Basics of Construction Microbial Biotechnology - Biotechnologies and Biomimetics for Civil Engineering - page 31

Table 2.2 Major biotechnological admixtures used in building materials (based on Plank 2003 , 2004 ; Mun 2007 ; Fytili and Zabaniotou 2008 ; Pacheco-
Torgal and Jalali 2011 ; Pei et al. 2013 ; and other sources)
Admixture Chemical type Biotechnological process Function, applications and dosage Estimated

price (US$)

Sodium
gluconate

Organic salt Biooxidation of glucose Set retarder; superplasticizer; water reducer; corrosion

inhibitor of the re-bar in concrete, used in gypsum plaster;
concrete mix; mortars, grouts, at dosage 0.1-0.4 %

500-850

Xanthan gum Polysaccharide Biosynthesis by bacteria

Xanthmonas campestris

Viscosifier (thickener), set retarder for self-consolidated
concrete, floor screeds, paints, 0.2-0.5 %

2,000-5,000

Welan gum Polysaccharide Biosynthesis by bacteria

Alcaligenes sp.

Viscosifier (thickener), set retarder for self-consolidated
concrete, floor screeds, paints, 0.1-0.5 %

2,000-5,000

Scleroglucan Polysaccharide Biosynthesis by fungi from genus

Sclerotium, Corticium, Sclerotinia,
Stromatinia

Thermostable viscosifier (no loss of viscosity at 90 C for
500 days), similar to xanthan gum

2,000-5,000

Succinoglycan Polysaccharide Biosynthesis by bacteria

Alcaligenes sp.

High shear-thinning behavior with temperature-induced
viscosity breakback for self-leveling compounds, soil
stabilization, 1-15 g/L of water

2,000-5,000

Curdlan gum Polysaccharide Biosynthesis by bacteria from

genera Agrobacterium or
Alcaligenes

Viscosifier (thickener), set retarder for self-consolidated
concrete, up to 10 g/L of water; can absorb water about 100
times

1,000-10,000

Polyaspartic
acid

Polyanionic
polyaminoacid

Chemical synthesis Biodegradable dispersant, inhibitor of corrosion in concrete,

air-entraining agent for concrete or mortar, set retarder for
gypsum

1,000-10,000

Sodium
alginate

Anionic
polysaccharide

Extraction from brown seaweeds Stabilizer, thickener, and emulsifier 2,000-10,000

Carrageenan Linear sulfated

polysaccharide

Extract of plants or red seaweeds Foam for protecting freshly poured concrete from premature

drying during highway construction

2,000-10,000

Dextran Polysaccharide Microbial synthesis 3,000-9,000