FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT

Title : “SPRAYABLE CEMENT-BASED COMPOSITES FOR SEWER REPAIR”

Researchers : BRIAN BAILEY K. ARQUERO, VALENTINO AQUINO, MELBORNE M.

BOSTON, FELIX B. CERDA and RICHARD S. USI

Adviser : Prof. Gerard V. Paguibitan

School : FEATI University

Date : March 2007

Degree : Bachelor of Science in Civil Engineering

A sprayed-on phosphate cement coating formed from the combination and reaction of a phosphoric acid solution and a base metal solution. The acid solution and base solution may be intermixed prior to spraying, during spraying, or on a substrate. The curing reaction rate of the phosphate cement coating and its final physical properties may be controlled by adding various retardants, accelerants, reducers, wetting agents, superplasticizers, buffers, water reducers, adhesive agents, hardening agents, and/or sequestrates to the precursor solutions. The curing rate and properties of the cement coating may be further controlled by adjusting the temperature of the precursor solutions and/or the target substrate


SUMMARY OF FINDINGS
The present invention relates to a sprayable phosphate cement material with a controlled curing reaction time and viscosity. The cement composition includes a phosphoric acid component, a metallic alkali or base component, and water. The phosphoric acid component and the metallic base component are mixed with water separately to form component slurries (i.e., an acid slurry and a base slurry), and each slurry is maintained separately until the application step. The acid and base slurries may each be thought of a first and/or second precursor constituent of the phosphate cement composition. Depending upon the order of usage either could be the first or second constituent. The application step preferentially involves first coating a desired surface with the phosphoric acid mixture and then with the metallic base slurry. Alternately, the application step may involve first coating the desired surface with the base slurry and then the phosphoric acid solution, or simultaneously spraying the desired surface with the both the phosphoric acid solution and the base slurry from separate sources, wherein the acid and base components mix in transit or in situ on the desired surface.
Preferentially water, metallic base and one or more retardants, emulsifiers, deflocculates, sequestrates and/or dispersants are added to cold water and mixed in with the silica source(s) to form a slurry. Next, the liquid phosphoric acid or phosphate salts are quickly mixed into the slurry, and the slurry is then preferably immediately sprayed onto a desired target, although the use of cold precursors and strong retarders can extend the shelf-life of the mixed phosphate cement slurry such that immediate spraying is not a requirement. Alternately, with the use of strong retardant additives, dry powder phosphate salts, silica sources, and metallic oxide alkali powders can be mixed together to form a slurry having a long enough shelf-life to make spraying possible.
After the phosphoric acid and the metallic base components are mixed, the phosphate cement slurry is preferably used promptly. The individual cement components may be mixed in spray cans or any clean containers and mixed right on the job, preferably in a cool environment. Preferably, the water used in the mixture is added cold in order to retard the progression of the exothermic acid-base phosphate cement-forming reaction.
Alternately, the phosphoric acid and/or the base coat may be brushed on, with the other coat also either sprayed or brushed on. One coat of the slurry with acid and base and silica sources is usually enough to provide good coverage, although subsequent coats are easy to apply and may be applied immediately after the first coat is applied. In the preferred embodiment, the phosphoric acid coating is applied first. More preferably, the phosphoric acid coat contains a silica source admixed therein. Alternatively, the base coating is applied, preferably by spraying, such that it penetrates the existing phosphoric acid layer and allows the cementitious reaction to begin. The reaction progresses rapidly since the reactants are spread as a thin coating over a large surface area. Also, the heat generated by the reaction is dissipated quickly, again because the reaction occurs over a large area and is generated in a thinly spread film having a very high surface area to volume ratio. In an alternate embodiment, the base coat is applied first, followed by the phosphoric acid coat, thereby catalyzing the in-place base slurry.Some preferred phosphoric acid components include potassium phosphate, magnesium phosphate, sodium phosphate, aluminum phosphate, ammonium phosphate, iron phosphate, zinc phosphate and combinations thereof. By using controlled combinations of different phosphate salts, each one spiking in temperature at a different time, the overall temperature profile of the composition is controlled so as to substantially minimize the maximum temperature reached. Therefore, the controlled combination of the above-listed phosphate salts has the same effect as the addition of a temperature retarder. In addition the resultant mix of different shaped and size crystals can yield denser packing and gives a "granite effect" to a composition formed has improved fracture strength as cracks cannot as easily propagate through a composition with no
