Effect of glass powder on microstructure of cement pastes

Abstract

The effect of glass powder (GP) on the microstructure of cement pastes was studied by using mercury intrusion porosimetry, thermogravimetric and differential thermal analysis, scanning electron microscopy, energy dispersive spectrum analysis and X-ray diffraction techniques. The compressive strength and alkali-silica reaction (ASR) expansion was also tested. The test results indicated that GP can increase the compressive strength of cement pastes and control the ASR expansion of mortars. With the increase in GP content, ASR expansion decreases sharply, although compressive strength decreases a little with a large amount of GP. The characteristic pore sizes decreased with some capillary pores transforming to interstitial pores or gel pores as GP content increased. GP could diminish pore size in cement pastes, which has important significance in improving durability. Incorporating GP in cementbased materials had little effect on the kinds of hydration products, but it significantly affected the amount of hydrates, especially calcium hydroxide. The amount of calcium hydroxide reduces with the increase in curing age and GP content. The microstructure of hardened pastes containing GP was relatively dense with an abundance of calcium silicate hydrate, whose morphology was different from the gel in pure cement systems. This kind of calcium silicate hydrate gel with a low calcium/silicon ratio had a network structure formed by irregular stumpy and lamelliform gel granules. GP has high pozzolanic activity.

Hydration Kinetics of Composite Cementitious Materials Containing Copper Tailing Powder and Graphene Oxide

“…CT particles, especially for the fine particles, can act as nucleation sites for cement hydration and accelerate its hydration. Similar results have been found for other mineral admixtures in our previous studies [20,21] time taken to observe the second exothermic peak decreases with the increase of the specific surface area. It indicates that the high CT fineness can accelerate the early hydration of composite cementitious materials.…”

Inhibitory Effect of Waste Glass Powder on ASR Expansion Induced by Waste Glass Aggregate

“…C–S–H gel with a low Ca/Si ratio is tobermorite whose gel strength is relatively high. It is the result of the pozzolanic reaction between reactive SiO 2 of WGP and Ca(OH) 2 of the initial cement hydration [ 28 , 29 ]. Additionally, excessive reactive SiO 2 continues reacting with the C–S–H gel with high Ca/Si ratio to form C–S–H gel with low Ca/Si ratio.…”

Kinetic Behavior of the Nonisothermal Crystallization of Highly Refracted Glass Microspheres

“…Glass microspheres (GMSs) are a new form of glass material . Given their form factor, GMSs typically have an adjustable refractive index, directional regression reflections, and high mechanical strengths . GMSs can be widely used as reflective markings for pavement roads, insulation materials, coating materials with low viscosity, and functional materials for the aviation industry .…”