Southeastern Louisiana University - Computer Science ...csit.selu.edu/~csit/seniorprojects/SeniorProjects2018/... · Web viewMortar has been used for over 200 years as a binding agent

Rapid Setting Cement Based Mortars Using Nano Materials

______________________________________________________________________________

Rapid Setting Cement Based Mortars Using Nano Materials

Southeastern Louisiana University

Engineering Technology 493-01 Jordan Perez & Blake McHugh

Instructor: Dr. Mohammad Saadeh

Advisor: Dr. Mohamed Zeidan

Rapid Setting Cement Based Mortars Using Nano Materials1

Contents…………………………………………………………………………………………..1

Abstract…………………………………………………………………………………...2

Introduction……………………………………………………………………………………....3

Significance……………………………………………………………………………….3

Experimental Program….……………………………………………………………......4

Cembinder……………………………………………………..………………………….5

Research Design………………...………………………………………………….…………….6

Compressive Strength Test………………………………………………………………7

Flow Table Test………………………………….………………………………………..9

Normal Consistency Test………………………………………………………………..11

Vicat Needle Test…………………………………...…………...………………………………13

Conclusion & Continuation……………………....……………………………………………16

Timeline……………..……..…………………………...……………………………….………17 References……………………………………………………………………………………….18


Abstract

Advancements in robotic technologies have led to a consumer demand for a flowable, high-

strength, rapid-setting mortar. This study attempts to achieve such a mortar by adding colloidal

silica particles to a generic portland cement-based mortar. Mixtures containing silica particles

have displayed higher compression strengths in one, seven, and twenty-eight day trials compared

to the control. Increased compression strength for the experimental mortars show promising

results, though it has been at a trade-off for decreased flowability. Flowability results have not

yet proven unworkable; if mixtures become too stiff superplasticizer products will be added to

soften the mix. The most promising results have been obtained from the second five percent SiO2

mix containing .49 water-to-cement ratio. Projected further research involves more testing of the

five percent mix, and testing to determine if the mortar can be used in 3D printing and/or robotic

bricklaying.


Introduction:

Mortar has been used for over 200 years as a binding agent in masonry. It can be

composed using a variety of materials, chemical compounds and additives, but in its basic form,

mortar consists of cement (usually portland type), sand and water. Evolving technology such as

robotic brick layers and 3D printing have introduced a need for a faster setting mortars with

relatively higher flowability for pumping. Traditional mortars are ineffective in new technology

due to ranging viscosities, long setting-times, and low early-compressive strengths. Recent

studies have shown that adding colloidal silica particles to various cementitious materials

decreases set-time and increases early compressive strength of the concretes and mortars

(Deamer 2017). This study involves researching and testing viscosities, set-times, and

compressive strengths of mortar mixes containing colloidal silica particles.

Significance:

Early strength and rapid setting mortar can be used for a variety of applications in the

construction industry. Apis Cor, a construction company in Russia, recently 3D printed a 400ft2

house using a flowable and rapid-setting mortar (Deamer 2017). Researching rapid setting

mortar could potentially lower building costs, improve strength, and/or decrease construction

time of similar projects. Another application of a rapid setting mortar is for robotic brick layers.

Traditional brick masons can complete an average of 500 bricks per day. Recent advancements

in robotic brick laying has resulted in a robot that can lay a staggering 3,000 bricks per day

(Curtis). Laying 3,000 bricks per day calls for a rapid-setting and early strength type mortar.


Researching rapid setting mortar could decrease cost and/or increase production of robotic brick

layers.

Experimental Program:

Colloidal silica consists of nanoscopic silicone dioxide (SiO2) particles that have been

pre-suspended in liquid using ultrasonic mixing techniques. When added to a cement-based

mixture; silicone dioxide particles react with calcium hydroxide molecules in the cement to

produce Calcium Silicate Hydrate (CSH gel). CSH gel sites (Figure 1) are active crystalline

structures that ultimately determine the strength of the mix. As cementitious mixtures harden,

CSH gel sites expand and multiply, which explains the direct correlation between compressive

strength and time. A team from Shenzhen University, China have had similar results

experimenting with dry SiO2 particles (Deamer 2017). Compression test results from this

experiment and from the Shenzhen University experiment both show higher compressive

strengths in cements containing SiO2 than those without (Figure 2).

