Project management is an art entailing planning, organizing, and administering set goals. It requires the orchestration of the various aspects of deadline-based discrete projects.
A profession in project management requires working with a team of people; therefore, a successful project manager needs to understand the importance of teamwork, and how to achieve more together. Usually, a project is temporary in nature and requires a one-time effort, in order to create a distinct product or service. This demands various technical skills that can be handled efficiently by a project manager.
Encountering and overcoming challenges is a part of this profession. The basic requirement is to ensure the delivery of a project within defined time limits. The optimized allotment and combination of various inputs to meet the objective of the project is another challenge in this profession. Project managers generally work in various areas, such as computer and information systems management, engineering and management of finance. Initially, they help in the development of the range of the project, and then monitor its progress all the way. Ultimately, they gain vast experience in their field and become consultants, partners or shareholders in project management companies.
Activities Related To Project Management
Project management deals with various kinds of activities that need to be carried out effectively in order to accomplish the work within client specifications. Some of the related activities are as follows:
-Planning regarding the set objectives
-Analyzing and designing of the objectives
-Evaluating risk factors involved.
-Estimation of resources
-Organization of work
-Acquiring material and human resources
-Controlling execution of the project
-Tracking and reporting about the progress of the project
-Defining products of different projects
-Predicting future trends in the project
Efficiency has become key in almost every profession, and cost overruns and delaying of deadlines are not tolerated. Therefore, the requirement for project managers has increased rapidly. They lead and guide the team to coordinate complex projects, and accomplish their targets on time, as well as within the budget. Hence, they need certain skills:
-Excellent communication skills
-Decision making ability
that help them excel in their field of work.
Saturday, July 10, 2010
Project management is an art entailing planning, organizing, and administering set goals. It requires the orchestration of the various aspects of deadline-based discrete projects.
In the past few years the pre-cast industry has grown tremendously with the new and challenging requirements from most of the construction industry. The precast concrete elements with defects need to be repaired properly.
Repairing Minor Defects of Precast Concrete:
Defects not impairing the functional use or expected life of a Pre-cast concrete product shall be considered minor defects.
Minor defects may be repaired by any method that does not impair the product.
When honeycombed areas are to be repaired, all loose material shall be removed and the areas cut back into essentially horizontal or vertical planes to a depth at which coarse aggregate particles break under chipping rather than merely being dislodged.
Repairing Major Defects Precast Concrete:
Defects in Pre-cast concrete products that impair the functional use or the expected life of products shall be considered major defects
Repairs should be made as soon as feasible after the defect is noted so that differential shrinkage between the original concrete and the repair concrete is minimized. Repair materials used in repairs of major defects should be essentially the same as the original concrete.
The repair material should become an integral part of the product with no delaminations or cracks.
SIKA Products for Precast Concrete Repairs
Sikagard 75 Epocem
Superfine epoxy cement sealing mortar, a three component modified cementitious mortar
Sika Refit 2000
A one component polymer modified cementitious based mortar containing silica fume used for cosmetic surface repair & fair coating
Sika Monotop 615 HB
A one component thixotropic, high build, polymer modified mortar containing silica fume, used as repair mortar
Sika Monotop 610
A one component cementitious, polymer modified mortar containing silica fume and corrosion inhibitors, used as bonding slurry and reinforcement* corrosion protection
Sika Monotop R
A one component thixotropic, polymer modified fiber reinforced cementitious mortar used as repair mortar
2-component bonding agent, based on selected epoxy resins, for bonding of new to old concrete
Thixotropic 2-component adhesive and repair mortar based on combination of epoxy resins and specially selected high strength fillers for concrete repairs
Non-shrink, self levelling, pre-mixed cementitious grouting mortar
AAET ENGINEERING SCIENCE AND TECHNOLOGY COMPETITION FOR ASEAN STUDENTS
“CONCEPT DESIGN OF A GREEN HOUSE FOR LOW INCOME PEOPLE FOR A BETTER QUALITY OF LIFE AND CLIMATIC CHANGE”
The ASEAN Academy of Engineering and Technology (AAET) is a non-profit Civil Society Organisation (CSO) registered with the ASEAN Secretariat.* It focuses on the application of Engineering, Science, Technology and Innovation (ESTI) to compliment the realization of the ASEAN Economic Community through rapid integration to create a stable, prosperous, engineering and cultural value and highly competitive ASEAN.
