Abstract—The following article shows the steps for

developing a control system for a mobile volumetric concrete

mixer, in which you can control the strength of the material,

with the modification of the quantities of each aggregate such

as water, gravel, and sand using a microcontroller.

Index Terms—concrete, microcontroller, strength

I. INTRODUCTION

HE following document shows how a microcontroller

was installed to replace a control system based on

Programmable Logic Controller PLC [1]. The PLC of the

system was damaged, so it was necessary the installation of

a microcontroller [2] opening more possibilities to control

the automated system, this as well as a menu screen that

accepts the modification of the properties of concrete, in this

case the resistance. The machinery is mounted on a truck

tract as shown in figure 1

Fig.1. Mobile Concrete Dispenser.

Manuscript received April 04, 2016 ; revised April 09, 2016 . This work

was supported by the DIR.5210.16.2016/1.

M.W., P.K, P.M., S.M., P.P., G.W., are with the Department of

Vehicles M.W., P.K., P.M., M.S., P.P., W.G., A.S., are with the

Department of Vehicles and Fundamentals of Machine Design, Lodz

University of Technology ( email.: marek.wozniak.1@p.lodz.pl,

200272@edu.p.lodz.pl, przemyslaw.kubiak@p.lodz.pl,

193811@edu.p.lodz.pl, golebiowskiw@wp.pl, pawel.pluciennik@p.lodz.pl,

andrzej.szosland@p.lodz.pl ).

G.O.,L.C., L.G. are with the Department of Industrial Engineering and

Systems, University of Sonora (email: gozuna@industrial.uson.mx,

leonel.gomez@unison.mx, marcos.-lugo@hotmail.com).

This new control system was installed and an operator

was trained to modify the formulas of resistance of this,

using a keyboard and LCD screen, where the operator, via a

simple menu, can change the configuration of the mixture of

water, sand, gravel and additives for the production of

concrete in place by changing the strength of concrete.

II. PROTOTYPE

For the design of the control system it was taken into

account changes and improvements over the previous

control system, which could not alter the properties of

concrete due that the product was automatically dosed alone.

The new control system is able to modify the concrete

strength, only by changing the values in the following table

1 [3].

Table1 Ratios for concrete strength.

Strength Quantity for 1 m³

Proportions

Maximum

liters per

sack of

cement

(water) PSI Mpa Kg/cm²

cement

sacks (m³)

Sand

(m³)

Gravel

(m³)

1500 10.3 105 5.5 (0.22) 0.57 0.772 1:2.6:3.51

2000 13.8 141 6.1 (0.24) 0.549 0.786 1:2.25:3.22

2500 17.2 176 7.1 (0.28) 0.523 0.77 1:1.84:2.71 33

3000 20.7 211 7.6 (0.30) 0.523 0.77 1:1.72:2.54 29

3500 24.1 246 8.3 (0.33) 0.488 0.774 1:1.47:2.33 25

4000 27.6 281 9.1 (0.36) 0.47 0.772 1:1.29:2.12 22

4500 31 316 9.6 (0.38) 0.453 0.776 1:1.18:2.02 19

It only changes the value Kg/cm2 and the system opens or

closes the gates to control the quantities of cement, sand,

gravel and liters of water. The values in the table were

obtained from the following formula (1), (2), (3) and (4).

Cement = 0.0008Resistence + 0,364 (1)

Sand= -0.0006Resistence + = 0,6297 (2)

Gravel = 1x10-5Resistence + 0,7782 (3)

Water = 0.5062Resistence + 86,85 (4)

Control System Design for Volumetric Concrete

Mixer Using a Microcontroller

Ozuna Gustavo, Wozniak Marek, Gomez Leonel, Lugo Coporo Marcos, Kubiak Przemyslaw, Mierzejewska Paula, Szymanski Michal, Pluciennik Pawel,

Golebiowski Wlodzimierz, Szosland Andrzej

T

Proceedings of the World Congress on Engineering 2017 Vol II WCE 2017, July 5-7, 2017, London, U.K.

ISBN: 978-988-14048-3-1 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online)

WCE 2017

III. CONTROL

To control the system it was decided to use a

microcontroller 16F887 which works up to 20 MHz and has

35 inputs or outputs, depending on how you configure the:

14 analog inputs, 2 PWM ports, Serial Port, 3 programmable

timers, I2C port, an Electrically Erasable Programmable

Read-Only Memory (EEPROM) and a standby [4]. The

inputs and outputs were connected in the following order, as

shown in table 2 and table 3.

Table 2. System inputs

Input Description

Keyboard 4X4

Inductive sensor Count RPM of motor

On button Star the system

Stop button Stop the system

Encoder G Displays the position Gate Gravel

Encoder A Displays the position Gate sand

Table 3. System outputs

Output Description

LCD Display 16x2

Motor G Gravel Gate Controls

Motor A Sand Gate Controls

Water valve Water Flow Controls

The system structure can be seen in figure 2, where the

arrangement of inputs and outputs with respect to micro

controller is shown.

Fig. 2. Control system.

IV. DESIGN

The circuit design was performed in PCB Wizard which

was considered easy to install inputs and outputs connected

as pin strips and terminal blocks, and the use of optical

couplers to protect the control circuit because the sensors

operate with 12V and unlike the micro controller operating

with 5V [5] and operational amplifiers to condition the

signals [6], the circuit is show in figure 3.

Fig. 3. Control circuit.

The circuit already developed and installed can be seen in

the following figures 4 and 5, which show as installed and

protected because the equipment is cleaned daily with water

pressure and it must prevent a short circuit or sulfation of

terminals.