Figure 1. No CS/1% CS (Björnström 2006)


Cembinder®:

Cembinder® products are colloidal silicas developed by AkzoNobel Pulp and

Performance Chemicals. According to AkzoNobel, “Cembinder® performs exceptionally well as

a stabilizer, a durability enhancer, a set accelerator, and an early strength developer in

cementitious mixtures” (Cembinder for the Construction Industry). AkzoNobel produces several

Cembinder® products with slight variations in composition; the most important variations being

percentage silica by weight and average particle size. The products that will be evaluated in this

study are Cembinder 8™ and Cembinder 30™ (Figure 3)

Cembinder 8™ contains a higher concentration of SiO2 particles by weight than

Cembinder 30™. This means a higher percentage by weight can be achieved using Cembinder

8™ rather than Cembinder 30™ without over hydrating the mix. This information typically

becomes relevant at concentrations above ten percent SiO2, which is likely to occur later in this

study. Cembinder 30™ cannot be tested in high concentrations, it has a much smaller particle

size, which some studies suggest results in higher compressive strengths.

A 2006 study done by students at Wuhan University suggested that SiO2 particle size and

compression strengths were inversely related (Qing et al). This proved to not always be the case

in 2009 when a study conducted by Joan Schoepfer and Arup Maji showed a decline in

compressive strength for particles below 12nm (Schoepfer & Maji ). Analyzing data from this

study and information given in Table I. It can be hypothesized that mortar mixtures containing


Cembinder 8™ will have a higher compressive strength than mixtures containing Cembinder

30™.

Control 1% Si02 2% SiO20

1000

2000

3000

4000

5000

6000

Seven Day Compression Results (Figure 2)

Shenzhen University SouthEastern University

Com

pres

sive

Stre

ngth

(psi)

Cembinder Data (Table I)Properties Cembinder 8™ Cembinder 30™Silica (wt %) 50% 30%pH 9.5 10.5Viscocity (cP) 8cP 7cPDensity (g/cm3) 1.4 g/cm3 1.2 g/cm3

Na2O (wt%) .2% .55%Avg Particle Size (nm) 35nm 9nm

(Cembinder for the Construction Industry 2)

Research Design:

This study tests the effects of colloidal silica when added to a generic mortar mixture in

percentages calculated by cement weight (Table II). Percentages to be tested will be determine

based on data obtained throughout the study. Experimental mixtures are tested against the control

mixture, which contains like ratios of cement, sand, and water without the addition of colloidal

silica. After finding results for several mixes, the study tested the effects of changing water to

cement ratios from .56 to .49 at the 5% SiO2 mix, which displayed much higher early

compression strength compared to other mixtures (Compression Strength Results). Workability

of the samples are determined using the flow table test (ASTM C230/C230M). Setting time are


tested using the Vicat needle test (ASTM C191-13). Compressive strengths will be recorded at

one, seven, and twenty-eight days using the ASTM compressive test (ASTM C109-99).

Trial Mixtures (Table II)Mixes Cement

(g)Sand (g) Water (g) Cembinder 8

(g)Total Weight

W/C S/C

Control 758 2,273 426.3 0 3,458 .56 3.01% 750 2,273 418.7 15.16 3,458 .56 3.02% 743 2,273 411.1 30.31 3,458 .56 3.05% 720 2,273 388.4 75.8 3,458 .56 3.0

5%-02 787 2,273 362 78.5 3,422 .49 2.75

Compressive Strength Test:

Mortar compressive strengths for this study are obtained in accordance with ASTM Standard

C109. Currently, compressive strengths are being tested at 1,7, and 28-day intervals.

Compressive strength (ơ) equals maximum load (P) divided by surface area (A) (ơ=P/A). ASTM

Standard C109 allows maximum load in mortars to be found using a hydraulic press set to

increasing load on a two-inch cube at a rate of 200-400 lbf/s until failure (Figure 5). Once failure

occurs, the machine gives a maximum P value in lbf. Accepted surface area for each cube is

determined by multiplying the averaging of three equally spaced width measurements found

using digital calipers by three equally spaced depths also using digital calipers. No less than three

trials are conducted per mix at each interval. Accepted compressive strength for a mix at a

certain interval is found by averaging the three results (Compression Strength Results).