AAET conducts various initiatives to achieve its aim.* The AAET ESTI Annual design competition is one such initiative.* ASEAN undergraduates and postgraduate students and young engineers will have to innovate, invent and think out of the box to compete with each other to be the best three ASEAN ESTI designers.
The project for the inaugural competition is to submit a “Concept Design of a ‘Green’ House for Low Income People for a Better Quality of Life and Climate Change.”
2. Rule , Regulations and Requirements of ESTI competition
2.1. The participants in the ESTI competition must be undergraduate and postgraduate students and young engineers (less than 32 years old) with certification of their Universities and or Organization, Industries and are citizen of ASEAN countries
2.2. The entries by an individual or team
2.3. Submission of entries close in August 30, 2010. The submission should be send to the National Organizing and Organizing Committees
2.4. The concept design submission should be innovated or invented project or combining existing engineering solutions in the best way
2.5. The submission of entries should fulfill all design submission guideline and requirement of organizing committee (OC) as described and explained below:
- The size is 50 square meters, the green house can be one or two floors
- The subsoil is soft clay with undraned shear strength of 30 kPa to 5 meters of depth and bellow the above depth* is dense sand layer
- Design concept with emphasis on Green aspects
- The house is suitable to prevent natural disaster and climatic change
- The house is suitable for low income people.
- Complete unit to include basic sanitary and light fittings
- Sketches and drawings with basic design computation with soft copy and hard copy
- BQ, total cost in USD and cost in USD per square meter
- Construction method
- Time of construction
- Expected economic life span
- Annual Maintenance cost
- Other aspects of merit
- CV of entries
- Gold : USD 10,000
- Silver: USD 5,000
- Bronze: USD 3,000
- Merit: USD 100.00
The winner of Gold, Silver and Bronze prizes will be invited to attend the International Energy Conference ( IEC) of AAET which will be held in Malaysia on October 29, 2010. The winners will receive the certification of AAET as “Famous innovator in ASEAN for the year 2010”. The winners will have the right to make a detail design and the green house will be constructed in selected countries of ASEAN for future development
4. Time Frame
- Broadcasting to all universities, organizations, enterprises and institutes by country will be in April 2010.
- Submission of entries to National Organizing Committee (NOC) and Organizing Committee in the end August 2010 for evaluation.
- Best 3 entries from each ASEAN country should be selected by NOC and to be submitted to Organizing Committee (OC) by mid September 2010.
- OC will selected top 3 winners by end September 2010.
- Notify and invite winners to award ceremony at IEC 2010 on 29th October 2010 in Kuala Lumpur in early October 2010.
5. Organizing Committee (OC) of AAET
Committee Chairman is Prof Dr. Nguyen Truong Tien. Committee members: one representative from each ASEAN country. The country representative is the Head of the National Organizing Committee for their respective countries
6. National Organizing Committee (NOC)
Head of National Organizing Committee :
· Brunei : Yong Hoi Sen
· Cambodia : Meas Sokhom
· Indonesia :
· Laos :
· Malaysia : Yong Hoi Sen
· Myanmar : Sein Myint
· Philippine : Lydia Tansinsin
· Singapore : Chew Yong Tian
· Thailand :
· Timor – Lester :
· Vietnam :* Prof. Dr. Le Duc Thang
The duties and responsabilities of NOC:
- The National Organizing Committee (NOC) have from 8 to 10 members, they are selected by Head of NOC. The NOC have all responsability to make the organisation of ESTI Competition in each ASEAN country, including a more detail information, time schedule, national prizes and other activities in order to meet all objective, requirement, rule and regulation of OC
- To establish the office, email, web… of NOC
- Raise some funds and ask some sponsor, to meet contest administrative expenses and merit prize of 100 USD for each accepted entry as well as the prizes of 3 winners in each ASEAN country. Excess fund to be kept for future competition
- Broadcast competition to all Universities, Organization and Industries in their country in April 2010
- Accept and evaluate entries in August and to September 15th, 2010
- Conduct the judging based on the following guide line:
· Planning and Architect of a house: 10 points
· Foundation and structure of a house: 20 points
· Materials: 10 points
· Basic sanitary and light fittings and energy: 15 points
· BQ, total cost and cost in USD per square meter: 20 points
· Construction method: 5 points
· Time of construction: 5 points
· Expected economic life span: 5 points
· Annual maintenance: 5 points
· Other merit: 5 points
- Give merit award of 100 USD to each accepted entry for judging
- Shortlist 3 entries for final judging by OC in September 2010
- Make the ceremony in each country to close National ESTI competition and to give National Award to 3 winners. The prizes of 3 national winners are decided by NOC
- To make the publication in soft or hard copy of the 9 best concept designs and send to all accepted entries and OC. It is recommended to make the publication, presentation and exhibition of the results from ESTI competion.
