FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2005

ABSTRACT

Title : “The Possibility of using Sawdust-Cement- Gravel Mix for Residential Floor Slabs”

Researchers : Allen Antonio, Rey Baldeo and Belen Bonifacio

Adviser : Engr. Elizabeth Rodriguez Rivera

School : FEATI University

Date : March 2005

Degree : Bachelor of Science in Civil Engineering

Over the years, engineers have conjured up ways to help us adapt to our changing world more efficiently. The development of new technologies not only helps us but also the environment. It ensures that all involved benefit from this. Nowadays, recycling is becoming an issue, as well as air pollution. At the same time, the construction industry is searching for ways to develop more lightweight materials.
Fine aggregates in concrete act as small binders that shape the whole structure. It gives the mixture its texture and consistency. Sand is the primary fine aggregate being used in any concrete structure. Sawdust however is a waste byproduct of sawmills, ejected when sawing lumber. It is both lightweight and cheap, meaning that it not only helps make it possible to build more lightweight structures but can also lower the cost of structures.
Our study focuses on developing an acceptable concrete mix that can be used for residential slabs. Since most structures in residential areas require less weight than high-rise structures, it might be possible to apply certain concepts with sawdust-cement-gravel mixtures. Also, concrete slabs compose almost 40% of the structures weight since they occupy a large area. If further development is pursued, it might be possible to apply sawdust as a fine aggregate substitute for lightweight structures and maybe more.
The whole of the project tries to implicate that sawdust-cement-gravel mix has an equal advantage than the standard mix of cement-sand-gravel. Both mixed in proportions classified as Class A mix with the proportions of 1:2:4 of cement, a fine aggregate, and a coarse aggregate respectively. Two sets of sample with three sample of each were made for a total of 6 specimens to be tested. The first set of three samples consists of the sawdust-cement-gravel mix, the second set of the ordinary concrete mix. Each set were mixed and molded in the same way and with the same volume proportions. After placement in molds, both sets were left to cure for a number of days. The then curing samples will then be tested at a given period of days specified under the National Structural Code of the Philippines or NSCP ( 7, 14, and 28 days). For added data, since time is against us, we decided to minutely alter the curing processes of the sawdust-cement-gravel specimens. The seven day specimen was not cured, the fourteen day specimen was soaked, and the twenty-eight day specimen was washed with a little bit of water every morning. After each curing period assigned, each group was tested under a hydraulic press machine for compressive strength test. The results of each period presented many peculiar findings.
During curing process, a decision was made to do different curing procedures and even none. The seven day specimen, which was not cured at all, showed a high early strength yield. The fourteen day specimen, soaked in water, was lower by 100 kg/cm3 or 1,419.4 psi. the last sample, cured every morning with water, stabled at about 220 kg/cm3 or 3122.68 psi. Results indicated that the average strength of the sawdust-cement-gravel mix was about 3000 psi. which, according to NSCP standards is between 2500 psi – 3000 psi., is still in accordance with minimum safety standards. Further analysis tells us that during the hydration process of concrete, the water taken in by the sawdust particles during mixing help hydrate cement particles in places where it is impossible to cure, mainly the center. Since found that the hydration of the center of structural components like columns take most of the time in construction, sawdust particles might help lessen curing time in half and could also eliminate the need to using chemicals to cure. Henceforth, proves that sawdust can be used in concrete mixes for residential floor slabs. With regards to the weight of the two sets of samples, an equally small amount of each was made and weighed. The results were dramatic since the sawdust-cement-gravel mixture was almost half of the standard mix’s weight then again proving its lightweight property. Another observation was that every sample tested to its failing point showed wood fiber bonding at work. Faces of the sample that were supposed to fall off once cracked didn’t, instead were being held together by strands of sawdust. To make it short, rather than splitting apart like usual, it just bulked up making it a remarkable feat for a man made object that rigid. This could prove helpful during structural collapses since concrete tend to fall right off in an event of a major crack occurring.
Using sawdust rather than sand has its advantages, among these advantages were mentioned in recent studies. These included: sound insulation and reduction of about -14 dB, thermal capabilities which allowed it to retain its temperature for longer periods of time, improved flexibility cause of its synthetic wood fiber bonding replicating that of trees, and more cost efficient because it is already waste byproducts, making sawdust a good compromise to sand.
Surely the engineering field might not approve incorporating organic materials into concrete because of their decomposing property and soft molecular structure but of course technologies change as well as time. More and more developments can be developed to improve this. If a man can build a house made out of sawdust, loose soil, clay and cement then surely it is possible to be able to build improved lightweight structures with merely waste materials and organic particles. An engineer’s job is to conceptualize and not to criticize. Broadening our minds towards environmental awareness does have its pro’s and con’s. This is the idea of pushing forward towards the twenty first century of development.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2004

