Title: Effects of "Second-Generation" High-Range Water Reducers on Durability and Other Properties of Hardened Cement

Author(s): D. Whiting and W. Dziedzic

Publication: Symposium Paper

Volume: 122

Issue:

Appears on pages(s): 81-104

Keywords: admixtures; air entrainment; chlorides; concrete durability; deicers; drying shrinkage; freeze-thaw durability; hardened concretes; permeability; plasticizers; scaling; water-reducing agents; Materials Research

DOI: 10.14359/2456

Date: 6/1/1990

Abstract:
A study was made of three commercially available "second-generation" high-range water-reducing admixtures (HRWR) using cement of high and moderate C3 A content and having a cement content of 545k lb/yd3 (323 kg/m3) and a water-cement ratio (w/c) of 0.50. Second-generation HRWR were used to reduce cement and water contents by 15 to 16 percent. Hardened concrete specimens were prepared and tested for freeze-thaw resistance, resistance to deicer scaling, permeability to chloride ions, drying shrinkage, and compressive strength development. In addition, the air-void systems of concretes containing second-generation HRWR and air-entraining admixtures were analyzed by linear transverse. Similar tests were performedon flowing concretes, where cement and water contents were maintained constant and second-generation HRWR were added to increase initial slump levels to 7 to 9 in. (75 to 225 mm). Results indicate that caution must be exercised when using these admixtures to reduce cement contents in concretes subjected to deicing chemicals, as performance may be adversely affected, especially in high-slump "flowing" concretes. Additionally, drying shrinkage may be moderately increased in these concretes.