The Role of Phosphorus Slag in Steam-Cured Concrete

Abstract

Steam curing is an effective method to increase the hydration degree of binder containing phosphorus slag. The role of phosphorus slag in steam-cured concrete was investigated by determining the hydration heat, hydration products, nonevaporable water content, pore structure of paste, and the compressive strength and chloride ion permeability of concrete. The results show that elevated steam curing temperature does not lead to new crystalline hydration products of the composite binder containing phosphorus slag. Elevating steam curing temperature enhances the early hydration heat and nonevaporable water content of the binder containing phosphorus slag more significantly than increasing steam curing time, and it also results in higher late-age hydration degree and finer pore structure. For steam-cured concrete containing phosphorus slag, elevating curing temperature from 60°C to 80°C tends to decrease the late-age strength and increase the chloride permeability. However, at constant curing temperature of 60°C, the steam-cured concrete containing phosphorus slag can achieve satisfied demoulding strength and late-age strength and chloride permeability by extending the steam curing duration.

Applications of Steel Slag Powder and Steel Slag Aggregate in Ultra‐High Performance Concrete

“…In general, UHPC consists of cement, silica fume, quartz sand, fiber, superplasticizer, and other constituents and exhibits very high compressive strength, high ductility, and outstanding durability [31][32][33][34][35]. High-temperature curing is usually used for UHPC, which is beneficial for the early hydration of cement and mineral admixtures [36][37][38].…”

Study on Preparation and Interfacial Transition Zone Microstructure of Red Mud-Yellow Phosphorus Slag-Cement Concrete

“…Therefore, the gelling property of YPS must be fully activated when increasing the YPS content in concrete. Previous studies have shown that YPS can refine the later pore structure of hardened paste, reduce the chloride ion diffusion coefficient, and improve the compressive strength and concrete durability [ 39 ]. Additionally, the activity of clinker minerals in the dissolution process improved when YPS fluorine (F) and phosphorus (P) were added.…”

Application of Ground Granulate Blast Furnace Slag-Steel Slag Composite Binder in a Massive Concrete Structure under Severe Sulphate Attack

“…As shown in Figure 5(b), these samples benefited from the activating effect of the high temperature on the hydration of the composite mineral admixture and the compressive strength of the concrete containing 50% composite mineral admixture is only slightly less than that of the plain cement concrete at 7 d. The compressive strength of the concrete containing 50% composite mineral admixture is slightly greater than of the plain cement concrete at 28 d, and the compressive strength of the concrete containing 50% composite mineral admixture is clearly greater than that of plain cement concrete at 90 d. These results indicate that, for temperature match curing, the concrete containing 50% composite mineral admixture reaches a satisfactory early compressive strength, as well as higher late-age compressive strength, although the compressive strength gain rate of plain cement concrete is low at late ages. This is because concrete cured at a high temperature results in nonuniformly distributed hydration products and a coarser pore structure in hardened paste [24][25][26]. However, the hydration degree of the mineral admixture increases at high temperatures, and the C-S-H gels produced during the hydration of the mineral admixture fill the pore structure of the hardened paste, as a result of which the negative effect of high temperature on development of compressive strength is weakened and the concrete containing mineral admixture cured at high temperature at early ages has a relatively high compressive strength gain rate [26,27].…”

“…This is because concrete cured at a high temperature results in nonuniformly distributed hydration products and a coarser pore structure in hardened paste [24][25][26]. However, the hydration degree of the mineral admixture increases at high temperatures, and the C-S-H gels produced during the hydration of the mineral admixture fill the pore structure of the hardened paste, as a result of which the negative effect of high temperature on development of compressive strength is weakened and the concrete containing mineral admixture cured at high temperature at early ages has a relatively high compressive strength gain rate [26,27]. In addition, the compressive strength of the concrete containing composite mineral admixture B is still greater than for the concrete containing composite mineral admixture A at all ages for temperature match curing.…”

“…Therefore, the concrete containing the composite mineral admixture obtains satisfactory resistance to chloride ion permeability Advances in Materials Science and Engineering when using temperature match curing. This is because the hydration degree of the mineral admixture increases at high temperature, as a result of which the pore structure of hardened paste is denser and the resistance to chloride ion permeability of concrete improves [26,27,29]. Figure 8(a) shows the compressive strength of the concrete during a sulphate attack test when using standard curing.…”