common cleavage lines. The phosphoric acid component may be either a solid (preferably a powder) or a liquid. Some preferred metallic base components include magnesium oxide, dolomite, zinc oxide, aluminum oxide, potash, calcium oxide, lithium carbonate, barium carbonate, molybdenum oxide, calcium hydroxide, aluminum hydroxide, tin oxide, nickel oxide, magnesium hydroxide, iron oxide, titanium oxide, dolomite, manganese oxide, and zirconium oxide, zirconium hydroxide and wood ash. One means of controlling the reaction rate of the cement is by controlling the temperatures of the cement components. The colder one or both of the components are kept, the slower the reaction progresses. One way of controlling the temperature of the phosphoric acid component and the metallic base component is by cooling the water used in the admixture of each. Another means of temperature control is cooling one or both of the components' containers and/or the spraying apparatus; such is in an ice bath or by refrigeration. Another means of controlling the reaction rate is to keep the surface to be sprayed cold, such as with ice or cold water or dry ice. Various combinations of these cooling techniques may be employed to obtain maximum temperature control of the reaction.
Another means of controlling the reaction rate is the use of the retarders (surfactants, retarders, dispersants, water reducers, super plasticizers, and sequestrates) in the cement-forming components. Preferably, the retarders are added to the water before it is added to the powdered phosphoric acid solution and/or the metallic base precursors (minerals, metal oxides, and the like) to form the base slurry. This approach provides that no water contacts the component materials (usually powders) without a dispersant/retarders present. Since cement-forming powders are reactive, the retarders slow the setting time by keeping them apart, eliminating or reducing rapid agglomeration and aiding to control the reaction of the cement.
Another embodiment of this technology contemplates pre-mixing the phosphoric acid solution and the metallic base slurry before spraying. In this embodiment, it becomes necessary to reduce the reaction rate of the cement sufficiently to keep the mixed cement slurry from becoming too viscous to remain sprayable as a thin coating. This is achieved through cooling the mixed solution, by using chilled water and/or refrigeration of the container and sprayer and/or through the use of retarders. Retarders are used to keep the component particles dispersed in order to slow the chemical reaction and prevent agglomerations from forming inside the sprayer. Another method of controlling the speed of the phosphate cement-forming reaction is through the use of pH buffers to regulate the pH of the solution and thereby its reaction rate. Yet another means of regulating the reaction rate is by controlling the concentration of the acid and base components or, conversely, the water component. Increasing the water concentration will slow the reaction rate of the cement. Traditionally phosphate cement manufacturers want a low water/cement ratio as they believe that like Portland cement, the lower the w/c ratio the greater the compressive strength. Through the addition of more mix water, the crystals continue to grow/form as long as there is unreacted acid

CONCLUSION
It is preferred that the phosphate cement be mixed thoroughly. If even stronger and less porous cement is desired, it is more preferred that a plastic resin and/or catalyst/initiator be admixed therein to yield strong phosphate cement that’s less porous and more water resistant. The additions of MMA (methyl methacrylate), EMA (ethyl methacrylate), BMA (butyl methyl methacrylate) and other epoxies, urethanes and plastics can also yield harder or tougher cements. Moreover, the addition of an emulsifier helps to better disperse the above additives in the cementitious mixture. Phosphate cements cure exothermically, generating substantial amounts of heat quickly. The heat generated by the curing phosphate cement likewise speeds the curing of endothermic plastics and plastic coatings, such as 2 part epoxies. Additionally, the heat generated by the curing phosphate cements is often sufficient to raise the energy of a system containing an exothermically curing component enough to initiate the reaction (in other words, if the system includes a component that requires an predetermined energy influx in order to begin reacting, the heat spike produced by the curing phosphate cement usually exceeds the predetermined energy influx requirement). phate cements are compatible with catalysts such as BPO.