Fig. 4. Inside view of installed circuit.

Fig. 5. Exterior view of installed circuit.

Sensor I

Start

Stop

Enco G

Enco A

CO

NT

RO

L

LCD

Mot G

Mot A

Val A

Keyboard

Proceedings of the World Congress on Engineering 2017 Vol II WCE 2017, July 5-7, 2017, London, U.K.

ISBN: 978-988-14048-3-1 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online)

WCE 2017

V. COMPARISON OF RESULTS

According to the customer, each cubic meter of concrete

takes 216 liters of water depending on the concrete strength.

[3]. We know that for a cubic meter of concrete are needed

in total 1125 counts so we have to send 0192 liters per

count.

Five tests were conducted and the counts were recorded,

the kg of cement dosed and the average time required to

obtain 57 552 counts and 150 kg of cement per test therefore

required 2.6 counts per kilogram of cement. Data are in

Table 4 shown below.

Table 4 Results of sampling

TEST No. 1 2 3 4 5

counts 150 150 151 149 150

kg 56.9 57.36 57.8 57.68 58.02

Time 28.47 28.88 28.76 28.45 28.44

average counts

150.00

average Kg concrete

57.552

The results obtained are shown after performing 3 tests by

opening different gates which we will call A, B and C, with

3 repetitions each, coarse aggregate, ie, gravel and other 3

tests with fine aggregate, sand with their three respective

repetitions. The number of counts and the net weight in

kilograms of gravel and sand respectively were recorded.

Data obtained and the averages are presented in table 5-10.

Table 5. Sample gravel gate 1

A

TEST No. 1 2 3

Gate 1 1 1

Counts 151 152 150

Net weight (Kg.) 78.2 73.1 69.85

Average counts

151

Average Weight

73.716

Weight by counting as gate opening

0.488

Table 6. Sample gravel gate 2.

B

TEST No. 1 2 3

Gate 2 2 2

Counts 110 110 111

Net weight (Kg.) 86.5 90.6 87.85

Average counts

110.333

Average Weight

88.316

Weight by counting as

gate opening

0.800

Table 7. Sample gravel gate 3.

C

TEST No. 1 2 3

Gate 3 3 3

Counts 81 82 79

Net weight (Kg.) 97.3 93.2 98.05

Average counts

80.666

Average Weight

96.183

Weight by counting as

gate opening

1.192

The gate 1 obtained an average of 0.488 kg per count,

0.800 kg in gate 2 and 1,192 kg on the gate 3. These results

are shown in Figure 6. It is controlled the weight of gravel

count only by replacing the value of X with the number of

the open gate into the equation Y = 0.3521X + 0.1228.

Fig. 6. Graph of kg of gravel gate opening

The following tables show data obtained from samples for

sand. The weights are obtained by counting: for gate 1 are

0.683 kg, for gate 2 has an average weight of 1,282 kg and

gate 3, the average is 1,791 kg.

With these data the following equation Y = 0.5538X +

0.1449, with which we can obtain kg of sand per count was

obtained. In Figure 7, these results can be seen in a graph

comparing the count kg against the opening.

Table 8. Sand sample at Gate 1.

A

TEST No. 1 2 3

Gate 1 1 1

Counts 151 149 151

Net weight (Kg.) 99.55 104.4 104.45

Average counts

150.333

Average Weight

102.8

Weight by counting as

gate opening

0.683

Proceedings of the World Congress on Engineering 2017 Vol II WCE 2017, July 5-7, 2017, London, U.K.

ISBN: 978-988-14048-3-1 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online)

WCE 2017

Table 9. Sand sample at Gate 2.

B

TEST No. 1 2 3

Gate 2 2 2

Counts 80 80 80

Net weight (Kg.) 101.35 103.75 102.6

Average counts

80

Average Weight

102.566

Weight by counting as gate opening

1.282

Table 10. Sand sample at Gate 3.

C

TEST No. 1 2 3

Gate 3 3 3

Counts 50 50 50

Net weight (Kg.) 88.4 89.95 90.35

Average counts

50

Average Weight

89.566

Weight by counting as

gate opening

1.791

Fig. 7 Graph of sand kg gate opening

Table 11. Results of sampling.

Proportion Resistance

Theoretical Sample

A 1:2.6:3.51 105 114.3

B 1:2.25:3.22 141 152.9

C 1:1.84:2.71 176 165.5

D 1:1.72:2.54 211 203.1

E 1:1.47:2.33 246 260.3

F 1:1.29:2.12 281 276.8

G 1:1.18:2.02 316 329.6

Fig. 8 Graph of resistances

Resistance tests, generated in the volumetric concrete

mixer, to compare their resistance to the expected or

theoretical resistance [3] were also performed, it was

conducted seven destructive samples with different mixing

proportions of cement, gravel and sand resistance in the

laboratory of materials at the University of Sonora, where

tests were performed by mechanical compression. The data

obtained is shown in Table 11. In Figure 8, the plot results

of testing the resistance against the expected values of these

proportions in KgF / cm², shown that there is an error found

of 5.5%.

VI. SUMMARY

After making and installing the circuit, it is recommended

to test water and humidity filtration before putting to work

the system to avoid mishaps with the equipment. With the

control system operating satisfactorily, it is possible to stop

relying on a foreign supplier and lead to the expanded

creation of Mexican technology.

Acknowledgement:

This work has been supported by the MNISW/2014/DIR/374 GP II

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Proceedings of the World Congress on Engineering 2017 Vol II WCE 2017, July 5-7, 2017, London, U.K.

ISBN: 978-988-14048-3-1 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online)

WCE 2017