Westvaco Corporation

Lynden J Stryker

Frank J Ball

David V Braddon

Disclosed herein are low porosity aggregate-containing cement compositions comprising hydraulic cement containing substantially no calcium sulfate at least 0.1% alkali bicarbonate by weight based on dry ground cement, and at least 0.1% of a lignosulfonate or sulfonated lignin by weight based on dry ground cement, said aggregate-containing cement composition having been made at a water-to-cement ratio of between 0.4 and 0.15. Also, disclosed are methods for producing these low porosity aggregate-containing cements.

Low porosity aggregate-containing cement composition and process for

A method is disclosed for making low-porosity, free-flowing cement pastes with extended set times, improved workability and reduced expansion due to alkali aggregate reactions by combining hydraulic cements, especially portland-type cements, ground without gypsum with from 0.1 to about 1.0% of an alkali or alkaline earth lignosulfonate or sulfonated lignin, and 0.1 to 2.0% of an alkali bicarbonate, and combining with 20 to 40% water. Mixtures of aggregates with such low-porosity pastes made according to this process produce very workable mortars and concretes with extended set times and upon hardening have reduced expansion.

Low porosity cement and process for producing same

A method is disclosed for making low-porosity, free-flowing cement pastes with extended set times, improved workability and reduced expansion due to alkali aggregate reactions, by combining hydraulic cements, especially Portland-type cements, ground without gypsum with from 0.1% to about 1.0% of an alkali or alkaline earth lignosulfonate or sulfonated lignin, combining 20% to 40% of water with 0.1% to 2.0% of an alkali bicarbonate, and thereafter mixing together the combined cement and lignin with the combined water and alkali bicarbonate. As an alternate embodiment of this process, the alkali or alkaline earth lignosulfonate or sulfonated lignin may be added to the water-bicarbonate rather than blended directly with the cement. These low-porosity pastes when mixed with aggregates produce mortars and concretes that have extended set times and are very workable during processing.

Growing community of inventors

Mount Pleasant, SC, United States of America

Lynden J Stryker