Effect of polymeric aluminum on hydration hardening characteristics of lithium slag-cement composite cementitious materials

Abstract

Lithium slag is used as a supplementary cementitious material in cement-based materials due to its pozzolanic activity,but its lower hydration activity leads to a decline in the mechanical properties and durability of the cement-based material.In this paper,for the low degree of hydration of lithium slag in composite cementitious materials,an inorganic polymer aluminum was used as an activator to improve the hydration activity of lithium slag.The effects and mechanism of polymeric aluminum on hydration hardening of lithium slag-cement composite cementitious materials were investigated through macro properties of compressive strength and non-evaporable water content,and micro characteristics of hydration heat,mineral composition of hydration products and BSE microscopic morphology.The results indicate that the addition of polymeric aluminum significantly improves the compressive strength and non-evaporable water content in the lithium slag-cement composite cementitious material,which increases 26.8% and 5% respectively in the 28 d period.In the early hydration,polymeric aluminum accelerates the mineral phase dissolution and crystal growth in the lithium slag-cement composite cementitious material,and increases the total nucleation of hydration products.A large number of ettringite,hydration calcium aluminates,calcium hydroxide and amorphous hydration gels appeare in the hydration products,which promote hydration of lithium slag-cement composite cementitious system,the dissolution and erosion of lithium slag particles.

Keywords

• lithium slag
• cement
• composite cementitious material
• polymeric aluminum
• hydration characteristics