Investigation of the Engineering Properties of Micronized Zeolite Replaced Mortars

*Semih Ceylan and Salih Yazıcıoğlu* 

#### **Abstract**

 Engineering properties of mortars made with micronized natural zeolite that has big amount of reserves in Turkey have been investigated in this study. CEM I 42.5 R cement, standard sand, 10% replaced silica fume, 15 and 20% replaced micronized zeolite, and powder superplasticizer have been used upon preparing mortars. After 24 hours, 50 × 50 × 50 mm cubic specimens were taken out from the molds and cured at 23 ± 2°C at 7 and 28 days. Compressive strength tests were done on the 7th and 28th days. Water absorption and ultrasonic velocity tests were done to mortar specimens on the 28th day. According to the results, it is observed that usage of 15% micronized zeolite gave close results with 10% silica fume.

**Keywords:** zeolite, silica fume, mortar, engineering properties, pozzolan

#### **1. Introduction**

Concrete is the furthest expansively used artifact-building item in the world owing to its low cost, convenient durability, and mechanical properties as well as ease of being formed into different shapes and sizes. Although those benefits exist, peripheral problems also exist because of the manufacture of Portland cement as a constituent of concrete. The cement industry is assumed to be liable for approximately 7% of all CO2 produced [1, 2]. For this reason, decreasing the cement consumption is assumed a formula for sustainable progress. In addition, extending the functionality of cement and concrete materials by healing the mechanical and durability specifications has gained significance in recent years. The use of artificial or natural pozzolans as fractional use of Portland cement is recognized as a prevalent influential path to get those aims. For example, the general production of European cement is devoted to blended cements [3].

Pozzolanic materials usually combine with the hydrated calcium hydroxide Ca(OH)2 to make the hydrated calcium silicate (C–S–H) that is liable for the strength of hydrated cement pastes. In addition, rise in bulk density of concrete results as the mixture cavities are filled with little admixture components (micro filler influence) [4].

 Developing tendency of using natural zeolite in the cement and concrete world, many surveys have been done to explore its impression on concrete functions and compare that indigenous pozzolan with other pozzolanic materials. Generally, natural zeolites have suitable pozzolanic characteristics and their existence as pozzolan generate durability increase of cement and concrete composites [5].

 Silica fume is a waste material after getting ferrosilicon blends or silicon metal. One of the most useful usage area for silica fume is concrete. Owing to its physical and chemical and specifications, it can be stated as a reactive pozzolan. Concrete, which includes silica fume, may be very durable and very high strengthened. Silica fume can be gotten from concrete admixtures source and can be, basically, added during concrete manufacturing. Today in USA, the main reason of concrete deterioration is corrosion because of marine salts or deicing. Silica-fume concrete with a low water context is resistible to penetration by chloride ions. Many companies use silica fume in concrete in order to remedy existing structures or build new bridges [6].

The use of blended cements or supplementary cementing materials such as silica fume lowers the permeability, for that reason it increases the resistance of concrete against corrosion [7]. Owing to its high pozzolanicity and its excess fineness, silica fume is assumed to make low permeability concrete. The service life and durability performance and, evaluating the permeability of an existing concrete structure can be mentioned as an essential parameter. Because permeability of concrete is main key to find the durability of the structure [8, 9].

Little amount of silica fume, 5–10% by weight of cement, can be put to concrete. The outcome of decrease in slump is amended by putting much superplasticizers or water. When compared with the control mix, there is an important increase in compressive strength in each situation.

Silica fume is very mild due to of its higher fineness (about 20 pounds per cubic foot) and have handling problems. The problems have been prevailed to a percent by transporting and using silica fume in slurry in Norway. Patents have been presented to densify the fume for carrying without problem in Canada [10].

 Zeolite has big amount of reserves in Turkey. Silica fume is an expensive and very fine additive material (causes handling problems) that is generally imported from Scandinavian countries. The aim of this study is to find an approximate material to silica fume that exists in Turkey. Therefore, micronized zeolite, silica fume and control mixture were prepared for the experiments and the results were compared with each other.

#### **2. Methods and procedures**

#### **2.1 Materials**

#### *2.1.1 Cement*

 CEM I 42.5 R Portland cement, that is compatible with TS EN 197-1, was used in the experiment and its chemical body is given in **Table 1** and its strength specifications are given in **Table 2**. Specific bulk density of cement is 3.11 g/cm3 and specific surface is 3640 cm2 . The initial and final setting time of cement are, respectively, 165 and 280 minutes.

#### *2.1.2 Zeolite*

Clinoptilolite type micronized grained natural zeolite obtained from Rota Madencilik San. and Tic. A.Ş. was used in the experiments. Zeolite has the specifications of specific weight 2.3 g/cm3 , blain specific surface value 19,340 cm2 /g, BET value 45,862.4 m<sup>2</sup> /kg and its chemical composition exists in **Table 1** and laser gradation exists in **Figure 1**.