- Promote and find the sponsors to build up the green house in their country
7. Advisor Board
· Datuk Hong Lee Pee, President of AAET
· Ir Choo Kok Beng, Secretary General of AAET
· Ir Chitr Lilavivat,* AAET Founding Fellow
· Others members are invited. You are wellcome to write a proposals and suggestions to OC
The donors can be an individual, organisations or enterprise and the donation will be certificated and recognized by NOC and AAET. The donation will cover both competition organizing expenditures and prizes as well as to support AAET’s operation fund
AAET would like to promote and ask the kind contribution and donation from individual, enterprise and organizations
9. Supports from ASEAN Secretariat, ASEAN Governments and AFEO
AAET will ask the supports and helps from ASEAN Secretariat, ASEAN Governments and ASEAN Federation of Engineering Organizations ( AFEO) as well as from the Institution of Engineers and Professional Societies of each ASEAN country for AAET Engineering Science and Technology Innovation Competition
Contact person :
Ir Choo Kok Beng, Secretary General, AAET Founding Fellow,
Address of AAET:
Wisma Veritech, No 17A, B&C Jalan Kenari 4, Bandar Puchong Jaya, 47100 Puchong, Selangor Darul Ehsan, Malaysia
Tel: (603) 58826968, Fax: (603) 5882639, Mobile: 60123710, Email: [Only registered and activated users can see links. ]
C/c: Prof.Dr Nguyen Truong Tien, Chairman of OC, AAET Founding Fellow
Address of Organizing Committee:
No 9 Alley 44 Ham Tu Quan street, Hoan Kiem District, Hanoi, Vietnam
Tel: (84)4 38225907, Fax: (84)4 39439521,
Mobile: (84)90 340 5769, Email: [Only registered and activated users can see links. ]
The contact person will make any clarification, explanation to all participant and NOC. OC will make other announcement and send to NOC for general informations and guide line . Thank you very much for your contribution, promotion and your participation in this important event.
Ha Noi and Kuala Lumpur March 30th 2010
Datuk Hong Lee Pee, President of AAET
Ir Choo Kok Beng, Secretary General,AAET
Nguyen Truong Tien, FF of AAET, Chairman of OC
THE ENTRY FORM
· Name of individual or names of the team
· Birthday of individual and or all members of the team
· Email: Tel:
· Field of activities :
· Merits of your innovation in the concept design:
· Self evaluation of your entry, based in the* guide line of MC for judging :
· Any proposal and suggestion for future ESTI competition of AAET
Certification of University Organization or EnterpriseDate and place
Signature or Signature on behalf of the Team
Project Design Brief for 2010 ESTI Competition
The design submission shall fulfill all design guidelines and requirements as described below, and shall conform to the latest and relevant codes of practice and standard, and buildings safety and health regulations.
Design guidelines and requirements:-
1) Innovativeness and excellence in design
The concept design for the affordable house for the low income people shall preferably be innovative, and/or of new idea using the combined existing engineering solutions, technology and materials in the best way to achieve maximum economic value.
