D.L. Mayta-Ponce, P. Soto-Cruz and F.A. Huamán-Mamani Grupo de Investigación en Ciencia y Tecnología de Materiales-CITEM, Universidad Católica San Pablo, Arequipa, Perú.
ABSTRACT
Geopolymeric mortars with volumetric fractions of 0.6:1:0.3 for a binder powder, fine sand and sodium hydroxide solution (12M), respectively; have been fabricated by mixing the solid materials and the subsequent addition of sodium hydroxide solution 12M to form a workable paste, to later be cured for 28 days at room temperature. The microstructures of the fabricated materials reveal the existence of two phases with notable difference, one continuous to the geopolymer binder phase and another discontinuous of fine sand particles agglutinated by the binder phase. Mechanical compression tests are performed at a constant compression rate of 0.05 mm/min and at temperatures ranged from room temperature to 500°C. The mechanical results are ranged from 19 and 69 MPa for all the materials studied. On the other hand, there was an increase in mechanical resistance up to test temperatures of 200°C and the progressive reduction of resistance at temperatures above 200°C, with a fragile-ductile transition zone between 400 and 500°C and completely ductile behavior from test temperatures of 500°C.
INTRODUCTION In recent years, construction in Peru has had significant growth, which has generated a greater demand for construction materials. Traditional building materials such as Portland cement (PC) and clay bricks need a large amount of raw material to be fabricated. The PC, for example, plays a leading role in construction, because it is the main ingredient of mortars and concrete, however, the production of PC requires large amounts of raw material and generates a significant amount of CO2. It has been reported that 1.5 T of raw material is required to produce 1 T of PC and 0.9 T of CO2 is released into the atmosphere [1,2]. The knowledge of the harmful effects of global warming on
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our planet and a greater environmental awareness has allowed us to promote the search for alternative environmentally friendly construction materials [3], and geopolymeric materials are a very promising Eco-friendly alternative [4]. Repairs and/or infrastructure improvements generate a huge amount of concrete waste, mortar and clay bricks (construction and demolition waste - C&D), in addition to the difficulty of finding a suitable place for the disposal of C&D. There are several works based on the recycling of C&D, but most of them focus on its use as an aggregate of new mortars and concrete for non-structural applications [5
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