Effect of Fly Ash Belite Cement on Hydration Performance of Portland Cement

Abstract

Fly ash belite cement is a green, low carbon cementitious material, mainly composed of hydraulic minerals of dicalcium silicate and calcium aluminate. In this study, we used fly ash belite cement to control the setting time, hydration heat, strength, composition and microstructure of hydration products in Portland cement. Results showed that incorporating fly ash belite cement into Portland cement can shorten the setting time, accelerate hydration reaction speed, enhance early hydration heat release rate of silicate minerals and reduce total hydration heat. Moreover, replacing composite cement with 30% FABC causes the 90 d compressive strength of pastes and mortars to reach 107 and 46.2 MPa, respectively. The mechanical properties can meet the requirements of P·F 42.5 cement. During the hydration reaction process, clinker and Portland cement have a synergistic hydration effect. Notably, hydration of fly ash belite cement promotes the formation of C-S-H gel, Ettringite and calcium hydroxide, thereby significantly enhancing long-term strength. With the increase of FABC contents, the long-term strength would be improved with the densification of hydration products. The porosity has a great influence on the strength, and the high porosity was the main cause of the low early strength of FABC pastes. FABC and its composite cement show promise for mass concrete applications and can be applied as a setting agent for Portland cement.

Time-Dependent Rheological Properties of Cemented Aeolian Sand-Fly Ash Backfill Vary with Particles Size and Plasticizer

“…Another explanation for the change in CAFB fluidity caused by adding plasticizers is its effect on cement hydration. Due to the increase of repulsive force among cement particles, fly ash particles and gangue particles, less hydration by-products are produced, and the viscosity of CAFB decreases with the decrease of solid content [40][41][42][43]. In addition, the EC monitoring results support the conclusion that the plasticizer postpones the hydration reaction in Figure 19.…”

“…This indicates that the repulsion betwe particles is much higher in the presence of plasticizers [37]. Another explanation for change in CAFB fluidity caused by adding plasticizers is its effect on cement hydrati Due to the increase of repulsive force among cement particles, fly ash particles and gang particles, less hydration by-products are produced, and the viscosity of CAFB decrea with the decrease of solid content [40][41][42][43]. In addition, the EC monitoring results supp…”

“…Once the cement is in contact with water, the chemical reaction usually begins [22]. In addition, it can be seen by electron microscope scan that CAFB with a maintenance age of 3 d can see C-S-H, CH, and ettringite filling around the aeolian sand and coal gangue, which affects the fluidity of CAFB slurry, as shown in Figure 20 [20,41,42,[46][47][48]. maintenance period owing to the hydration process of cement and the surface absorption of poorly crystalline C-S-H gels in Figure 16.…”

Experimental investigation into the mechanical and microscopic properties of cemented aeolian sand-coal gangue-fly ash backfill

“…It is not the same. with the growth of time, the number of hydration products is also growing [41][42][43].…”

Investigation of Mineral Admixtures on Mechanical Properties of Alkali-Activated Recycled Concrete Powders Cement

“…We then analyzed the effects of different proportions of GBFS and FA on geopolymers and the phase composition, mechanical properties and microstructure of AARCPC. The findings from this study highlight a valuable method for the high utilization of RCP and preparation of geopolymers with RCP [23].…”