ELECTRICITY GENERATION THROUGH RAINFALL

(Best Student Research Entry in FEATI Expo 2004)

By

Alfredo Abejero (Researcher)

Engr Tomas U. Ganiron Jr and Engr Alex H. Balaan (Advisers)

Engineers are always upon the innovation of advance science and unique technology, making them an infinite designer of the modern world. Considering the Philippine economic crisis calls the need of power scarcity. Furthermore, with the unpredictable weather condition, of which rain is mostly experienced, we have come up to formulate new innovation of generating electricity through rainfall. This innovation involves the principle of structural design of houses built in two-storey located in Zone 1 of the Philippine Code (as to NSCP specification), thermodynamics (converting potential energy to kinetic by turning the turbine, then to mechanical energy which will then produce heat and then to electrical for electricity) and hydrology.

Philippines and other countries are suffering from economic crisis that results to the depreciation of oil price and primary family needs. In this case, it is necessary to look for an alternative that will help reduce family expenses particularly electric consumption.

During wet season, excessive rainfall is usually the main problem of our country, which results to floods and sometimes-unexpected electric cutout. With this, through the principle of hydropower generating electricity, we have come to think conversion of rainfall to electricity. With the fast flowing jet of water directed onto the blades of the impulse turbine makes the rotor spin to generate electricity.

In the simplest form of hydropower, flowing water turns a turbine, which then turns the generator to produce electricity. The available water depends on the amount of water flowing, and also the pressure or the head of the water which will struck the blades to rotate.

As in the model house prepared, fill water into the container. Switch on the pump so as water will flow to the pipes with small bored-holes located above the model house. This serves as artificial rain. The rain will then flow down to the roof and then to the gutter so designed with an elevation that will give enough pressure in able to rotate the dynamo or blades of the turbine. As the blades rotate, this will now run the generator which will then produce electricity through heat.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS 2004

ABSTRACT

Title : A Study on Traffic Management along EDSA and Quezon Avenue

Researchers : Madison Santos , Gary Penados , Angelo Michael Mondejar and Arnel Notada

Adviser : Engr Tomas U. Ganiron Jr

School : FEATI University

Date : March 2004

egree : Bachelor of Science in Civil Engineering


.
The research principally aims at investigating the effectively of the newly implemented projects and policies as well as the capabilities of MMDA officials. This study is closely related conducted by the Traffic Operation Centre of MMDA. It involves traffic investigations and analysis regarding the newly implemented projects and policies Descriptive method was used in this general procedure. The subjects of this study are the vehicles passing through the EDSA and Quezon Avenue. The respondents were selected based on any of the following:
• A regular trip maker
• A Car user
• A passenger
• An MMDA official

A series of interviews, observations and hand-out questionnaires were given in this study. The questionnaires were in two forms, the English and Tagalog version. The former was translated into vernacular so as to conform to the common people. Interview Guide was also made to come up with an organized interview .Road surveys were done to have a deeper understanding about the problem. The researcher crossed overpasses and examined the effects of Yellow Lanes, U-turns and speed of the flow of vehicles. Likewise investigations of the most frequently encountered problems were observed.