2) Design concept with emphasis on ‘Green’ aspects
The design shall be eco-friendly. The choices of using green materials, green technologies, energy and water saving utilities for the design and construction of the affordable house are encouraged, but a good and well balance between the choices and its economic and social values are preferred.
3) Project brief
- The proposed gross built up area of the house is 50 [Only registered and activated users can see links. ] with a minimum of 45[Only registered and activated users can see links. ] livable areas.
- The type of the proposed house can be detach, semi-detach, link house or terrace house, and single or double story. For the link or terrace house per row shall not exceed 70 M in length.
- The subsoil is soft clay with un-drained shear strength of 15 KPa down to a depth of 5 meters and below which is underlain by a thick dense sand layer of SPT value N>50.
- Where natural disasters such as typhoon, torrential rain and earth quakes are prevalent, the design must take into the consideration of the forces or loads from the natural disasters.
- The proposed house shall complete with basic sanitary, water and light fittings.
- The proposed house is for a family of 2 adults and 3-4 children, and for low income families in less developed rural areas in ASEAN member countries.
- The design submission shall complete with Concept of Design, Sketches, Drawings, Basic Design computation, estimated Bills of Quantity, Cost of Construction per house in USD as well as Cost per meter square in USD, Method and estimated Time of Construction, expected Economic Life Span and its annual Maintenance Cost, and highlight the merits and excellences in the design.
THE 30th ANNIVERSARY OF VSSMGE AND THE VIETNAMESE GEOTECHNICAL DAY CELEBRATION ON 18th JUNE 2010
Please accept our heartiest congratulations on the occasion of the 30th Anniversary of VSSMGE and the Vietnamese Geotechnical Day celebration on 18 June 2010.
The Association of Geotechnical Societies in Southeast Asia (AGSSEA) was inaugurated on 5 December 2007 to promote co-operation among geotechnical societies in Southeast Asia for the advancement of knowledge in geotechnical engineering. AGSSEA was initiated by the Southeast Asian Geotechnical Society (SEAGS) and VSSMGE was the first country member of AGGSEA. For this, I would like to say thank you to Prof. Tien.
The innovative engineers and the technical excellence in Vietnam that we are celebrating in this very special occasion emerged from the vision of a great leader. Even through difficult economic times, Prof. Tien found a way to plan and build a bright future for the Vietnamese geotechnical fraternity. His commitment to the goals of excellence is based on more than 30 years of progress supported by many dedicated people of VSSMGE who are determined to move forward.
AGSSEA is excited about the work of VSSMGE. We are excited about forming closer and closer partnership and co-operation with VSSMGE. We are committed to move forward to the next 30 years and beyond with VSSMGE. As they said “Getting something done is an accomplishment; getting something done right is an achievement”.
Once again, we extend our sincere congratulations to the achievement of VSSMGE and in particular to Prof. Tien for his invaluable contribution to the society.
Sincere best wishes,
Hon. Secretary-General, AGSSEA
Application Of Floor Hardener On Fresh Concrete Slab
Description of floor hardener
Sikafloor chapdur is a floor hardener mechanically applied onto surface of concrete slab before final setting has taken place to increase the abrasion and mechanical impact resistance of the floor.
Sikafloor chapdur is composed of non metallic very hard granular material, pigment and portland cement.
Application of Floor Hardener of Sika Chapdur
Wetting out and consolidation
Broadcast the sikafloor chapdur onto substrate before final setting has taken place.
Allow the sikafloor chapdur to absorb moisture from the substrate and when evenly moist, power float the sikafloor chapdur into the surface to consolidate.
As soon as the mixture shows uniformity and becomes plastic carry out the pre-smoothening operation using the power float fitted with metal blades at a minimum inclination and low speed.
The final smoothening operation (if necessary) should be carried out later with the power float running at high speed.
The sikafloor chapdur mixture surface must be protected to prevent rapid water loss, which may results cracks.* Therefore approved curing system must be applied.* Please consult our technical department.
Contraction joint must be sawed cut max. 24 hours after finishing smoothening work.