*Investigation of the Engineering Properties of Micronized Zeolite Replaced Mortars DOI: http://dx.doi.org/10.5772/intechopen.87836* 


#### **Table 1.**

*Chemical specifications of cement, zeolite and silica fume.* 


#### **Table 2.**

*Cement compressive strength specifications (MPa).* 

**Figure 1.**  *Gradation of zeolite.* 

#### *2.1.3 Silica fume, sand, and water*

 Imported silica fume from Norway was used in the experiment and its chemical composition exists in **Table 1**. CEN norm sand taken from Trakya Set Çimento A.Ş. compatible with TS EN 196-1 was used during the preparation of the mortars. Ankara tap water was used as mixing water during the experiments.

#### *2.1.4 Plasticizer*

About 2% melamine sulfonate-based super plasticizer was added to keep the workability constant and to compensate the negative influence of zeolite, silica fume addition on the slump of mortars.

#### **2.2 Experimental study**

 Mortars were prepared based on ASTM C 305, ASTM C109/C. All mixtures were prepared using 1375 ml sand, 242 ml water, 500 g binder and plasticizer and put into 50 × 50 × 50 mm cubic molds. Mortar mix ratios exist in **Table 3**.

Prepared cubic specimens taken out from molds after 24 h and cured in laboratory conditions in limed water at 25°C. Compressive strengths of the specimens at 7 and 28 days were measured. Strength values and unit dry weights exist in **Table 4**  and strength graph exists in **Figure 2**.

Flow table experiments were done during the experiments and 235–245 mm values were obtained.

Saturated unit weight, water absorption ratio of the specimens were also calculated and stated in **Table 5**.

Generally, it is observed that the unit weight of mortars prepared with additive are under control mortar. Dry unit weight of the other specimens is under dry unit weight of the control specimen. It is assumed that the reason behind that is, the


**Table 3.** 

*Mortar mix ratios.* 


#### **Table 4.**

*Mortar strength values and unit dry weights.* 

**Figure 2.**  *Strength values.* 

#### *Investigation of the Engineering Properties of Micronized Zeolite Replaced Mortars DOI: http://dx.doi.org/10.5772/intechopen.87836*

specific gravity of the specimens are lower than cement and their porosities are higher than cement.

 The absorption capacity of the concrete has relation with the total volume of the voids in concrete. Due to fineness of silica fume and zeolite, the voids in the paste and interface between aggregate and cement were filled with those mineral admixtures and therefore capillary voids were decreased. Values related to water absorption ratio exist in **Table 5** and **Figure 3**. The main function of the mineral admixtures is to increase the strength and decrease the capillary absorption. Concretes that have higher water absorption capacities have lower strength and durability.

 The time for sound wave to reach the other side of the concrete is higher in the concrete that has many voids. In other words, when the amount of voids in the concrete increases, the sound velocity decreases [11].

It is evaluated that the ultrasonic sound velocity increases in silica fume added mortars due to the filled microstructure. The values about ultrasonic pulse exist in **Table 6** and **Figure 4**.


#### **Table 5.**

*Water absorption ratios and saturated unit weight values.* 

**Figure 3.**  *Water absorption ratio.* 


#### **Table 6.**

*Ultrasonic pulse velocity values.* 

#### *ISBS 2019 - 4th International Sustainable Buildings Symposium*

**Figure 4.**  *Ultrasonic pulse velocity.* 

### **3. Conclusion**

All the experiments were done as planned. The results were compared and evaluated with each other, and it is revealed that this study should be widened with different approaches. The following conclusions can be drawn based on the experimental work that has been carried out and presented in this chapter:


*Investigation of the Engineering Properties of Micronized Zeolite Replaced Mortars DOI: http://dx.doi.org/10.5772/intechopen.87836* 

#### **Acknowledgements**

I would like to thank those for their contributions: VOTORANTIM/Elmadağ Cement for CEM I 42.5 R cement, DOST KIMYA for exported silica fume, Rota Madencilik San., and Tic. A.Ş. for micronized zeolite, DRACO for superplasticizer.

#### **Conflict of interest**

The authors do not have conflicts of interest. The authors alone are responsible for the matter and manuscript of this article.

#### **Notes/thanks/other declarations**

This project has been funded by Gazi University Scientific Research Projects with project no: 07/2018–2030. I would like to thank Kenan Toklu for his help during the cracking of the specimens.

#### **Author details**

Semih Ceylan\* and Salih Yazıcıoğlu Department of Civil Engineering, Gazi University, Ankara, Turkey

\*Address all correspondence to: smhceylan@hotmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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#### **Chapter 23**