RECOMMENDATION
It is preferred that the sprayed surface first be cleaned in order to optimize the bonding of the reactive phosphate cement. It is not necessary to abrade or acid etch a surface in preparation for cement spraying, although a wash with phosphoric acid (or other acids) or NaOH or KOH solutions does tend to enhance bonding. Other cementitious or plastic based products for overlaying concrete require that the concrete surface first be cleaned and then either etched or abraded. A smooth surface finish may be produced by limiting the size and/or amount of the aggregate component of the cement. Also, the additions of diatomaceous earth or potassium silicates, fumed silica, colloidal silica, silica flour or the like may improve the surface finish without substantially diminishing the cement's strength or chemical stability. The aforementioned clays and diatomaceous earth and combinations thereof retard the initial setting or curing of the phosphate cement, as well as enhancing the flow ability and workability of the cement (i.e., producing cement that is self-leveling and self-consolidating). Diatomaceous earth and/or bentonite additions (preferably at levels of about 0.1 to 4%) may be thoroughly mixed into the cement precursor to achieve the result of reducing the number and size of surface pores. Likewise, the surface finish may be controlled by the additions of dispersants and/or sequestrates that control the distribution of the aggregates
in the mix.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT

Title : “USING ABACA TO STRENGTHEN THE QUALITY OF THE

GLUE USED FOR REPAIRING CONCRETE CRACKS”


Researchers : IAN OSBORNE CANEDO and LAURENCE ESTILLORE

Adviser : Dr. Tomas U. Ganiron Jr

School : FEATI University

Date : March 2007

Degree : Bachelor of Science in Civil Engineering


Reinforced concrete slabs have been widely used in modern transportation engineering, such as highway and airport pavements and bridge decks. Cracking in slabs reduces the local capacity and has been linked to fatigue failure in addition; cracks allow water and other chemical agents, such as deicing salt, to go through the cover layer to come into contact with the reinforcements, loading to reinforcement corrosion and rupture. Concrete shrinkage and temperature changes are the principal reasons for the initial crack formation and preparation afterward in slabs. Therefore, in order to prolong the service life of concrete pavements and bridge decks, shrinkage and temperature induced cracks using abaca strips to strengthen the quality of the glue in concrete pavements and bridge decks, cracking in concrete due to shrinkage and temperature changes can be avoided. Moreover, cracks, especially shrinkage and temperature cracks are localized into designated strips, where abaca material with tensile strain-hardening and high strain capacity is used. As a result, while microstructure damage exists in the abaca strip, the concrete remains intact.
Due to the special material properties of the abaca material, the strain energy produced by shrinkage of hardened cement and temperature changes can be released by the high strain ability material so that cracking in plain concrete can be avoided. By replacing standard joints in concrete pavements, common deterioration problems associated with joints will be eliminated. A possible abaca strip is a fiber reinforced engineered cementations composite (ECC).

SUMMARY OF FINDINGS
The tensile specimens were tested at 7 days and 28 days after casting, respectively. The test procedure was the same as that used for the tensile test on plain concrete. From the results, the researchers for the specimen cured only for 7 days, the specimen failed in a brittle manner even though the first crack already occurred in the abaca strip in one of the two specimens. However, the final failure occurred in the concrete section of this specimen. This is expected, since at 7 days curing the first crack strength of abaca strips and the tensile strength of plain concrete are very close;. Therefore, even if the first cracking occurs in the abaca strip, as load increases, the stress in the concrete section may reach the concrete tensile strength, resulting in failure in the concrete section instead of further development of new cracks in the abaca strip. For the specimen cured for 28 days, the situation is totally different
In this case, the concrete tensile strength is much higher than the first crack strength of ECC and even higher than the ultimate tensile strength of ECC. Therefore, as the specimen is loaded in tension, first cracking will occur in the abaca strip and multiple cracking can be developed in it due to sufficient difference between the ultimate tensile strengths of ECC and concrete. Cracking with crack widths less than 0.1 mm was successfully localized into the abaca strip instead of in the concrete section. This is the final goal of the present investigation. Furthermore, in the present dimension of the specimen, the strain attained 1.4% at peak load 3.5 MPa.