System : Sika Flooring Materials
Item Description/TypeTheoretical consumptionSikafloor Chapdur
(mini 3.5 kg/m2 for red, green colour)
If you are a civil engineer applying for a job in construction chemicals, this kind of recruitment test you may face during your job interview.
Case 1: Assuming you are a civil engineer working for a worldwide leader construction chemicals supplier as a senior engineer with 2 staffs under your management, you are designed to follow a project actively. The project, a 1.5km-long bridge with estimated cost of USD 100 million, is such an important project of the city that each decision, e.g: decision of raw material choice, involves many people. The difficulty you face is that the main construction company of the project seems to prefer your competitors’ products to yours. Write down your action plan to win the project in the case (who you need to meet, how to persuade them, how to assign your staff, what support you need from other departments of your company, etc.)
Case 2: Assuming you are a technical manager of an admixture company (a worldwide leader construction chemicals supplier). You are now in charge of one bridge project that your company is supplying products. One day, some break-down happens to the project: concrete compressive strength with Sika admixture is not as high as requirement. The construction company blames your company’s products even though your admixture is not the unique element influencing on concrete strength. The problem is serious because the demand of admixture of the project is still big and this construction company will participate into other projects. If you loose this project, not only will our sales volume be affected much but also our reputation on technical aspect will be damaged. As a technical engineer, what should you do in this situation?
Case 3: Before applying a chemical product to a project, a trial test must be done in a certified laboratory. You are assumed to be a technical engineer of Admixture Company and in charge of doing this test. The test is a decisive factor for your admixture to access the project. However, the test you do is not successful. After searching for causes, you find out the most probable cause is that the quality of cement is not stable. You decide to write a memo to the chief of your company’s laboratory to report the case, propose some solutions and ask for help. Please wrire down the memo (around 200 words).
Every week, we introduce some top articles in civil engineering and construction career.
1. From Civil Engineer Website:
[Only registered and activated users can see links. ]
Lightweight concrete is mainly used as back-filling material. When talking about lightweight concrete, we refer to a concrete of which its specific gravity (density) is much more lower than normal concrete…
[Only registered and activated users can see links. ]
In order to delay these detrimental effects, high durability, chloride and sulphate resistant concrete become a necessity in constructing marine structure. The use of silica fume* with a high water reducing admixture with retarding effect then become increasingly popular to produce a low permeability concrete and high sulphate resistant concrete….
2. From Civil Engineer Blog:
[Only registered and activated users can see links. ]
Generally, the contractor shall allow for all necessary measures to monitor and avoid cracking in fresh hydrating concrete, regardless the size or volume of the pour. Such measures shall be to the satisfaction of the Engineer and shall be such that maximum surface crack width on hardened concrete measure immediately after the pour does not exceed 0.004 times the nominal cover of the main reinforcement…
[Only registered and activated users can see links. ]
Sikagard 680 S Betoncolor is a one part solvent containing coating, based on methacrylic resins resistant to weathering, alkalis and ageing.
It’s available in clear and coloured grades for use on mineral substrates including concrete and other cementitious surfaces
Sikagard 680 S Betoncolor protects concrete against aggressive atmospheric influences and promotes a self-cleaning effect on the treated surfaces. It does not adversely influence the characteristic texture of the concrete.
Sikagard 680 S Betoncolor complies with the requirements of EN 1504-2 as protective coating…
More articles to be updated soon. Please visit back Construction English for more posts.
Scope of work
Application of curing compound onto fresh concrete surface
General purpose of curing compounds for fresh concrete
• To form a film covering the surface of concrete to prevent premature water loss due to evaporation
• Allow the concrete to cure with complete hydration of cement and achieve maximum properties.
Materials available for concrete curing
Emulsified paraffin based curing compound.
Ready to use
Very effective particularly on horizontal surfaces even subject to windy and sunny conditions
Shall be removed prior application of subsequent surface treatment
Aqueous concrete curing silicate solution
Ready to use
Particularly used for the treatment of vertical concrete surface
Does not impair adhesion of subsequent treatments to concrete surface (when applied within recommended dosage rates)
Compound* Application procedure
Please consult our product technical data sheets for full application recommendations.
Applicable by spray.
