Investigation of the Effect of Larestan’s Pipeline Water on the Mechanical Properties of Concretes Containing Granite Aggregates

In this study, the compressive strength of the concretes made by the pipeline water of Larestan has been investigated. Although the used water for the concretes must be clean, standard, and generally drinkable water, in Larestan city, the pipeline water is nonpotable water; meanwhile, this type of water is still being used in the mixture of the concretes by companies and contractors. Since in the initial tests the compressive strength of the normal samples did not satisfy the standards, 50% of granite aggregate was replaced with the purpose of increasing strength of the samples. Then four types of samples were made, which are (1) normal concrete with pipeline water, (2) normal concrete with potable water, (3) granite concrete with pipeline water, and (4) granite concrete with potable water. The results showed that the compressive strength of normal samples is not standard in the case of using the pipeline water. This issue can be seen during the ﬁrst four weeks of the samples, whereas these samples are placed in the standard zone by replacing 50% of granite aggregate instead of normal aggregates. This may be attributed to the compensating eﬀect of granite aggregates in opposition to damaging eﬀect of water. Also, by using the granite aggregates in the mixture, the compressive strengths of the samples were standard and almost identical in both cases of pipeline water and tap water. As a result, the concretes made in this city must include additives for increasing the strength, or the tap water should be used as a replacement for pipeline water.


Introduction
e use of concrete in construction has widened recently. Concrete is a good material in the pressure situations, and thus it can have high performance as a column in structures. e compressive strength is the primary parameter in design, implementation, and quality control of the concretes. Moreover, compressive strength is the most useful parameter in the national and international agencies and other parameters such as modulus of elasticity, tensile strength, and compressive strain are expressed as a function of compressive strength [1]. ere are many important factors that can affect the specifications of the concrete and its strength, such as the degree of consolidation [2], water-tocement ratio [3], moisture [4], cement hydration [5], replacements [6], and type and size of aggregates [7,8]. Also, water is one of the parameters that can affect the specification of concrete. Usually, water represents about one-third of the whole concrete mixture and its direct influence is on the water-cement ratio. But another aspect of water influence is the content of water. American Concrete Institute (ACI) suggests that any drinkable water is suitable for use in the concrete. Currently, the use of some types of water like seawater is prohibited because of the high content of chloride as the chloride of water intensifies the corrosion of reinforcing [9]. e concrete industries consume about one billion cubic meters of water annually. is volume of water is just for mixing, so the enormous amount that must be added is used for washing the mixer, equipment, and pumps, as well as curing the concrete [10]. Studies of prediction showed that, until 2025, the 75% of water demand for concrete use will be in areas that have water reduction [11].
As a result, the investigation for replacement of other sources of water such as seawater [9], wastewater [10], underground water [12], and recycled water [13] has started. Some experimental work on compressive strength of concrete with 100% replacement of treated wastewater instead of tap water has been done. e two types of samples had the same curing process. e result showed that the compressive strength of samples with treated-water replacement is about 85-94% of normal concrete [14]. An investigation on the use of treated grey water (TGW) and raw grey water (RGW) showed an increased rate in the initial setting time and a decrease in the slump. Also, an increase in the compressive strength of TGW samples was seen but, in RGW samples, the compressive strength decreased [10]. e application of seawater, tap water, and salt water in the concrete has been investigated. e compressive strength of the samples was tested after 20 years. e seawater samples had earlier strength gain but they didn't show different compressive strength after a long time [15]. On the other hand, in some investigations, the compressive strength of concrete samples decreased due to the use of seawater. In this study, the difference between the compressive strength of tap water samples and that of seawater samples was less but, after 12 months, the difference got larger and reached 10 MPa in some cases [16]. Also, an investigation on the use of magnetic field treated water (MFTW) showed a better compressive strength of concrete compared to tap water concrete and it had a better strength at an early stage [17]. is early strength could happen because of the interaction between magnetic water and cement hydration. However, tap water in some countries or some areas of a country is very scarce. So finding a replacement for tap water in these areas is important and this new type of water should satisfy the criteria of standards.
Larestan is a city in the south of Iran. It is located in Fars province and is about 370 km from Shiraz and 220 km from Bandar Abbas (Figure 1). e prevailing climate there is hot and dry. So the water resources are very scarce in this area. In the past, the people used underground water or rainwater gathered in a kind of source called "Berkeh." Nowadays, with the development of cities, they became unusable and have been replaced by plumbing. But plumbing water in this city is not drinkable and the people must get the tap water from other sources or by using water desalination machine. Since getting tap water is not easy in the work zones, the contractors use plumbing water in their construction processes such as making concretes, mortars, curing, and so forth. e aim of this study is to investigate the properties of concretes that have been made by the plumbing water of this city. Although the plumbing water of this city is not drinkable, no one has investigated the effect of that type of water on the concrete structures. Since the water has a salty taste, it is probable that the water contains chloride ions. e presence of chloride is one of the main reasons for reinforcement corrosion and many other problems in the concrete [19] and also has an effect on the cement paste by raising Friedel's salt creation, increasing the Ca(OH) 2 content, and retarding the diffusion of chloride ion [20,21]. However, Shi et al. [22] investigated the effect of seawater on the mechanical properties, mineralogy, and microstructure of alkali-activated materials (AAMs) and showed that seawater is suitable for use as mixing water of the AAMs in the marine environment. Nevertheless, until now, no investigations were conducted on the effect of water on the concretes and steel bars which are made in this region.

