Tremix concrete Tentative Design and Estimate

yogendra borse

Sample calculations for the design of a Tremix concrete road as per Indian standards for Estimate Purpose:

1. Subgrade Preparation:

Assuming the subgrade is compacted to 95% density, sub-base thickness =100mm, bulk density =1600 kg/m³

Weight = Thickness × Density × Compaction

= 0.1 × 1600 × 0.95 = 152 kg/m²

2. Concrete Mix Design (M30):

Water cement ratio = 0.45

Cement = 350 kg/m³

Water = 0.45 × 350 = 157.5 kg/m³

Fine aggregate:

= 0.5 × (1-0.45) × 350 /1600 = 73.44 kg/m³

Coarse aggregate:

= 350 +73.44 +157.5 –2 = 579.94 kg/m³

3. Design Parameters:

Design life = 15 years

Traffic = 450 PCU

Subgrade CBR = 5%

WMM CBR = 60%

WMM thickness =100mm

M10 base =150mm

Tremix layer =200mm

Grade = M30

Total traffic = 15 × 450 = 6750 MSA

Axle load:

(450×1000)/3000 = 150 axles/day

Design traffic:

= 6750×10⁶ /(365×24) = 768 MSA

CBR check WMM:

= (768×10⁶/10⁶)×(100/1000) = 76.8

Available CBR = 60% → SAFE

M10 base thickness:

= (768×10⁶ /(5×8.2))^(1/3) = 225 mm

Provided =150mm → SAFE

Tremix thickness:

= (768×10⁶ /(5×6))^(1/3) = 191 mm

Provided =200mm → SAFE

Reinforcement:

Bar =12mm, spacing =200mm

Area = π/4 ×12² = 113.10 mm²

Required steel:

Asf =425.14 mm²

Bars =425.14/113.10 = 3.76 ≈ 4 bars

Provide 4 numbers of 12mm bars per meter width

Abstract

Sr No.	Quantity	Unit	Description of Item	Rate	Amount in Rupees
1.1	761.25	Cubic Metre	Excavation for roadway in earth... (Item No. 2.11)	130.9	99647.63
1.2	187.5	Cubic Metre	Wet Mix Macadam... (Item No. 3.23)	2824.1	529518.75
1.3	281.25	Cubic Metre	Providing and laying PCC M-10... (Item No. 24.01)	7042.15	1980604.69
1.4	1875	Square Metre	Providing LDPE sheet... (Item No. 5.19)	33	61875
1.5	375	Cubic Metre	Providing M-30 Tremix concrete... (Item No. 5.22b)	10136.2	3801075
1.6	52.988	Metric Tonne	TMT FE500 reinforcement... (Item No. 14.01)	97458	5164104.5
Total Amount					11636825.57

Measurements

Sr No.	Item No.	Category	Description	No.	Length	Width	Height	Quantity	Unit
1.1	2.11	Road Subgrade	Excavation for roadway...	1	500	3.75+0.6	0.35	761.25	Cu.M.
Net Quantity								761.25	Cu.M.
1.2	3.23	Sub Base & Base	Wet Mix Macadam...	1	500	3.75	0.1	187.5	Cu.M.
Net Quantity								187.5	Cu.M.
1.3	24.01	PCC	M-10 concrete...	1	500	3.75	0.15	281.25	Cu.M.
Net Quantity								281.25	Cu.M.
1.4	5.19	Rigid Pavement	LDPE sheet		500	3.75		1875	Sq.M.
Net Quantity								1875	Sq.M.
1.5	5.22b	Rigid Pavement	M30 Tremix concrete	1	500	3.75	0.2	375	Cu.M.
Net Quantity								375	Cu.M.
1.6	14.01	Super Structure	Reinforcement steel	(500/4)/1000	3.75	0.785	12x12	52.988	MT
Net Quantity								52.988	MT

Comparative chart for Tremix concrete roads vs Pavement Quality Concrete roads

Parameter	Tremix Concrete Road Design	Pavement Quality Concrete Road Design
Subgrade preparation	Subgrade compacted to required density with minimum 100 mm granular sub-base.	Subgrade compacted to required density with minimum 150 mm granular sub-base.
Concrete mix design	Minimum compressive strength 30 MPa, maximum aggregate size 20 mm.	Minimum compressive strength 35 MPa, maximum aggregate size 20 mm.
Reinforcement	As per design requirement.	As per Indian standards, CRPC requires minimum 0.15% steel reinforcement placed in bottom third.
Thickness	150 – 200 mm	200 – 250 mm
Joint spacing	Generally 4–6 m. As per Indian standards, maximum spacing 5 m.	Depends on traffic and climate. As per Indian standards, maximum spacing 5 m.
Joint type	Dowel bars generally used.	Tie bars or dowel bars used.
Curing	Wet curing minimum 7 days. As per Indian standards, minimum 14 days.	Wet burlap or curing compound. As per Indian standards, minimum 7 days.
Surface finish	Smooth and uniform.	Textured surface possible for skid resistance and aesthetics.
Construction method	Tremix machine used for laying and leveling.	Paver or slipform machine used.
Cost	Generally lower.	Generally higher.

Selection depends on traffic volume, climate, soil conditions and budget. Both systems have advantages and should be chosen after technical evaluation.