Figure 5. Compressive Failure

0 5 10 15 20 25 300

1000

2000

3000

4000

5000

6000

Compressive Strength Results

Control 1% 2% 5%

Time (days)

Com

pres

sive

Stre

ngth

(psi)


0 5 10 15 20 25 300

1000

2000

3000

4000

5000

6000

7000

Compressive Strength Results II

Control II 5%-02

Time (days)

Com

pres

sive

Stre

ngth

(psi)

Compression Strength ResultsMix 1-Day 7-Day 28-DayControl 2,159.1 psi 4,536.9 psi 5,332.6 psiControl II 2,179.6 psi 3,592.6 psi N/a1 % Si02 2,513.8 psi 3,953.0 psi 4,561.3 psi2% Si02 2,156.2 psi 4,634.3 psi 5,620.2 psi5% Si02 1,847.4 psi 3,804.4 psi N/a5%-02 Si02 2,701.9 psi 6,223.4 psi N/a

Flow Table Test:

The flow table test determines the workability of the mortar. The flow table test should be

performed as soon as the mortar is thoroughly mixed. Mortar that has a low flowability rate can

become too stiff (unworkable). In traditional mortar uses; water is added to increase the

flowability, however, this effects water-cement ratios for the mix, which can decrease CSH gel

sites and lead to low compressive strengths. During the test; a flow mold is placed in the center

of a flow table (Figure 6). The center mold should be filled in two layers, using a tamping rod to

tamp each layer 25 times. Once tamping is complete; the mold should rest for 30 seconds before

the mold is removed and the handle rotated 25 times within 15 seconds. This will cause the mold


to expand. Four measurements should be taken and averaged from the mix. Flowability is

((Average diameter-Mold diameter)/Mold diameter*100%).

Flow Table Test Procedure:

1. Make mortar (cement, water, sand, and any additives, if any).

2. When mortar is finished mixing, turn off the electric mixer.

3. Place the flow table mold on top of the flow table, directly in the center.

4. Pour mortar into flow table mold, filling the mold half way up.

5. Use a tamping rod to tamp the mortar in the mold 25 times.

6. Pour the mortar into the mold, filling it the remainder of the way.

7. Use the tamping rod to tamp it 25 more times.

8. When you are done tamping the second layer, use a straight edge to remove excess

mortar from the top of the mold.

9. Allow the mortar to rest/settle in the mold for 1 minute, as shown in Figure 6.

10. After mortar rests for 1 minute, quickly remove the mold.

11. Use the rotating handle (can be seen in Figure 6) on the right side of the flow table to

drop the table; turn the handle in a forward circular motion- 25 times in 15 seconds,

allowing the table to drop with each full rotation.

12. After 25 drops in 15 seconds, use a tape measurer to measure the diameter of the

flattened circular sample.

13. Take the average of 4 diameters of each sample (add up the dimensions and divide by

4).


14. The “flow” of a sample is measured in a percentage; use the formula ((Average

Diameter of Mortar – Inner Base Diameter of Mold) / (Inner Base Diameter of Mold))

x (100) to calculate the flow of each sample.

Figure 6. Flow Table

Normal Consistency Test:

The normal consistency testis one of the most time-consuming experiments that have been

performed throughout this project. The test is meant to determine the amount of water needed

for cement to react completely with water, which is then used for the Vicat needle test. The test

is conducted using the Vicat apparatus (Figure 7), and involves preparing pastes using only

cement, water, and silica, until the Vicat plunger penetrates 10mm. If the rod penetrates more

than 10 millimeters; the mixture is too wet and water must be reduced for the next test. If the rod


penetrates less than 10 millimeters; the mixture is too stiff and additional water must be added.

Once the plunger penetrates exactly 10 millimeters, the test is complete, and the Vicat needle test

can begin.