Findings and Conclusions
In this study, the researcher found out that based on the answers obtained:
• Most of the drivers are against the implementation of U-turns.
• Graft and corruption is still rampant among traffic officials.
• Indiscriminate loading and unloading is the major cause of traffic build-up.
• Most of the respondents were satisfied with the projects that guarantees pedestrians
safety

Therefiore, MMDA is capable in administering its function thus it is proper to give recommendation to the authority as a government institution. U-turn slots are only applicable to light and moderate traffic, the implementation of this plan should not be practiced on major highways considering the frequent heavy –traffic situation of the Metropolis, similarly closing the intersections to facilitate the said plan is inappropriate when there is enormous number of vehicles traversing the highways. Moreover, the most serious cause of traffic build-up is indiscriminate loading and unloading of public transport which in return puts to waste the huge investment made for traffic management measures. Thus, it is recommended that road user view point should be further enhanced during the planning stage.Newly-installed infrastructures intended for the pedestrians impair the possibility of accident.That Yellow Lane Scheme shows a favorable impact to the vehicles. It is recommended to implement this scheme strictly for smooth flow of traffic.

RECOMMENDATION
To cope with problem in traffic congestions, there is a need to concentrate on the development and improvement of the public transport system. This is with hope that selected improvements might promote the mode shift of considerable private vehicle users to Mass Transit to reduce traffic congestion significantly.
Thereby recommending the following:

• Strict regulation of car ownership
• No garage, no car policy
• Higher fees on parking areas

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT RESEARCH 2005

ABSTRACT

Solving the Problem of Hydrogen Sulfide in Sewage Systems

By

Engr. John L. Relayson

(MS ENVI. ENG’G)

Hydrogen sulfide (H2S) is one of the gases found in untreated wastewater and is derived from the decomposition of the organic matter present in the wastewater containing sulfur or from the reduction of the mineral sulfites and sulfates. This gas is a result of septic condition during the collection and treatment of wastewater and has long been recognized by civil/sanitary engineers as a major problem in municipal wastewater systems. This colorless gas, known for its rotten egg odor, forms at virtually every point in a system from interceptors, force mains, and lift stations, to holding tanks, dewatering presses and drying beds. The unpleasant odor is caused by lack of oxygen. Since there is no constant supply of oxygen in the sewers, the oxygen dissolved in the water is consumed in a relatively short time, by both bacteria (Thiobacillus) and chemical reactions in the effluent. As long as oxygen is dissolved in the wastewater, no hydrogen sulfide will form. If, however, the oxygen present in the water is used up, the aerobic bacteria Thiobacillus begin to reduce the oxygen-rich compounds in the influent. In this way, first nitrates (NO3) and then sulfates (S04) are consumed. Gaseous nitrogen is produced when the nitrates are reduced. The formation of hydrogen sulfide occurs when the sulfates are reduced.
The unpleasant odor caused by the hydrogen sulfide is noticeable at concentrations of less than 0.1 ppm (parts per million) in air. Because of its low solubility and high volatility, hydrogen sulfide can be very easily released at collection points, pumping stations and other areas of the sewage system with high turbulence. If, however, hydrogen sulfide is not removed, it will have toxic effects on all organisms within the purification plant. Gaseous hydrogen sulfide and atmospheric oxygen from the free surface of a partly-filled sewage channel will be oxidized by Thiobacillus on the walls of the pipe to sulfuric acid. In the wastewater, itself, this acid is diluted, so that is has little influence on the pH (acidity) value of the effluent. However, there is a completely different situation on the walls above the water surface. Considerably higher levels of acid can build up there, which can lead to serious corrosion and premature destruction of concrete pipes. Foul sewage therefore has a high risk factor. In the past, reaction of local communities to the unpleasant odor of H2S was often viewed as the primary problem. But H2S also poses a serious problem for the structural integrity of the collection system and the STP (sewage treatment plant) as a whole. Millions of pesos are lost each year to corrosion caused by sulfuric acid formed from the interaction of the H2S with moisture. Of equal importance are the safety hazards associated with H2S. Hydrogen sulfide gas is a leading cause of death among workers in sanitary sewer systems. The methods for solving the problem can be divided into two groups: (1) elimination of the existing hydrogen sulfide, and (2) prevention of the formation of hydrogen sulfide.