Typical Consumption rate: 0.2 to 0.25 litre of Antisol E or Antisol S per m2.
Protect fresh coat from rain
Regarding material viewpoint, concrete itself could be described as a mixture of sand, cement, aggregate, water, admixture and air. Practically speaking, concrete consists a lot of inter-depend task. The basic way to achieve this target is to produce concrete with low water cement ration (W/C).
The use of plasticizer or superplasticiser will allow producing concrete with low W/C by still maintaining suitable workability. Water reducers or high range water reducing and set retarding admixture have been used worldwide in this matter. Sometime due to very high solid content of the water flowing into the structure, it is requested to produce concrete that provide excellent abrasion resistance. In this case the use of silica fume will be recommended. Other benefits when using silica fume are production of watertight, durable, high strength concrete. High strength development will be achieved by using a ultra water reducer.
Seeing that high quality concrete is one of the main requirements from each designer, it will be necessary to keep this objective during all concrete production process. This concept will start by spraying mold release agent* on the formwork surface prior to pour concrete. When concrete has been produced using admixtures cited above, it will be necessary to cure it properly. Antisol range – curing compound – grouping different chemical base will allow protecting concrete from pre water lost and therefore limiting cracks.
More details on concrete production for hydro-power plants will be discussed on next post. More helpful information can be also found on
The Uses of Solar Energy in the US
Uses of Solar Energy
Solar energy has many uses. It can be used to provide heat, light or to generate electricity. Passive [Only registered and activated users can see links. ] refers to the collection of heat and light; passive solar design, for instance, uses the sun’s energy to make homes and buildings more energy-efficient by eliminating the need for day-time lighting and reducing the amount of energy needed for heating and cooling. Active solar energy refers to storing and converting this energy for other uses, either as photovoltaic (PV) electricity or thermal energy.
The uses of solar power in some States of the US
Texas, due to its large size and abundant sunshine, has the largest solar energy resources among the states. Several other states, however, lead the nation in terms of using solar energy, mostly due to state policies and incentives that encourage the installation of solar energy systems.
California is the nation’s largest solar energy market by far, and has eff ective state initiatives promoting the industry. Other states with notable markets for solar energy include New Jersey, Arizona, Colorado and New York. Even so, in 2006 solar energy accounted for just 0.01 percent of all U.S. electricity, mainly because of its higher costs compared to other power options.
Solar energy plays an even smaller role in the Texas electricity market. Still, Texas has the sunshine, manufacturing base and research institutions needed to become a leader in the development of solar energy. The state is well positioned to compete with other states and countries in a global solar energy market worth $10.6 billion in 2006.
One study estimates that Texas could capture about 13 percent of all new jobs and investments related to solar photovoltaic technologies by 2015, primarily in manufacturing.
Humans have harnessed the power of the sun for millennia. In the fifth century B.C., the Greeks took advantage of passive solar energy by designing their homes to capture the sun’s heat during the winter. Later, the Romans improved on solar architecture by covering south-facing windows with clear materials such as mica or glass, preventing the escape of solar heat captured during the day.
In the 1760s, Horace de Saussure built an insulated rectangular box with a glass cover that became the prototype for solar collectors used to heat water. The first commercial solar water heaters were sold in the U.S. in the late 1890s, and such devices continue to be used for pool and other water heating.
In the late 19th century, inventors and entrepreneurs in Europe and the U.S. developed solar energy technology that would form the basis of modern designs. Among the best known of these inventors are August Mouchet and William Adams. Mouchet constructed the first solar-powered steam engine. William Adams used mirrors and the sun to power a steam engine, a technology now used in solarpower towers. He also discovered that the element selenium produces electricity when exposed to light.
In 1954, three scientists at Bell Labs developed the first commercial photovoltaic (PV) cells, panels of which were capable of converting sunlight into enough energy to power electrical equipment. PV cells powered satellites and space capsules in the 1960s, and continue to be used for space projects.
