Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice

Table 1

Tolerable limits of different constituents in water for concrete mixing.

Constituents in mixing water	Tolerable limits as per different specifications	References	WHO standards for drinking [40]
pH	3–9	[22, 36, 39]	6.5–8.5
Suspended solids	2000 (mg/l)	[36]	500–1500
Dissolved solids	2000–50000 (mg/l)	[36, 39]
Organic solids	200 (mg/l)	[36]
In-organic solids	3000 (mg/l)	[36]
Sulphates	400–3000 (mg/l)	[21, 22, 36]	200–400 mg/l
Chlorides for plain concrete	360 to 4500 (mg/l)	[21, 22, 36]	200–600 g/l
Chlorides for reinforced concrete	500–1000 (mg/l)	[21, 36, 39]
Chlorides as cl, for prestressed concrete or bridge decks	500 (ppm)	[38]
Chlorides as cl, for other reinforced concrete in moist environments or containing aluminum embedment or dissimilar metals or with stay-in-place galvanized metal forms	1000 (ppm)	[38]
Zinc and lead	100–600 each (mg/l)	[21]	Zinc = 3 mg/l; Lead = 0.01 mg/l
Copper and manganese	500–600 each (mg/l)	Concrete prentice Hall, [41]	150 mg/l for Mg
Phosphates	100 (mg/l)	[21, 22]	0.4 mg/l max.
Nitrates	500 (mg/l)	[21]	10 mg/l max.
Sugars	100 (mg/l)	[21, 22]	-
Turbidity	2000 (NTU)	ACI, 1924:20:442–486	5–25 NTU max.
Sulphuric acid	6250 (mg/l)	ACI, 1924:20:442–486	—
Oil and grease	50 (mg/l)	[22]	—
Na + K + Ca + Mg	2000 (mg/l)	[39]	437 mg/l max.
Carbonates	1000 (mg/l)	Concrete prentice Hall, [41]	30–400 ppm
Bicarbonates	400 (mg/l)	Concrete prentice Hall, [41]	See total alkalinity
Sodium & hydrogen carbonates	2000 mg/l	[22]	Sodium = 200 mg/l max.
Alkalis as (Na2O + 0.658 K2O)	600 ppm	[38]	—
Total alkalinity as calcium carbonates	500 mg/l	[39], concrete prentice Hall, [41]	250 mg/l max.
Total solids	50,000 ppm	[38]	500–1500 mg/l