Elimination of Hydrogen Sulfide
Oxidation rate of H2S with molecular oxygen is very low at ambient temperature and in the absence of catalysts. The only remaining possibility is to use a powerful oxidizing agent such as hydrogen peroxide (H2O2). As such substances are not specific, an excess over the stoichiometric requirement must generally be used. This has a negative effect on the cost-benefit ratio of these measures.

Preventing H2S Formation
The second possibility is to prevent the formation of H2S from the outset. This can be done in one of two ways:
1. Addition of Nitrates. As the added nitrates are more rapidly reduced by aerobic bacteria Thiobacillus than the sulfates already present in the effluent, the formation of H2S will be prevented as long as dissolved nitrates remain in the water. It is very difficult, however, to add nitrates accurately to fluctuating flowrates and compositions of effluent in a way which avoids harmful over-dosing and the resulting additional load to the effluent.

2. Maintaining a certain concentration of Dissolved Oxygen (DO) in the effluent. In order to maintain a concentration of oxygen in the wastewater, it must be constantly treated with oxygen. This can be achieved by dissolving air or pure oxygen. As air is used for maintaining the oxygen concentration in the effluent, it must be taken into account that air contains 70-80% nitrogen. Only a minor part of the gaseous nitrogen in the air is dissolved in the water because the nitrogen saturation level has often already been reached. This frequently causes the undissolved nitrogen to strip other toxic or odorous substances contained in the effluent. As a major part of the gas used is not dissolved, this usually leads to a drop in the flow performance of the pressurized sewer pipe due to the formation of gas pockets.

By using pure oxygen, the dissolving of gas can be controlled according to need. Equipment can be designed in such a way that an almost complete dissolution of gas can be achieved.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT RESEARCH 2005

INTEGRATING PROGRAMMABLE LOGIC CIRCUIT TOWARDS THE CIVIL ENGINEERING FIELD

By

Prof. Gerard V. Paguibitan (BS CE)

Programmable Logic Device or PLD is an electronic component used to build digital circuits. Unlike a logic gate, which has a fixed function, a PLD has an undefined function at the time of manufacture. Before the PLD can be used in a circuit it must be programmed. It is impossible to discuss PLD technology without mentioning some of the companies involved in its development. However, it is not the purpose of this article to list all manufacturers of PLDs. Inclusion or omission of a particular company from this article is intended as neither a recommendation nor a criticism.


Using a ROM as a PLD

Before PLDs were invented, read-only memory (ROM) chips were used to create arbitrary combinatorial logic functions of a number of inputs. Consider a ROM with m inputs (the address lines) and n outputs (the data lines). When used as a memory, the ROM contains 2m words of n bits each. Now imagine that the inputs are driven not by an m-bit address, but by m independent logic signals. Theoretically, there are 2m possible Boolean functions of these m signals, but the structure of the ROM allows just n of these functions to be produced at the output pins. The ROM therefore becomes equivalent to n separate logic circuits, each of which generates a chosen function of the m inputs. The advantage of using a ROM in this way is that any conceivable function of the m inputs can be made to appear at any of the n outputs, making this the most general-purpose combinatorial logic device available. Also, PROMs (programmable ROMs), EPROMs (ultraviolet-erasable PROMs) and EEPROMs (electrically erasable PROMs) are available that can be programmed using a standard PROM programmer without requiring specialised hardware or software. However, there are several disadvantages.