CONCLUSION
This research presents an experimental study on the potential applications of abaca engineered cementations composite in continuously steel reinforced concrete slabs, such as concrete bridge decks and pavement, for the purpose of eliminating cracks in concrete. It is found that a composite slab containing both plain concrete and abaca strips, with proper design at the ECC/concrete interfaces and careful selection of material properties to as-sure that the tensile strength of concrete higher than that of ECC material.. It is possible to localize tensile cracks into the abaca strip instead of in the concrete section. The current concrete mix satisfies the above condition after 14 days of water curing. Due to the strain-hardening performance of the ECC material with a high strain capacity up to 5%as well as a high fatigue crack resistance behavior, the overall strain capacity and the integrity as well as the fatigue durability of the composite slab can be significantly improved. In the present study, the overall strain capacity of the test specimen achieves 1.4% at peak load.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT

Title : “RECYCLED BROKEN GLASS AS SUBSTITUTE FOR COARSE

AGGREGATE TOWARDS DESIGNING A CONCRETE

MIXTURE"

Researchers : MELBORNE M. BOSTON, FELIX B. CERDA and RICHARD S. USI

Adviser : Prof. Gerard V. Paguibitan

School : FEATI University

Date : March 2007

Degree : Bachelor of Science in Civil Engineering

The Philippine today is on the front line of pursuing its economical, social and political, programs. Parallel to these matters, the national consciousness of the individual must be strengthening.
Rejected broken glass a substitute for coarse aggregates by percentage is capable of strengthening and infusing this equipment among the student to pursue doing some experiment to discover new materials in mixing concrete and also lessen the wastage of glass, instead of throwing it into the garbage we can used it as a materials in concrete mixing.
However the purpose of this study is to describe potential of glass in terms of strengthening concrete structures and to minimize the percent amount of gravel used in the construction. This study describes some important uses to consider and develops a model for cost estimating.
The value of substituting recycled glass for low price virgin raw materials in container manufacturing has always placed in an upper limit on the value of collected recycled glass. Increasing, however, a researcher is being performed to asses that availability of processing glass to gravel size for marketing as a raw materials in traditional industrial materials application.

SUMMARY OF FINDINGS
Based upon the results of the compressive test, the broken glass aggregate gradually diminished as the percentage of the broken glass increases. A five (5) percent inclusion of broken glass to the concrete mixture gives a compressive strength that complies with the standard compressive strength for wall panel and gives a higher compressive strength than the sample concrete without broken glass.
The laboratory trial batches are used as the basis for selecting concrete proportion and compressive strength test are made in accordance with Method of Tests of Compressive Strength Tests (ASTM C-39 93a) on cylinders prepared in accordance with method of making curing tests specimen in the laboratory (ASTM C-192 93a).
The findings showed that broken glass can be use more than 15% weight of coarse aggregates in preparation in concrete mixes.


CONCLUSION
Alternative materials referred to, as a broken glass can be use 10% weight of coarse aggregates in preparation in concrete mixes. This showed that the required compressive strength satisfied as indicated on the tests results from DPWH-NCR.
The effect of broken glass to the concrete mixture is that an increase of more than five percent insertion by weight to the concrete mixture compromises the compressive strength of the concrete. Therefore a mix design of five percent weight insertion to the concrete mixture gives a desirable result in terms of its compressive strength.


RECOMMENDATION
Based on the stated conclusions, the researchers propose the following recommendations:
1. A derivation of equations on the flexural and compressive strength using different

types of broken glass mixture.

2. A testing of more concrete specimens with broken glass specimen and plain concrete

to achieve ideal good results.

