Concrete work in a project usually holds the maximum

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## Factors that Affect the Cost of Concrete

**1. Material Costs**

Costs of materials and supplies and the associated shipping charges influence the cost of any concrete construction project.

**2. Labor Rates**

The local labor rates or wages specified by the state affect the expenditure of a project.

**3. Site Conditions**

The location and the prior site condition affect the cost of the project and concrete. Poor soil quality, wetlands, contamination, utility, environmental and traffic issues are few examples in this category.

**4. Schedule**

If the project schedule is too short for the type of work involved, then project costs tend to be on the higher side. This is especially true for projects with a significant liquidated damage clause in their contracts.

**5. Contingency**

A 10% contingency fund of the total expenditure is generally set aside by cement contractors to cover unforeseen costs. However, inflation and scarcity of materials and supplies might require a higher contingency of the range of 15-20%.

## Calculation of Cost for **1m**^{3} of Concrete

^{3}

Let’s consider the concrete mix of M15 (1:1.5:3), where, 1 is the part of cement, 1.5 is the part of fine aggregates and 3 is the part of coarse aggregates of

### 1. Assumptions:

**Bulk Density:**

1. Cement = 1500 kg/m^{3}

2. Sand = 1700 kg/m^{3}

3. Coarse aggregates = 1650 kg/m^{3}

### 2. Calculation of Materials for

1m^{3 } Concrete^{ }

Dry volume = Wet Volume X 1.54

Volume of cement required = (Dry volume X Cement ratio)/ Sum of ratio**Volume of Cement **= (1 X 1.54)**/**(1+1.5+3)

= 1.54/5.5

= 0.28m^{3}

Weight of the cement = 0.28 X 1500

= 420 kg.

**Volume of Sand **= (1.5 X 1.54)**/**(1+1.5+3)

= 2.31/5.5

= 0.42m^{3}

Weight of the Sand = 0.42 X 1700

= 714 kg.

**Volume of Course Aggregate**= (3 X 1.54)**/**(1+1.5+3)

= 4.62/5.5

= 0.84m^{3}

Weight of the Course Aggregate = 0.84 X 1650

= 1386 kg.

### 3. Cost Calculation

Cost of cement for 1 m^{3 }=

No of Bags = 420/50

=8.4 Bags

As per latest market rate, cost of 1 bag of cement is taken as Rs: 450

= 8.4 X 450

= 4200 Rs

Cost of sand for 1 m^{3 }=

As per latest market rate, cost of 1 m^{3} of sand is taken as Rs: 1400

= 0.42 X 1400

= 588 Rs

Cost of course aggregate for 1 m^{3 }=

As per latest market rate, cost of 1m^{3} of course aggregate is taken as Rs.2400

= 0.84 X 2400

= 2016 Rs

Therefore total cost of 1m^{3 } of M15 concrete is

=Cost of cement + sand + course aggregate

= 4200 + 588 + 2016

Say** Rs 6400**

## Additional Cost of Concrete

The above cost given is just for the raw materials of concrete. The complete cost of concrete includes the cost of mixing, transporting, compaction equipment, reinforcement, formwork and labour charges.

### 1.Mixing

The cost involved in the transportation of materials into the mixer and the mixer charges are added to the concrete.

### 2. Transportation

The mixed concrete is to transported to the concreting location with the help of machines and labours.

### 3. Compaction

The charges involved in the usage of compaction machines such as

### 4. Reinforcement

If the concrete is reinforced, the cost of steel and labour charges for the cutting and tieing of rebars is also calculated and added to the concrete works.

### 5. FormWork or Shuttering

If the concrete work is done for beam, columns or slab, the formwork required to hold the concrete is also added.

### 6. Skilled Labour

The man force required to mix, transport, place, compact and finish the concrete is added to the concreting work cost.

Read More:** 8 Types of Cost Estimates in Construction**

## Comments ( 2 )

1. The assumed bulk density of cement was 1500kg/m3. Elsewhere it’s 1440kg/m3. Is the bulk density based on the type of cement used?

2. Why weren’t the dry densities used in estimating so that we later on included the cement-water ratio?

3. “Dry volume = wet volume * 1.54”. Please, what is this 1.54??

NB:. I have gotten the concept behind the 1.54…