In the 1970s, advances in solar cell design brought prices down and led to their use in domestic and industrial applications. PV cells began to power lighthouses, railroad crossings and off shore gas and oil rigs. In 1977, solar energy received another boost when the U.S. Department of Energy created the Solar Energy Research Institute. It was subsequently renamed as the National Renewable Energy Laboratory (NREL), and its scope expanded to include research on other renewable energy sources. NREL continues to research and develop solar energy technology.
In the last 20 years, solar energy has made further in roads and now is used extensively in off -grid and remote power applications such as data monitoring and communications, well pumping and rural power supply, and in small-scale applications such as calculators and wristwatches. But [Only registered and activated users can see links. ] has not yet achieved its potential to become a major contributor to world electrical grids.
Private and government research and development in solar energy technologies have led to continuing innovation over the last 30 years. The conversion efficiency of PV cells — that is, the percentage of sunlight hitting the surface of the cell that is converted to electricity — continues to improve.
Commercially available cells now on the market have efficiencies approaching 20 percent.
Cell efficiencies achieved in research laboratories recent surpassed 40 percent. The worldwide PV market has grown by an average of 30 percent annually for the past 15 years, an increase that has improved economies of scale for manufacturers.
As a result, the cost of electricity generated from PV modules has fallen significantly, from more than 45 cents per kilowatt hour (kWh) in 1990 to about 23 cents per kWh in 2006.
In 2006 and 2007, a shortage of silicon (a primary component of crystalline silicon PV systems) temporarily increased PV module costs, but prices are expected to decline once again between 2008 and 2011, when silicon plants currently under construction are completed.
After obtaining approval of his accelerator, other admixtures, cement, and aggregate from the Engineer, the contractor shall* submit his proposed shotcrete mix designs to the Engineer for initial evaluation and comment. Such designs shall include both regular shotcrete as well as a mix design for use as a finishing layer in areas receiving a waterproofing membrane. No sooner than 14 days after mix design submittal, the Contractor shall (afer giving the Engineer at least 48 hours prior notice) prepare test panels his proposed. Shotcrete mix design in the presence of the Engineer.
Selection Criteria for shotcrete mix designs
Mixture proportions (mix designs) for shotcrete shall be selected and approved on the basis of compressive strength tests of cores obtained from test panels fabricated in accordance with ASTM C1140 and the initial and final set properties of the mix as determined in accordance with ASTM* C403.
Test panels shall be at least 762mm by 762mm. Test panels shall be made* using equipment, water pressure, air pressure and nozzleman the Contractor proposes to use for the work. Four separated test panels shall be made, two shall be vertical placements (representing side placement of shotcrete) and two shall be overhead placements. From each panel, ten (10) cores shall be taken. Two (2) from each panel for testing at 8 hours after placement, two (2) from each panel for testing at 24 hours after placement, two (2) from each panel for testing at 3 days after placement, two (2) from each panel for testing at 7 days after placement and two (2) from each panel for testing at 3 days after placement. Cores shall be taken perpendicular to the test panel and cured in accordance with the requirements of ASTM C1140, until testing.
Mix design acceptance criteria
a. All cores shall meet or exceed the mix design strength requirements for 8 hours, 24 hours, 7 days and 28 days. The average compressive strength of all cores (for 8 hours, 24 hours, 7 days and 28 days) shall be 1.2 times the required minimum compressive strength specified.
b. Material from each sample panel shall meet or exceed the minimum initial and final set requirement.
Revision of approved mix design
Shotcrete mix designs, as approved by the Engineer, shall be based on the approvals for cement, admixtures and aggregates used with an approved mix. If the Contractor, for any reason, change his cement, any admixture and/or his aggregate source or gradation, the Contractor shall submit and obtain approval for any/all new mix constituents and provide a new mix design for approval by the Engineer.
Basically, internal surface coating in potable water tank shall be smooth, easy-to-clean and has high mechanical resistance to accommodate the erosion of movement of water. Most important thing is that this coating shall not adversely influence the quality of water.
Sika has been supplying SikaTop Seal 107 or Icosit TW 450 to large numbers of water projects. This product has been tested in local and international laboratory and meets the requirement for waterproofing and protective coating in contact with potable water.