Materials and Methods
As mentioned, there are many solutions to improve concrete performance. Some alternatives are improvement or replacement of aggregate, changing of mix design, or using additives. Based on Iran's concrete standard, the quality of the materials must satisfy certain criteria to prevent any damage to the structures. So, in tropical zones where the possibility of corrosion is higher, the use of more covers for reinforcement and making concrete with low porosity are inevitable [23]. e materials below have been used in this study to create concrete samples; further information on them is given in the following.

Cement.
Cement is the most consumed material around the world, of which people use four billion tons annually.
is is about 560 kg for every person [24]. Generally, the increase of cement in the concrete and consequently decrease of w/c ratio in the mix will produce stronger concrete [3,25,26]. Also, the quality of the concrete is important in compressive strength of the samples. e use of organic cement instead of normal Portland cement has been investigated. e compressive strength of organic samples was about 1/3 of normal samples. But this ratio was 1/2 in the tensile test [27]. e used cement in this study is type II Portland cement that is provided from Bandar Abbas. Since Larestan's cement factory produces white cement and there isn't any Portland cement factory in this area, almost all of the required cement of the region is provided from there. e physical and chemical properties (XRF analysis) of the cement can be seen in Tables 1 and 2 respectively.

2.2.
Aggregates. Sand, gravel, and crushed stone that have been known as natural aggregates form the most part of the concrete mix in both aspects of volume and mass. For any concrete construction, many mined aggregates are needed. Investigation on the aggregates consumption showed that more than 40 billion tons are consumed annually. From this huge amount, between 67% and 75% belongs to concrete making [28]. According to the standard, the used aggregate must be clean and durable and must have no harmful chemicals [29]. In some studies, the replacement of aggregate was mentioned as a good condition and in some cases the properties decreased. is can be referred to the origin of aggregates and their strength. But it is clear that the specifications of the aggregate such as shape, angularity, strength, and durability can affect the compressive strength of concretes. e effect of using marble as a replacement for natural coarse aggregate in concrete has been investigated. e natural aggregate was replaced by marble aggregate in the weight percentage of 0-100%. e results showed 14% better workability for marble aggregate samples and an increase of 40% and 18% in the compressive strength at 7 days and 28 days, respectively [30]. Figure 2 shows the used aggregates in this study, which were crushed aggregates and aggregates from local mines in Larestan (Figures 2(a) and 2(b)). Both fine aggregate and coarse aggregate were mixed with 50% of granite aggregate in the second type of concrete samples (Figure 2(c)). e reason for avoiding full replacement is the high cost of granite aggregate. Granite is one of the powerful aggregates that can be used in making concrete to increase the strength. Investigation on the use of granite aggregate as replacement for fine aggregate showed a 22% increase in the compressive strength [31]. Also, positive effects on the mechanical properties of concrete were seen in some studies   with the replacement of granite [32]. Also, the gradation curves for aggregates have been shown in Figures 3(a) and 3(b) for fine aggregates and coarse aggregates, respectively. e black-dashed lines are the margins of limitations between which the curves are located and they show the acceptable gradation of aggregates for concrete mixing.