Programmable logic controllers
Before the advent of solid-state logic circuits, logical control systems were designed and built exclusively around electromechanical relays. Relays are far from obsolete in modern design, but have been replaced in many of their former roles as logic-level control devices, relegated most often to those applications demanding high current and/or high voltage switching.
Systems and processes requiring "on/off" control abound in modern commerce and industry, but such control systems are rarely built from either electromechanical relays or discrete logic gates. Instead, digital computers fill the need, which may be programmed to do a variety of logical functions. In the late 1960's an American company named Bedford Associates released a computing device they called the MODICON. As an acronym, it meant Modular Digital Controller, and later became the name of a company division devoted to the design, manufacture, and sale of these special-purpose control computers. Other engineering firms developed their own versions of this device, and it eventually came to be known in non-proprietary terms as a PLC, or Programmable Logic Controller. The purpose of a PLC was to directly replace electromechanical relays as logic elements, substituting instead a solid-state digital computer with a stored program, able to emulate the interconnection of many relays to perform certain logical tasks. A PLC has many "input" terminals, through which it interprets "high" and "low" logical states from sensors and switches. It also has many output terminals, through which it outputs "high" and "low" signals to power lights, solenoids, contactors, small motors, and other devices lending themselves to on/off control. In an effort to make PLCs easy to program, their programming language was designed to resemble ladder logic diagrams. Thus, an industrial electrician or electrical engineer accustomed to reading ladder logic schematics would feel comfortable programming a PLC to perform the same control functions.
PLCs are industrial computers, and as such their input and output signals are typically 120 volts AC, just like the electromechanical control relays they were designed to replace. Although some PLCs have the ability to input and output low-level DC voltage signals of the magnitude used in logic gate circuits, this is the exception and not the rule. Signal connection and programming standards vary somewhat between different models of PLC, but they are similar enough to allow a "generic" introduction to PLC programming here. The following illustration shows a simple PLC, as it might appear from a front view. Two screw terminals provide connection to 120 volts AC for powering the PLC's internal circuitry, labeled L1 and L2. Six screw terminals on the left-hand side provide connection to input devices, each terminal representing a different input "channel" with its own "X" label. The lower-left screw terminal is a "Common" connection, which is generally connected to L2 (neutral) of the 120 VAC power source. Inside the PLC housing, connected between each input terminal and the Common terminal, is an opto-isolator device (Light-Emitting Diode) that provides an electrically isolated "high" logic signal to the computer's circuitry (a photo-transistor interprets the LED's light) when there is 120 VAC power applied between the respective input terminal and the Common terminal. An indicating LED on the front panel of the PLC gives visual indication of an "energized" input: Output signals are generated by the PLC's computer circuitry activating a switching device (transistor, TRIAC, or even an electromechanical relay), connecting the "Source" terminal to any of the "Y-" labeled output terminals. The "Source" terminal, correspondingly, is usually connected to the L1 side of the 120 VAC power source. As with each input, an indicating LED on the front panel of the PLC gives visual indication of an "energized" output: In this way, the PLC is able to interface with real-world devices such as switches and solenoids. The actual logic of the control system is established inside the PLC by means of a computer program. This program dictates which output gets energized under which input conditions. Although the program itself appears to be a ladder logic diagram, with switch and relay symbols, there are no actual switch contacts or relay coils operating inside the PLC to create the logical relationships between input and output. These are imaginary contacts and coils, if you will. The program is entered and viewed via a personal computer connected to the PLC's programming port.