3. Provide an apparatus that will break down the glasses to a desirable concrete mix

size

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT

Title : “UTILIZATION OF THERMOPLASTIC AS A
SUBSTITUTE TO FINE AGGREGATE TO CONCRETE CEMENT
FOR ROW HOUSE WALL PANEL”

Researchers : ROCHELLE M. ERFE, MICHAEL VINCENT V. VALITE and
JESUS B. TONGA

Adviser : Dr. Tomas U. Ganiron Jr

School : FEATI University

Date : March 2007

Degree : Bachelor of Science in Civil Engineering

The main purpose of this research is to analyze the effectiveness of thermoplastic
when added to concrete cement. Also to address the needs of the ecological sector in terms of recycling the waste plastic that harms not only the soil structure and the environment as per say but as well as the human who without their knowledge damage their health because of the degradation of this product.
The plastic was grounded into pieces for concrete mixture, where it substitutes the 5% of the fine aggregate, which is the sand. It then undergoes to strength test that investigate whether it can pass or at least equal the standard specification of concrete mix for wall panel. The experimentation went through moisture content test, specific gravity test, slump test, sieve analysis, compressive test and flexural test.

SUMMARY OF FINDINGS
The experimental procedure done on the experiment was found to be adequate in terms of testing the material, thermoplastic, since all the experiment done is applicable for the concrete mixture test.
Thermoplastic as a substitute to fine aggregate to concrete mixture has shown unusual characteristic upon accumulation of water in the mixture for the material had floated on the surface of the water, nevertheless, upon the completion of mixing the material has suitably bonded to the mixture. In the analysis of its grain particle, in comparison to sand, which is one of the major components of concrete mixture, thermoplastic, imply significant lightness in terms of its mass evaluation.
Overall, the effect of the thermoplastic on the properties of the specimen was acceptable. The thermoplastic material substituting the 5% of sand, the fine aggregate of mixture managed to attain the required strength in accordance with ASTM standard C62
– 97 specification of wall panel, which is 2500 psi (17.24 MPa). On its 28th day the specimen with the thermoplastic fine aggregate attain at least 19 MPa average for both of the tested specimen, which exceeded that of the design specification.


CONCLUSION
The thermoplastic material copes up with the ASTM standard specs with no adverse effects on the properties needed by a concrete mixture for wall panels (CHB’s, bricks and mortars). It can be concluded that the positives are significant enough to justify the use of thermoplastic (Waste Plastic material) in concrete mixture. Although much to the expectation in flexural strength which failed on the 28th days curing, the research is still looking on the strength of compressive strength which is the more important characteristic of the concrete.
In conclusion, there’s a little discussion to be tackled for the use of thermoplastic waste in concrete mixture. An important consideration on this incorporation of thermoplastic waste in concrete is the development of this research in order to give the material a higher quality in order to be use in other concrete application such as beams, columns, slabs and road pavements.
Of course it is economically feasible compared to fine aggregate since the research focuses only on material that are considered waste and not the so – called ‘virgin’ plastic that can be very expensive if altered to the sand. The scrap value of the plastic would even add employment to those people living in slump areas where most waste plastic is being heaved.
In terms of heat and temperature of the thermoplastic, it is concluded that with an increase in the stretching temperature up to a definite limit (170°C) the tensile strength of PETP and other fibers from crystalline polymers increases. However, at higher temperatures (230°C) the strength diminishes. This is evidently due to a reduction in the density of the intercrystallite regions of the fibrils, in which there is greater probability of polymer failure originating. Such behavior of fiber made from PETP at elevated stretching temperatures is evidently associated both with the polymer structure and with its low molecular weight.

