Interactions between Wastes and Binders - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 161

7.2.3 E FFECTS OF O RGANIC C OMPOUNDS ON C EMENT H YDRATION

Many organic compounds are added as deliberate admixtures to cement and concrete.
A selection of these and their effects, taken from Massazza and Testolin 5 , are
summarized in Table 7.4. Other organic compounds typically found in waste include
oil and grease, chlorinated hydrocarbons (e.g., trichlorobenzene), chelating agents
(e.g., ethylene diaminetetraacetate [EDTA]), phenols, glycols, alcohols, and carbo-
nyls. The effects of organic compounds on portland cement hydration are variable
and highly concentration dependent. For instance, triethanolamine and sugars are
normally retarders for C 3 S hydration, but can act as both retarders and accelerators

TABLE 7.4
Summary of Effects of Organic Additives on Cement Hydration

Organic Compound Purpose/Effect on Cement Hydration

Amines:
Ethanolamines:

Grinding aids
Increased water demand, retarded set, may increase early
strength
Accelerated set and hardening
Set accelerator, retarder

Monoethanolamine
Diethanolamine, triethanolamine

Melamine derivatives Set accelerators, retarders, plasticizers

Alcohols Grinding aids, retarders

Lignosulfonates and their
derivatives

Grinding aids, plasticizers;
Accelerated or retarded set
Gain in final strength for ordinary portland cement

Polycyclic sulfonates Superplasticizers; retarded set

Lignin compounds Grinding aids, accelerated set

Fatty acids and their salts
(acetic, ascorbic, citric, formic,
butanoic, decanoic, hexanoic,
oleic, oxalic, propanoic)

Grinding aids, set accelerators (particularly calcium formate),
retarders, plasticizers

Alternative treatment:
Sugars:
Lactose
Raffinose
Saccharose
Sucrose

Set accelerator, retarder

Phenolic resins Accelerators

Asphaltenes Grinding aids, accelerators

Diethylene glycol Grinding aid;

Unchanged or accelerated set

Ethylene glycol (surfactant) Grinding aid; retarded set

Hydroxycarboxylic acids Accelerators, retarders, plasticizers

Formaldehyde Accelerator

Cellulose derivatives Retarders