Consider the following circuit and PLC program:
When the pushbutton switch is unactuated (unpressed), no power is sent to the X1 input of the PLC. Following the program, which shows a normally-open X1 contact in series with a Y1 coil, no "power" will be sent to the Y1 coil. Thus, the PLC's Y1 output remains de-energized, and the indicator lamp connected to it remains dark. If the pushbutton switch is pressed, however, power will be sent to the PLC's X1 input. Any and all X1 contacts appearing in the program will assume the actuated (non-normal) state, as though they were relay contacts actuated by the energizing of a relay coil named "X1". In this case, energizing the X1 input will cause the normally-open X1 contact will "close," sending "power" to the Y1 coil. When the Y1 coil of the program "energizes," the real Y1 output will become energized, lighting up the lamp connected to it: It must be understood that the X1 contact, Y1 coil, connecting wires, and "power" appearing in the personal computer's display are all virtual. They do not exist as real electrical components. They exist as commands in a computer program -- a piece of software only -- that just happens to resemble a real relay schematic diagram. Equally important to understand is that the personal computer used to display and edit the PLC's program is not necessary for the PLC's continued operation. Once a program has been loaded to the PLC from the personal computer, the personal computer may be unplugged from the PLC, and the PLC will continue to follow the programmed commands. I include the personal computer display in these illustrations for your sake only, in aiding to understand the relationship between real-life conditions (switch closure and lamp status) and the program's status ("power" through virtual contacts and virtual coils). The true power and versatility of a PLC is revealed when we want to alter the behavior of a control system. Since the PLC is a programmable device, we can alter its behavior by changing the commands we give it, without having to reconfigure the electrical components connected to it. For example, suppose we wanted to make this switch-and-lamp circuit function in an inverted fashion: push the button to make the lamp turn off, and release it to make it turn on. The "hardware" solution would require that a normally-closed pushbutton switch be substituted for the normally-open switch currently in place. The "software" solution is much easier: just alter the program so that contact X1 is normally-closed rather than normally-open.
In the following illustration, we have the altered system shown in the state where the pushbutton is unactuated (not being pressed): In this next illustration, the switch is shown actuated (pressed): One of the advantages of implementing logical control in software rather than in hardware is that input signals can be re-used as many times in the program as is necessary. For example, take the following circuit and program, designed to energize the lamp if at least two of the three pushbutton switches are simultaneously actuated: To build an equivalent circuit using electromechanical relays, three relays with two normally-open contacts each would have to be used, to provide two contacts per input switch. Using a PLC, however, we can program as many contacts as we wish for each "X" input without adding additional hardware, since each input and each output is nothing more than a single bit in the PLC's digital memory (either 0 or 1), and can be recalled as many times as necessary. Furthermore, since each output in the PLC is nothing more than a bit in its memory as well, we can assign contacts in a PLC program "actuated" by an output (Y) status. Take for instance this next system, a motor start-stop control circuit: The pushbutton switch connected to input X1 serves as the "Start" switch, while the switch connected to input X2 serves as the "Stop." Another contact in the program, named Y1, uses the output coil status as a seal-in contact, directly, so that the motor contactor will continue to be energized after the "Start" pushbutton switch is released. You can see the normally-closed contact X2 appear in a colored block, showing that it is in a closed ("electrically conducting") state. If we were to press the "Start" button, input X1 would energize, thus "closing" the X1 contact in the program, sending "power" to the Y1 "coil," energizing the Y1 output and applying 120 volt AC power to the real motor contactor coil. The parallel Y1 contact will also "close," thus latching the "circuit" in an energized state: Now, if we release the "Start" pushbutton, the normally-open X1 "contact" will return to its "open" state, but the motor will continue to run because the Y1 seal-in "contact" continues to provide "continuity" to "power" coil Y1, thus keeping the Y1 output energized:
To stop the motor, we must momentarily press the "Stop" pushbutton, which will energize the X2 input and "open" the normally-closed "contact," breaking continuity to the Y1 "coil:"
When the "Stop" pushbutton is released, input X2 will de-energize, returning "contact" X2 to its normal, "closed" state. The motor, however, will not start again until the "Start" pushbutton is actuated, because the "seal-in" of Y1 has been lost: In addition to input (X) and output (Y) program elements, PLCs provide "internal" coils and contacts with no intrinsic connection to the outside world. These are used much the same as "control relays" (CR1, CR2, etc.) are used in standard relay circuits: to provide logic signal inversion when necessary.
To demonstrate how one of these "internal" relays might be used, consider the following example circuit and program, designed to emulate the function of a three-input NAND gate. Since PLC program elements are typically designed by single letters, I will call the internal control relay "C1" rather than "CR1" as would be customary in a relay control circuit:
In this circuit, the lamp will remain lit so long as any of the pushbuttons remain unactuated (unpressed). To make the lamp turn off, we will have to actuate (press) all three switches, like this: This section on programmable logic controllers illustrates just a small sample of their capabilities. As computers, PLCs can perform timing functions (for the equivalent of time-delay relays), drum sequencing, and other advanced functions with far greater accuracy and reliability than what is possible using electromechanical logic devices. Most PLCs have the capacity for far more than six inputs and six outputs. The following photograph shows several input and output modules of a single Allen-Bradley PLC. With each module having sixteen "points" of either input or output, this PLC has the ability to monitor and control dozens of devices. Fit into a control cabinet, a PLC takes up little room, especially considering the equivalent space that would be needed by electromechanical relays to perform the same functions: One advantage of PLCs that simply cannot be duplicated by electromechanical relays is remote monitoring and control via digital computer networks. Because a PLC is nothing more than a special-purpose digital computer, it has the ability to communicate with other computers rather easily. The following photograph shows a personal computer displaying a graphic image of a real liquid-level process (a pumping, or "lift," station for a municipal wastewater treatment system) controlled by a PLC. The actual pumping station is located miles away from the personal computer display:


