Clay Ceramic Waste as Pozzolan Constituent in Cement for Structural Concrete.

Everton Dos Santos Barreto,Ronald Matheus Lobo Pereira,Afonso Rangel Garcez De Azevedo,Markssuel Teixeira Marvila,Karina Vaz Stafanato,Sérgio Neves Monteiro,Mujahid Ali

doi:10.3390/ma14112917

Abstract

Ceramic-based wastes generated from different industrial activities have increasingly been reused as construction material incorporated into concrete. In general, these wastes just replace common concrete aggregates such as sand and gravel. In the present work, waste from clay brick industries composted of kaolinite minerals were for the first time evaluated for their potential to be reused as the pozzolan constituent of a cement for structural concrete. Initial standard testes revealed that the clay ceramic waste (CCW) displays high pozzolanicity. Concrete was then produced with 10 and 20 wt.% of CCW mixed with ordinary Portland cement (OPC) as its pozzolan constituent. Compression strength of these concretes and of pure OPC as a control sample were determined in standard tests after 14 and 28 days of curing. In addition, the corresponding density, water absorption, capillarity and percentage of voids were measured together with the evaluation of microstructural indices by scanning electron microscopy. The initial tests confirmed that the CCW is indeed an effective pozzolanic potential due to a chemical effect by reacting with CH to generate C–S–H. Moreover, the technological results proved that CCW might effectively replace the pozzolan cement constituent for structural concrete.

Highlights

The study of materials with pozzolanic potential is a major focus in the application of cementitious materials, within the materials of science [1,2]
It should be noted that the values of pozzolanic activity obtained by the Luxán method were classified as follows: (i) if the value of the resistivity variation was less than 0.4 mS/cm the material was not pozzolanic; (ii) if the value was greater than 1.2 mS/cm, the material was highly pozzolanic; (iii) if the variation in resistivity was between 0.4 and 1.2 mS/cm, the material was medium pozzolanic
It is known that the degree of amorphism was directly related to pozzolanic activity, since the pozzolanic reaction was favored by this type of material

Summary

Introduction

The study of materials with pozzolanic potential is a major focus in the application of cementitious materials, within the materials of science [1,2]. Naturally found or as waste, are defined as materials that do not have agglomerating power on their own but finely ground in the presence of cement and water and have the potential to undergo hydration reaction for consolidating as a solid material [7]. For this purpose, in general, they have a siliceous or silico-aluminous chemical composition. Examples of industrial waste pozzolans are: rice husk ash [8,9] and sugar cane bagasse [10,11], and natural materials such as calcined clay [12] and volcanic ash [13,14]

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