Synthesis and Characterization of Belite Cement with High Hydraulic Reactivity and Low Environmental Impact

Abstract

Cement industry is a large energy consumer and a major CO 2 producer. In cement manufacture, most of the CO 2 footprint is due to the decarbonation of limestone. The designing of new clinkers that require less limestone and less energy for their production is a means to significantly reduce the environmental impact of this binder, the most widely used in construction worldwide. The present study focuses on the elaboration and characterization of environmentally friendly cements of very low lime saturation factor, obtained at low burning temperatures with hydraulic properties similar to those of alite cement. Four types of complete belite cements of high hydraulic reactivity were obtained thanks to the stabilization of the most reactive phases of the belite using quick cooling associated to four different mineralizations. The obtained cements have been characterized for their burnability on the basis of the free lime content. Their chemical and mineralogical compositions were studied using Xray fluorescence, X-ray diffraction and optical microscopy. The composition and morphology of the belite were studied using scanning electron microscope coupled with EDAX. The compressive strength and hydration heat were determined according to French standards. The results show that the sintering temperature can be reduced to 1,100 • C which is 50 • C less than reported in similar researches and 350 • C less than alite cement, with an improvement of the chemical, mineralogical and structural properties of the belite. This results in a hydraulic reactivity comparable to that of ordinary alite cements, with 28-day compressive strength of 38 MPa.

Production of Belite Based Clinker from Ornamental Stone Processing Sludge and Calcium Carbonate Sludge with Lower CO2 Emissions

“…According to Stark et al [ 28 ], a reduction in the lime saturation limit leads to a higher belite content and a lower alite content. Bouzidi et al [ 29 ] stated that a completely belitic clinker could be produced with a CaO/SiO 2 ratio of 2. However, Clarizka et al [ 30 ] reported intense belite peaks with a CaO/SiO 2 ratio of 3, which decreased as the ratio decreased.…”

Physical and Chemo/Mechanical behaviors of fly ash and silica fume belite cement pastes- Part I

“…It is obvious that the compressive strength of all cement pastes improved and enhanced with the hydration times up to 90 days. This is mainly contributed to the normal hydration process of all cement phases, particularly the silicate phases of the cement (C3S and β-C2S) [5,6,39,[55][56][57]. The pozzolanic reactivity of HPFA and SF further improved and in turn increased the compressive strength much more than in case of its absence.…”

“…With cement batch B5 containing 20 % HPFA, the compressive strength was adversely affected, i.e. it decreased and were becoming lower than those of the blank [55][56][57][58].…”

Optimization of raw mixes with the study of the production of mixed cements and their physicomechanical characteristics

“…Как известно, низкоосновный клинкер обжигается при 1350 °С, но обладает невысокой гидратационной активностью в ранние сроки твердения. В странах СНГ и за рубежом разработано несколько способов, активизирующих процесс гидратации белита [8][9][10][11]. В основном все они предусматривают или воздействие добавок в процессе обжига, или обеспечение чрезвычайно высокой скорости охлаждения клинкера с тем, чтобы стабилизировать наиболее высокоактивные модификации белита.…”