Use for the Civil Engineering Field

As for the brief discussion of the PLC (Programmable Logic Circuit) this is now applicable in many construction Fields for example the Theater controls on which in the construction proper Civil engineers Tends to integrate the technology towards the structural Design, thus, each and every movement of the system of the machine will be timed and of course accurate enough in right timing and much safer for human.


RECOMMENDATION:
As a civil engineering practitioner I would highly recommend that the study of the system be use and carefully study by the future engineers for this is a powerful tool waiting to be developed by the CE Pratctitioner

FEATI University, Science and Technology Expo 2005

Substitute for Epoxy Concrete Crack Injection
(Best Department Entry, FEATI University, Science and Technology Expo 2005)
By
Mr. Moniel Santos (Researcher)

Engr Alex H. Balaan (Adviser)

The most commonly used seen in a vertical structure are the so-called hairline cracks. These cracks maybe found in beam, column and walls due to cement settings, additional loading and low seismic activities or tremors. These can cause exposure of reinforcing steel bars in the atmosphere which may produce an oxidation reaction which may later on turn into rust. The cement may also expand and become hallow which can cause serious damages the structure.
The most popular material used nowadays to seal the cracks and prevent exposures of reinforcing steel bars is the epoxy crack injection. When the said injection is applied, it hardens the structure with a nominal strength equal to a concrete w/c is 300 psi. however, this procedure is quite very costly.
Therefore, the researcher find an alternative substances which has the same productive effect, but nonetheless, economical. Studies show that in the old time, people used a strong liquid adhesive that came from animal skins and interterm based on this observation, the researcher put into test a solids form mixture of protein based carabao skin and added water. It eventually blended and resulted into a viscous liquid state similar to oil.
The researcher moved on to another widely used glue which is the pearl glue. It is also an animal based protein. The researcher added water, bring it to a certain boiling temperature and set aside. It exhibited an elastic properly as hard as the first substance, but much stronger than the previous one. However, it cannot be injected due to its viscosity. The workability is low and when diluted, it loses its strength. It also took a longer time to dry.
To become up with our desired goals, the researcher decided to combine the two mixture in a certain proportion and performed the same procedures with precise measurement and exact temperatures. The resulting mixture exhibited or well-defined liquid state. The workability is good. Furthermore, when it was set aside, it become hard which maybe similar to a concrete. However, to make it workable, it should be noted that exact measurements must be observed from cooling, otherwise, it will become viscous and later on, will only become a glue. If set aside, it will be hardened and if reused, it will be weaken.