RECOMMENDATION
The researchers recommend that a support from government for grounding of waste plastic as alternative for fine aggregate would be develop to further enhance the technology. If the said institution can employ this kind of help, then the task for pulverizing the plastic would be much easier. They also recommend the developer to further investigate the research for upgrading the material. To further develop the technology would probably be the first step to establish this material as a construction material option in building houses using concrete.
In terms of factors affecting the quality of thermoplastic additive includes grain distribution during sieve analysis, application of standard testing, and proper mixing and proportioning of concrete mixture. Following the standard is not intended to chastise the producer but to promote good quality and thus giving the technology a chance to be noticed by the construction industry. It is also recommended to try different proportioning of thermoplastic from 2 %, 5%, 7 %, 10% up to their desired ratio. This would give more data to compare thus finding which percentage will give the better quality results. Avoidance of excessive water during mixing is also recommended and to adhere the estimated percent of mixture during the laboratory test is advised. The temperature during mixing of concrete should also be considered since the substitute is plastic. Plastic in its property can be affected by heat. For product costing the product is being suggested to those people with applicable knowledge regarding the matter since the researcher had no idea with respect to this.

FEATI UNIVERSITY-CIVIL ENGINEERING DEPARTMENT THESIS AND RESEARCH 2007

ABSTRACT


Title : COCO COIR POLYPROPYLENE (CCP): AS A THERMAL

INSULATOR

Researchers : LAURENCE ESTILLORE, MARICAR A. FRANCISCO
MONIEL C. SANTOS

Adviser : Engr. Alex H. Balaan

School : FEATI University

Date : March 2007

Degree : Bachelor of Science in Civil Engineering

Thermal insulators are essential in terms of making structures conducive for people to live in and a nice place to work on. The main objective of the research is to develop a thermal insulator using recyclable materials namely; the coco coir from the coconut fruit and used polypropylene drinking straws. The researchers were led to the assumption that all materials have a property to conduct heat and a material which has low thermal conductivity is an ideal insulator. Observing the physical properties of the coco coir being a composite material and various applications, It was incorporated, as well as the polypropylene used straws being commonly named as plastics gives an idea to the researchers to make these materials the core components of a product that can be used as a thermal insulator, thus by comparing the innovated products to an insulator that is available in local hardware stores with regards to their physical properties, could came up with a statement that CCP can be a thermal insulator.
The researchers have conducted several property performance tests, to test the effectiveness of the innovated product, such as its ability to insulate heat, its resistance to flame and its ability to absorb moisture. The researchers used the comparative method of the study and experimentation to arrive to a reliable conclusion.

SUMMARY OF FINDINGS
In the duration of the study, the researchers have observed the following outcomes of the performed property performance test experiments, comparing the performance of the two samples on the improvised heat insulation performance test, the coco coir polypropylene compared to the commercialized brand maintains a cooler temperature inside the cabin wherein the apparatus is subjected direct exposure to sunlight and that the performance of the coco coir polypropylene is with close proximity compared to that of the commercial brand.
The ability of a material to react when subjected to flame is important when factors of safety are to be considered. In the improvised flame test wherein both samples were placed simultaneously to direct flame the researchers have observed that CCP has a slower rate of flame tolerance than of the local brand.
The coco coir polypropylene is then soaked to an ample amount of water where it was left for seven experimental days to note the change of weight. It was observed to have absorption of 2% by weight on a seven day trial period.

CONCLUSION
The coconut coir and polypropylene exhibited thermal resistance value of thermal property which was vital importance. Moreover, CCP showed the innovated product has a slow rate of heat absorption and more economical considering its proponents are recycled materials proves to be a promising item for consumption.

RECOMMENDATION
The study should be given a continuous investigation in the application of the material to the construction industry. In view of the fact that there is no thermal insulation standard in our country at present the researcher is then left to the option of considering the current standards from other countries. There must be a variety of aspects that should be considered in terms of climate and weather conditions which are correlated with the design of an insulator needed for the insulation of a particular structure in a specific location. The researcher further suggested a scrutinized reckoning with regard to the economical impact it could bring to the economy considering the low-cost value of product fabrication at present. Bearing in mind the actual performance of the product to the controlled performance test with the existing thermal insulator revealed that the product has the ability to insulate heat therefore making it an adept thermal insulator.
Finally the researcher also would like to commend the quantification of the actual R-value of the product through accredited instruments, apparatuses and equipments in accordance with the pre-existing specified standards since this is the property of the utmost importance especially when it comes to the commercialization of the innovation. Recommend for more desirable binding agent.