SCC with high volume of fly ash content

Abstract

Abstract. Self-compacting concrete is a very perspective building material. It provides great benefits during the construction of heavily reinforced buildings. SCC has outstanding properties such as high flowability, dense structure and high strength due to specific quality of aggregates, fillers, their proportion in mix, use of polycarboxylate-based superplasticizers. Main disadvantages of SCC are high price and the difficulty of obtaining a proper mix. Use of fillers, such as fly ash type F, is a way to make SCC cheaper by replacing part of cement. Fly ash also provides some technological and operating advantages. In this paper the influence of high volume (60% from cement) fly ash type F on the properties of concrete mixture and hardened concrete is investigated. The result of the work shows the possibility of reduction the cost of SCC using ordinary fillers and high amount of fly ash. The investigated SCC has low speed of hardening (7-day compressive strength at the range of 41.8 MPa) and high volume of entrained air content (3.5%).

Effect of ettringite morphology on the properties of expanding cement systems

“…The essential condition constraining the wide application of expanding cements and concrete based on them in building practice is the lack of an integrated approach to managing the processes of their structure formation [1,2] and properties, taking into account various combinations of "external" and "internal" factors of influence [3,4].…”

“…Ettringite, as a product of cement hydration, has been known for more than 130 years [1,2], and its formation kinetics and stability have been the subject of research in numerous studies [8,9]. At the same time, in most cases, ettringite was studied as a product of the chemical reaction of calcium aluminates and sulfates in aqueous solution [9,10].…”