The water treatment process at Toowoomba begins with the screening of the water, which is collected from dams. After screening process, the screened water is dosed with the coagulants at the flash mixer. During this process, the Poly aluminum Chloride and LT 25 are utilized so that there could be maximum PH factor for forming flocs. Next to this, agglomeration of flocs in flocculation chamber is processed, in which the approximate hydraulic detention time is twenty minutes. Once the process is done, physical process starts with the sedimentation, in which hydraulic detention time is 40 minutes. At last, water needs to be clarified through filtration process that eliminates the existing finer floc particles from the water. At the last stage, disinfection of water is processed with aim to eliminate all injurious and harmful microorganisms from the water.
Non-destructive Structural Testing
In order to measure the properties of concrete, three different tests are undertaken named as destructive structural test, semi-destructive test and non-destructive test. When measuring the properties of concrete through destructive test, it is observed that sample of concrete is usually damaged. The test carried out under the destructive test are compressive strengthen test, tensile strengthen test and flexural strengthen test. As far as the semi destructive test is concerned, it is observed that during testing, merely small part of the structure is damaged, which can be observed in core cutter test. The non-destructive test is an effective way to measure the properties of concrete, in which structure of concrete is not damaged. In order to undertake this test, distinct nature of tools and equipments are exploited such as rebound hammer, kolectric micro covermeter and ultrasonic pulse velocity. Best assignment help from the professional writers
Rebound Hammer (Schmidt)
The rebound hammer is used following the rule of spring that generates rebound forces. Some of the properties including young modulus (E), mass (ρ) and surface hardness can control this force. The process starts with the strike to the sample of concrete and read the rebound values. The table given below shows the summary of result taken after following the above-mention process.
Table 1: Results of Rebound hammer test
From the above table, it can be observed that the compressive strength of the concrete sample differ from its first position and other position. The reason of this change in the sample is surface hardness and split in the concrete. Thus, it differs ranging from 26 MPa to 54 MPa where the average strength is estimated at 26 MPa to 54 MPa.
Ultrasonic Pulse Velocity Testing Equipment (Pundit 7)
The ultrasonic pulse velocity testing equipment is used following the rule of sending ultrasonic pulse and observing the sound passed on through the media. This process uses the signal between 20 and 150 KHz, where the transmitter and receiver are present at the opposite sides of the concrete sample. Using this equipment, the homogeneity of the concrete can be observed, which further finds the cavities and approximates the depth of the surface split. Using the equipment for testing the above properties of the concrete, the sample is divided into gridiron as demonstrated in the table given below. Moreover, the output of the time taken by signals to shift from transmitter to receiver is also demonstrated in the table.
Table 2: Pundit test results
The above table shows indication for expected void around the grid shaded (E6). Additionally, a shallow crack around the grid B2 is also present. It can be seen that to ensure the position of the crack, both transmitter as well as receiver are linked in the A and E row. The table shown below depicts the result. Crack position table shows that crack is between the 5 to 7 cells.
Table 3: Crack position
It is found that strength and robustness of concrete structure mainly relies on the cover of reinforcement. In this way, covermeter is found as equipment, which is exploited for different purposes such as to approximate the cover density of already reinforced structure, to identify the position along with the direction of the rebar and to provide with the estimation of the bar diameter. Therefore, the usage of this equipment is effective in finding three readings of the concrete properties. This equipment is utilized through scanning the sample, where three different identification of the finding steel are found flashing light with high intensity and sharp sound. Upon scanning the given sample through covermeter, the results are found as depicted below.
Identifying steel in concrete sample
The above figure shows three steel bars along with their cover density. It can be seen from the figure that diameter of all the steel bar is 27mm while the steel bars start from the top third of the sample. Since there was limitation of the equipment, therefore it was not feasible to find the bottom of the bar.
Casting of Concrete Beam
In the concrete beam, the beam has different dimensions as shown in the figure below.
The volume and length of the concrete can be estimated by having 3 small cylinders that are dia=100, h=200 and 1 big cylinder that is dia=155, h=305. Upon calculating the above dimensions, the approximate volume of concrete is found as0.004714 and 0.005757m3 respectively. Additionally, the volume of the beam mould can be calculated as LxBxD=1400x250x100=0.035m3, resulting in 0.044 m3 that is the total volume of the required concrete. The sack of cement holds 0.0085 m3 and five or six sacks will be needed to conduct the above experiment.
The water required for each sack of cement is 2 liter, thus, required amount of water for six sacks will be 12 liter. In addition, there is need to have 10mm for the bottom bars as well as 4mm for the top bars. Therefore, the required length for the reinforcement will be approximately 1650mm with 700mm length for stirrup. It will further require 14 nos. of stirrups. Thus, to cast the concrete beam, the following actions were undertaken.
- Cutting and bending the main reinforcement
It is found that beam will require 10mm diameter steel bar for the major reinforcement along with 4mm MS bars for the shear link, therefore, at this step, these bars need to be cut into the calculated length as shown (1650mm) by the means of the available tools. After that, the bars will be bended at both ends so that they could give a cover of 25mm.
- Cutting and bending the stirrups
Stirrup will be cut into the length and will be bended by the means of the available tools. The number of stirrups available is fourteen and after first stirrup is made, it will laid on the mould while ensuring that it properly fits in the mould and then carries on creating other stirrups.
In order to develop the case, the steel, shear links and stirrup will be gathered together along with the spaces between stirrups of 100mm. To keep the steel and cage stable, they will be tied together.
Mould will be cleared as its dimensions are 1400x250x100. After clearing the mould, special mould oil will be applied to prohibit any dust in the mould. Next, testing cylinder will be cleaned.
To cast the concrete, electric mixer is exploited; whose capacity is three sacks of cement. The first mixer will be made by using three sacks of cement and 6.8-liter water. For the second mixer, 2 sacks of cement and 5.1 liter of water will be used.
Slump test is carried out to make sure that concrete mix is in working form and is enough moist. The slump test value of both mixtures is 55mm.
Once the cage is put in the mould, the concrete is laid in beam mould and in the cylinders, which will be 3small and 1 big in size.
In order to compact the concrete, vibrator is used as long as water appears in the surface. Since, more vibrators can decrease the amount of water in the concrete, therefore, in using the vibrator extra care is taken.