01628825

Component

Drying shrinkage in alkali activated slag mortars (AAS) are quantified in this paper. The activator dosage (Na₂O content) and the solution to binder ratios were varied from 3 to 5% and 0.4 to 0.5, respectively. Changes in length and mass were monitored over a period of time in accordance with ASTM C490. An ordinary portland cement (OPC) mortar mixture was also evaluated along with the AAS for the comparison purposes. Experimental results show that water loss is not the only reason for total drying shrinkage of AAS mortars; hydration kinetics of AAS played a significant role on the drying shrinkage behavior. It was also evident that the drying shrinkage in AAS mortars is significantly higher than OPC mortars. Internal curing (IC) and discrete polypropylene fiber addition are evaluated as potential shrinkage reducing methods. The results obtained from this work indicate that a 20% substitution of normal weight sand with saturated light weight aggregates (LWA) was efficient in bringing down the drying shrinkage of AAS mortars. Addition of polypropylene fibers (0.3-1%) reduced the drying shrinkage, mainly due to the better bonding between the slag cement and polypropylene fibers.

This paper was sponsored by TRB committee AFN40 Standing Committee on Concrete Materials and Placement Techniques. Alternate title: Quantification of Drying Shrinkage in Alkali Activated Slag Mortars and Validating the Efficiency of Various Shrinkage Mitigation Methods.

01618707

17-04788

English

13p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Fibers; Hydration; Kinetics; Lightweight aggregates; Mortar; Polypropylene; Shrinkage

Alkali-activated slag; Internal curing; Sodium oxides

Highways; Materials

Transportation Research Board Annual Meeting 2017 Paper #17-04788

TRIS, TRB, ATRI

Dec 8 2016 11:50AM