Reference: FEATI University Science and Technology Expo 2005 Souvenir Program

Tagged : FEATI University, College of Engineering, Civil Engg. Dept.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT

Title : “Polymer Fiber: A Potential Admixture of Cement for Concrete

Mixes"

Researchers : Glen F. Calatrava, Merlito L. de Luna and Ma. Milagrosa L. Tarrayo

Adviser : Engr. Elizabeth R. Rivera

School : FEATI University

Date : March 2005

Degree : Bachelor of Science in Civil Engineering

This study covers the experimentation of adding polymer fiber into the concrete mix before mixing. Mix proportion used was with respect to the cement’s percent by weight in kg being an admixture only. The experiment consists of eighteen specimens: five experimental groups with varying proportions of polymer fiber to cement and a standard mix having no polymer fiber, each being poured and molded in three cylinders for different curing ages. Testing the specimens is classified according to the curing age of the concrete as on the seventh, fourteenth and twenty-eighth days.
This polymer concrete is applicable to specific structural members such as slab overlay, asphalt overlay, or bridges being subjected to heavy moving loads
This study has been made to determine the possibility of using polymer fiber as a potential admixture of cement in a concrete. Also, to further analyze polymer fiber and it’s various structural applications that would greatly contribute to the construction industry. The experiment made was formed by mixing dissolved polymer fiber (polyvinyl alcohol, pva) into the cement, sand, and gravel at 1:2:4 mix proportion of class “A”. The polymer fiber being added into the concrete mix has five different proportions ranging from 2% to 10% with respect to the cement’s weight in kg. These concrete mixes were molded in a cylinder, and then cured for seven, fourteen and twenty-eight days. After curing at specified days, the specimens were subjected to compressive strength test with the use of the hydraulic press. Based on the compressive strength test results, the specimens were noted that polymer fiber mix gives better strength than the standard mix up to 50% at the proportion 6% to 94%, polymer fiber to cement, respectively. It has also been found and observed that the greater the polymer fiber, the more viscous is the mix, which makes it non-workable to mix.

SUMMARY OF FINDINGS AND CONCLUSION
On the basis of the compressive strength test results and physical observations, the conclusion that, it is possible to add polymer fiber (polyvinyl chloride) as a cement admixture for concrete mixes showing greater strengths over the standard mix have been made.
Besides, it gives the following consequences:
The proportion 2% of polymer fiber & 98% of cement by weights gave the highest compressive strength results while proportion 6% of polymer fiber & 94% of cement gave equal strength to the standard mix. Polymer fiber being added to the cement as an admixture gave efficient characteristic on the performance of the concrete with respect to its properties as to better strength, durability, elasticity and shrinkage. Concrete may adopt the plastic’s property in terms of elasticity itself. Giving higher strength results, which tend the concrete to deform but would certainly return to its original shape as unloaded.

RECOMMENDATION
The experiments performed in this study were primarily designed to get the relative advantages and disadvantages of the polymer fiber over the standard mix specimens. For further study, the following recommendations are given Polymer fiber to be added to the concrete mix must be based on the constant volume of cement, sand and gravel at certain mix proportion, so that greater strengths may be reached. Aggregates to be used should be analyzed first with respect to its properties as to grain size analysis, fineness modulus, specific gravity, and moisture content in order to produce more accurate concrete mixes. Additional tests such as splitting tensile strength, flexural strength and shrinkage crack mitigation should also be performed for more evidences of comparison for the experiment. Specimens should also be weighed so as to compare polymer fiber mix over standard mix to further prove plastic’s lightweight property.