Figure 7. Vicat Needle

Normal Consistency Test Procedure:

1. Weigh out 650 grams of cement.

2. Place cement into electric mixer.

3. Add a controlled amount of water (begin with about 26%- of cement).

4. Allow cement to absorb the water for 30 seconds before mixing.

5. Run mixer on low speed for 30 seconds, then turn off.


6. Let cement mix rest for 15 seconds.

7. Turn mixer back on (medium speed) for 1 minute, then turn off.

8. Place gloves on your hands, and form a ball with the cement mix.

9. Toss the ball between your hands 6 times.

10. Place ball in the conical ring that comes with Vicat apparatus.

11. Remove the excess cement mix from the surface of the conical ring.

12. Lower the plunger rod until it reaches the surface of the cement mix.

13. Set the depth indicator (on the apparatus) on 0 millimeters.

14. Release the plunger rod, allowing it to penetrate the surface of the mix.

15. Use a timer, and allow the rod to penetrate the mix for 30 seconds.

16. After 30 seconds, record the penetration depth.

17. Normal consistency is reached when the plunger rod penetrates the Cementous mix 10

millimeters, after 30 seconds of penetrating.

18. If there is more/less than 10 millimeters of penetration, repeat this process again, and

add/remove water until you reach 10 millimeters of penetration.

Vicat Needle Test:

The Vicat needle test determines the initial and final setting time of each cement mix. Setting

time begins as soon as water is added to cement The initial setting time is determined by

dropping the Vicat needle into the mix until the needle penetrates 25 millimeters or less. Final set

time is determined by continuing the timer and dropping the needle until it no longer penetrates

the mix. The final setting time is elapsed time from mixing until the needle no longer penetrates

the mortar.


Control 1% 2% 5%0

30

60

90

120

150

180 Set Time(s)

Initial Set Time Final Set Time

Tim

e (m

in)

Flowability & Setting Time

Initial Set Final Set Flowability

Control 125 min 170 min 126.6%

1% 115 min 155 min 114.1%

2% 107 min 152 min 114.1%

5% 84 min 134 min 102.3%

Vicat needle Test Procedure:

1. Weigh out 650 grams of cement.

2. Place 650 grams of cement into electric mixer.

3. Add water (amount used to reach normal consistency).

4. Start a timer; this is the beginning of your initial set time test (when water touches

cement).

5. Allow water and cement to sit for 30 seconds; the cement will begin to absorb the water.


6. Turn mixer on low speed for 30 seconds, then shut off.

7. Allow the mix to rest for 15 seconds.

8. Turn the mixer back on for 1 minute, then shut off.

9. Put gloves on and remove a handful of the mix from the mixer; form a ball with the mix.

10. Toss the ball between your hands for a total of 6 times.

11. Place the ball into the conical ring that is provided with the Vicat apparatus.

12. Use a straight edge tool to remove the excess mix from the surface of the cone.

13. Lower the needle until it reaches the surface of the mix.

14. Set the depth indicator on 0 millimeters.

15. Release the needle, allowing it to penetrate the mix.

16. Repeat Step 15 every 15 minutes, until the needle penetrates the cement mix 25

millimeters or less.

17. Record the elapsed time from when the water was mixed with the cement to when the

needle penetrates the mix 25 millimeters; this time is known as the Initial Setting Time.

18. Do not stop the timer; you will continue the tests until you reach the final setting time.

19. Continue testing the mix every 15 minutes; when the needle no longer penetrates the mix,

the final setting time has been reached.

20. Record the elapsed time from when the water was mixed with the cement to when the

needle no longer penetrates the mix; this time is known as the final setting time.


Conclusion & Continuation:

Results show increased compressive strengths and decreased flowability for mortars

containing colloidal silica. The objective of this study is to obtain a flowable mortar with high

early compressive strengths. The second 5% mortar mixture, having water to cement ratio of

0.49, showed the most promising early compressive strength. Though flowability for this mix

was decreased, mortar is still workable. Continued research will be done with this mixture to

determine if the mix can be used in 3d printing applications. If the mix proves to be unworkable,

chemical additives may be tested such as super-plasticizers to improve flowability.


