Anti-crack performance of phosphorus slag concrete

Abstract

Anti-crack performance of concrete with phosphorus slag and fly ash singly and compositely added is investigated in terms of physical performance, hydration heat, dry shrinkage and creep. Index K is introduced to evaluate the crack resistance of phosphorus slag concrete. Results show that the strength of phosphorus slag concrete increases with the increase of fineness, and when surface specific area is greater than 300 m 2 /kg, the tendency slows down. Strength decreases with phosphorus slag content increasing and there is an optimal content existing between 30% and 50%. Both phosphorus slag and fly ash have obvious effect on elongating time setting, reducing hydration heat to a large extent and increasing creep value. Crack resistance of phosphorus slag concrete is divided into three stages, namely early hazardous stage, growth stage and later mature stage. With microstructure analysis, mechanism of effect of phosphorus slag on concrete performances and P and F on cement hydration is explored. It is concluded after comprehensive evaluation that the crack resistance of phosphorus slag concrete is approximate to, even to some extent better than that of fly ash concrete.

A composite cement of high magnesium sulphate resistance

“…PHS is a by-product of yellow phosphor production via electric furnace method, mainly consisting of calcium oxide (CaO) and silicon dioxide (SiO 2 ) (41,42). From chemical composition, it can be understood that PHS exhibits latent cementing properties with some pozzolanic character (reaction with lime), but it is less reactive than BFS.…”

“…From chemical composition, it can be understood that PHS exhibits latent cementing properties with some pozzolanic character (reaction with lime), but it is less reactive than BFS. The reason is that it is relatively poor in alumina content, in addition to its phosphorus oxide content that has deep influence on setting time of cement (41,42). Various properties of PHSblended cements have been investigated, and it has been determined that PHS content cements exhibit appropriate physical and mechanical properties under the effect of thermal, hydrothermal, and mechanical treatments.…”

“…Various properties of PHSblended cements have been investigated, and it has been determined that PHS content cements exhibit appropriate physical and mechanical properties under the effect of thermal, hydrothermal, and mechanical treatments. This type of composite cement presents 28-day compressive strength of almost 93 MPa at relatively high Blaine fineness of 450 m 2 /kg and a significantly better resistance against frost-salt attack (41)(42)(43)(44)(45).…”

Stochastic Modeling of Compressive Strength of Phosphorus Slag Content Cement

“…The CaO:SiO 2 ratio of PHS usually varies from 0.8 to 1.2. From chemical composition, it can be understood that PHS is a latent cementing material but less reactive than BFS [14,15]. The residual phosphorus of PHS has a retarding effect on setting time of Portland cement, and insufficient content of Al 2 O 3 also affects early properties.…”

“…Among these industrial wastes, only slags such as blast furnace slag (BFS) [5,7,8], steel slag [9][10][11], and phosphorus slag (PHS) [1,[12][13][14][15] have latent cementing property and have attracted attention of many researches [5,11,16]. In fact, the production of slag cements and Portlandslag cements results in resource conservation, reducing energy consumption and minimizing emission of GHGs, especially CO 2 [2].…”