Water.
e used water must be clean and must have no chemical content, and, generally, tap water from any source is suitable for making concrete. Any other types of water may have some effects on the properties of concrete or corrosion of the reinforcement [23]. As an example, the use of salty water like seawater is not permitted because after using it in making concrete it can cause some problems such as corrosion, swelling, and fracture [33]. Investigations on the use of magnetized water in making concrete showed that, in comparison to normal concrete, it has the same or even better compressive strength, while it decreases the required cement [34]. Regarding the country's vast territory, large variety of water quality is expected and it is possible that in some areas the quality does not meet the standards. So it seems necessary to investigate this issue. As a result, providing good quality of water for making and curing of concrete is inevitable.
One of these probable areas that are expected to not have a good quality of water is Larestan in the south part of Iran. e chemical properties of water in Larestan are shown in Table 3. is table is based on the monthly field measurements of the pipeline water characteristics of the city in different stations which have been reported by the local water administration. Also, for better comparison, the quantity of each indicator for drinking water of Tehran is shown as well. e water in Tehran is drinkable and it is known as standard water for making concrete in Iran. ese parameters were compared to acceptable limits in the Iranian Water Standard Book No. 1053 and the status was shown in the table. e acceptable limit consists of properties such as physical, chemical, and biological properties as well as radioactivity of the drinkable water.
Considering the above table, some noticeable point can be discussed. e water degree of hardness is very high and it is classified as very hard water based on the content of CaCO 3 in the classification of WQA (Water Quality Association) for water hardness [37] (Table 4). e temperature of the concrete mix is one of the most important parameters in the design steps, especially in the hot areas where the rate of water loss is higher. As can be seen, the temperature of Larestan's water is higher than the acceptable limits, so the vaporization of water must be included in addition to the previous parameters.

Experimental Method
In this study, four different types of mixture have been used. e first one is the samples made with plumbing water of the city and the second type is the samples made with drinkable water (or tap water). Moreover, the granite aggregates are used in these two categories to support concrete samples against the probability of weakness due to the effect of salty water. Normal water was used in the curing procedure for all the samples. As a result, four groups of samples were created and, by following the same curing procedure for all samples, the variable parameters can be seen from the compressive strength of normal samples and granite samples (Table 5). e drinkable water that was used had been got in the lab from the "water desalination system" that can be seen in Figure 4. is system works with the reverse osmosis procedure and the output is tap water. e ACI absolute volume method has been chosen for concrete mixture design and the slump of the mixture was taken at 6 cm. Also, the water-tocement ratio has been considered as 0.45 and the maximum aggregate size has been limited to 19 mm. e materials were mixed in the manual concrete mixture at the lab and then they were poured into the molds. e molds should be clean and clear of any physical or chemical wastes so they were cleaned and dried before use. e plastic molds were used in this study because they have no corrosion or sticking probability in making concrete ( Figure 5). e molds are cubical with the dimensions of 15 × 15 × 15 cm. Each mold was filled in three stages and each stage was consolidated by the minimum 10 tamping rod to avoid honeycombing concrete. Four different types of concrete were made in this study. e first one is the samples with the normal aggregates where the tap water was used. e second one has the same design and the type of water used is the pipeline water. e two other types of concrete were created by replacing 50% of aggregates by granite aggregate. Because there are 5 timing stages for breaking the samples, a total of 60 concrete samples were made in the laboratory. All samples were left in their mold for 24 hours to achieve the initial set of concrete. en the samples were named separately, moved to the curing place, and kept there until the time of the test (Figure 6). e curing conditions are as follows: (i) Samples are completely soaked in water (Figure 7) (ii) e samples were rotated for the same curing conditions for all sides of the samples (iii) e water temperature is kept at 30°C (iv) e type of water used for the curing procedure is tap water Since there are two di erent types of concrete samples, the curing system and condition were the same for both of them. e temperature of the water is controlled with the digital thermometer. For better analysis and less error in the test, 3 samples of each type of concrete were made and    e compressive strength test was based on the ASTM C39-86 and with the automatic hydraulic jack. Based on the concrete standards, the compressive strength of any concrete which is made using any type of water other than tap water must be at least 90% of the strength in the normal concrete. So this study has investigated the effect of Larestan's water on the short-term and long-term performance of concretes.