Timeline:

February Week One Jordan: ResearchBlake: Research

Week Two Jordan: PowerPointBlake: Proposal

Week Three Jordan: Review/edit ProposalBlake: Review/edit PowerPoint

Week Four Jordan & Blake ∙ L1 Begin Lab I (days 1-3) ∙ L1 Begin Day 1 compression test

March Week One Jordan & Blake ∙ L1 Finish Lab I (days 4-6) ∙ L1 Begin Day 7 compression tests ∙ L1 Finish Day 1 compression tests

Week Two Jordan & Blake ∙ L1 Finish Day 7 compression testsBlake: Begin Lab Report I

Week Three Jordan & Blake ∙ L2 Begin Lab II (days 1-3) ∙ L2 Begin Day 1 compression test ∙ L1 Begin Day 28 compression tests

Week Four Jordan & Blake ∙ L1 Finish Day 28 compression tests ∙ L2 Finish Lab II (days 4-6) ∙ L2 Begin Day 7 compression tests ∙ L2 Finish Day 1 compression testsJordan: Review/edit Lab Report I

April Week One Jordan & Blake ∙ L2 Finish Day 7 compression testsJordan: Begin Lab Report II

Week Two Jordan & Blake ∙ Edit Lab Report II

Week Three Jordan & Blake ∙ L2 Begin Day 28 compression tests

Week Four Jordan & Blake ∙ L2 Finish Day 28 compression tests

May Week One Jordan & Blake ∙ Prepare Final Presentation

Week Two Jordan & Blake ∙ Present


References

ASTM Standard C109-99, 2003, "Compressive Strength of Hydraulic Cement Mortars," ASTM

International, West Conshohocken, PA, 2003, www.astm.org.

ASTM Standard C191-13, 2003, "Time of Setting of Hydraulic Cement by Vicat Needle,"

ASTM International, West Conshohocken, PA, 2003, www.astm.org.

ASTM Standard C230/C230M, 2003, "Flow Table for Use in Tests of Hydraulic Cement,"

ASTM International, West Conshohocken, PA, 2003, www.astm.org.

Björnström, J. (Photograph). (2006, March 10). No CS/1% CS [digital image]. Retrieved from

Dr. Joakim Björnström research 2000-2006.

Cembinder for the Construction Industry[PDF]. (n.d.). Marietta, GA: AkzoNobel Pulp and

Performance Chemicals.

Curtis, S. (2017, March 27). Bricklaying robots set to replace human builders on hundreds of UK

construction sites. Retrieved February 19, 2018, from

https://www.mirror.co.uk/tech/bricklaying-robots-set-replace-thousands-10107529.

Deamer, K. (2017, March 7). This House was 3D Printed in Less Than 24 Hours. Retrieved

February 19, 2018, from https://www.livescience.com/58156-3d-printed-house-built-in

less-than-a-day.html.

Isfahani, F.T.,Redaelli, E.,Li, W., & Sun, Y. (2017). Effects of Nano silica on Early Age Stages

of Cement Hydration. Journal of Nanomaterials, 2017. Doi:10.1155

http://www.astm.org/


Qing, Y., Zenan, Z., Li, S., & Rongshen, C. (2006). A comparative study on the pozzolanic

activity between nano-SiO2 and silica fume. Journal of Wuhan University of Technology

Mater. Sci. Ed.,21(3), 153-157. Doi:10.1007/bf02840907.

Schoepfer, J. & Maji, A. (2009). An Investigation into the Effect of Silicon Dioxide Particle Size

on the Strength of Concrete. Retrieved March 31, 2018.


Computer Science & Industrial Technology Department Southeastern Louisiana University

Senior Projects Courses ET*93, ET494

The following project documents have been prepared by the student(s) and have been reviewed and approved by the undersigned advisor(s). The advisor(s) agree and approve that the document contents are appropriate and sufficiently detailed descriptions ofthe target proj ect and that the deliverables or results herein are appropriate outcomes that reflect quality of work that is in line with reasonable University level expectations, Engineering Technology program expectations, and accreditation expectations. Further all undersigned parties certify that all documents procedures and deadlines are in accordance with the course syllabus and other course requirements posted by the course instructor, and that the text of this present form has not been altered from the posted original.

Docmnent this fonn concems is:

Proposal Proposal Presentation Interim Report Final Report üFfna1 Presentation

Document this form concerns is:

O Proposal Cl Proposal Presentation C] Interim Report COFKal Report [A-Knal Presentation

Project Title:

Student names: (add lines as needed)


Student name (Print) Signature Date

oor„

Documents

Southeastern Louisiana University - Computer Science ...csit.selu.edu/~csit/seniorprojects/SeniorProjects2018/... · Web viewMortar has been used for over 200 years as a binding agent