Results
Based on the previous plan for breaking the samples, they were broken on days 7, 14, 28, 56, and 90. For each test, three samples were used and the average strength was reported. e variance of outputs was acceptable for all samples because no dispersion larger than 4 MPa (±2 MPa) was seen in the results. Also, the samples were checked after the test for the probability of honeycombing concrete or any other problems, but no defect was seen in any of them. e main compressive strength that is presented in the tables and figures is the average measure of them. e output data of breaking the samples for both tap water and pipeline water used in concrete based on the age of the samples are presented in Tables 6 and 7 and Figures 8         Compressive strength (MPa) Figure 9: Comparison of compressive strength in tap water concrete and pipeline water concrete by replacing 50% of granite aggregate.
Advances in Civil Engineering 7 showed less reduction in the strength by using pipeline water. ere is more reduction on the initial days than on the nal days but, for the normal concretes, the reduction percentage was higher compared to granite samples. is can also be the e ect of granite aggregates on the shrinkage of samples or the in uence of water ingredient on the aggregates.
e percentage of the reduction in concrete strength has been shown in Figure 10 for normal concrete and granite concrete. Figure 10 shows that the total amounts of reduction for granite concrete samples are less than 10% for all the stages. Also, these samples showed less reduction in strength over time. But, for normal samples, the reduction of strength was higher than the limitation on the initial days and it continued until the 56th day. Even at the nal stage, the reduction of strength was still near to the upper limit and it can go higher with any intentional fault in concrete-making procedures.   )   10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40 Compressive strength (MPa) 14 28 56 90 7 Days Figure 11: Comparative chart of compressive strength results for normal concrete samples made by using tap water and pipeline water. 8 Advances in Civil Engineering e comparative charts of the compressive strengths of samples are shown in Figures 11 and 12 for normal concrete and granite concrete, respectively. e dashed line shows the maximum limit for each concrete mixture design. As a result, the compressive strength of normal concretes made by pipeline water is not acceptable in the initial days and it is very near to the lower limit of standard in the final stages. e standard strength is almost achieved on the 56th day. So any loading or proceeding of the construction must be stopped during this time. But by using the granite aggregates the reduction in the strength will be less and acceptable. is probably is the compensatory effect of granite on the weakness effect of pipeline water. Any other kind of reinforcement can be used for increasing the strength of the concrete in opposition to the weakness of pipeline water.
As a result, the use of normal water for making concretes in this city is not acceptable at least for the initial days and the concretes must be mixed with some reinforced materials for increasing the strength of the concretes. Also, the different type of cement may have an effect on the initial strength of concrete and increase it to be inside the limitations. Moreover, the effect of curing water must be studied on both mixed designs.

Conclusion
In this study, the effect of pipeline water of Larestan on the compressive strength of concretes has been investigated. Four groups of samples were made and tested to illustrate the effect of pipeline water on the concretes. Also, the granite aggregates were used as 50% replacement in concrete samples for their reinforcement with the purpose of increasing the strength.
e achieved conclusions are as follows: (1) e compressive strength of concrete made by using pipeline water is less than 90% of that of the same concrete made by using tap water and this is the opposite of the "concrete standard association." So, at this time, the concretes made in this city cannot satisfy the standard criteria. (2) By replacing 50% of granite aggregates, the compressive strength of concrete increased by more than 12%. is increase was higher for the samples made by using pipeline water. As a result, 50% replacement of granite aggregates is suitable for standardizing the concretes made in this city by using the pipeline water. (3) e effect of water on the strength reduction in the normal concrete was higher compared to that in granite concrete. It may be attributed to the damaging effect of pipeline water on the concrete strength which has been compensated by the granite aggregates. is reduction was more than 10% in the normal concretes (nonstandard) but for the granite concretes it was standard. (4) In the case of using normal pipeline water concrete, any loading or proceeding of construction must be stopped during the first 56 days due to the lower strength value of normal pipeline water concrete in the initial days. But it can be seen that in this city the concretes will load just after 7 days.  Figure 12: Comparative chart of compressive strength results for granite concrete samples made by using tap water and pipeline water.

Advances in Civil Engineering
Data Availability e results of the compressive strength of the samples, broken samples pictures, and pictures of work procedure are available from the corresponding author upon request.

Conflicts of Interest
e authors declare that there are no conflicts of interest regarding the publication of this paper.