In waste water treatment, besides providing waterproofing properties, internal surface coating shall be able to protect the reinforced concrete structure from aggressive chemicals attack. The degree of chemical attacks then depends on type of chemical involved, time of exposure as well as service temperature itself.
To give the right solution, it is necessary to know all these information before hand. As reference, herewith is some Sika products that have been applied for waste water treatment internal coating: Inertol Poxitar F, 2-part protective coating on epoxy coal tar pitch base and Sikagard 63 N, high build, chemical resistant epoxy resin coating.
In providing waterproofing system to concrete water tank, a good surface coating does not by itself makes a water tank waterproofed. Area of weaknesses are often found at the openings, pipe entry and construction joint or expansion joint system and for these areas waterstops and joint sealant have become an integral part of the whole waterproofing system.
Various types of waterstops are available from Sika, ranging from Sika Waterbars- flexible PVC waterbar to Sika Hydrotite – water swellable profiles. Sikaflex PRO-2HP is one of joint sealant available from Sika. This polyurethane based joint sealant is also has test certificate in compliance with potable water. Sikaflex Pro-3WF is usually used to seal gap & opening of joints when chemical resistance is required especially in waste water treatment plants. Sikadur Combiflex a highly chemical resistant PVC is also available to seal large or wide gaps and openings.
Basically concrete mixture is composed of cement, aggregates, admixtures and water. This article will discuss on cement in concrete.
Portland cement is the most common type of cement in general use. It is basic ingredient of concrete, mortar and plaster. English engineer Joseph Aspdin patented Portland cement in 1824.
It is made by heating limestone (calcium) with clay until all water molecules are gone (calcination) and finely grinding it. This product (called clinker) is mixed with a source of sulfate (most commonly gypsum) which regulates setting. The strength of cement is related to its fineness or specific surface. Cement is a mixture of oxides of calcium, silicon and aluminium.
When portland cement and similar materials are mixed with water, the resulting powder will become a hydrated solid over time.
The water molecules react with the cement, creating crystalline structures, which grow out from the cement molecules and bond the other components* together, eventually creating a stone-like material.
The basic of the chemistry of cement are mostly understood, but the variations in the raw materials make 100% control of industrial process nearly impossible.
For these reasons, frequent controls are required for the production of concrete and admixture have to be adjusted to the* varying raw materials used in the concrete, depending on the source.
The most common types of portland cement are:
Type I: Portland Cement – General use
Type II: Composite Cement (>65% portland) – Moderate resistance to sulphates
Type III: Blast furnace cement – High early strength
Type IV: Pozzolan cement -Low hydration heat
Type V: Composite cement- High resistance to sulfates.
Again, concrete is a construction material that consists of cement (commonly portland cement), aggregate (generally gravel and sand), water and admixture. Concrete solidifies and hardens after mixing and placement due to a chemical process known as hydration.
If the flooring gets failed, never blame the product first. The majority of flooring failures are due to application mistakes or carelessness.
Failures can have root causes:
Prior to flooring application
During flooring application
After application, prior to service
Failure factors prior to flooring application
Design failures: two weak substrate, poor reinforcement.
Wrong flooring product selection: unsuitable for actual working conditions.
Age of material: Shelf life exceeded
Improper storage conditions:* temperature/humidity/leaks…
Wrong mixing proportion: not all component added or even improper weight or packaging)
Bad or no substrate evaluation:
Streng: Compression, Cohesion or pull-out
Wrong mixing tools/equipment
Inadequate surface preparation
Substrate too old (primers which are not sticky)
No scabbing, grinding, shot or sand blasting when required
No priming/ inadequate priming/no dampening/saturation
No broadcasting, no blinding when required
Inadequate QS type
Superficial condensation (not checking ambient conditions and dew point)
Excessive surface humidity – H2O reacts with isocyanides resulting of CO2
Insufficient mixing time (leaving lumps in mortars, colour streak in resin resins, etc.
Only one of a two component system applied (no hardener in Epoxy system)
Not pouring epoxy into another container (may leave unmixed material in the bottom edges)
Supervision of application required: improperly trained applicators
two low temperature -> no reaction (cementitious or epoxy)
high ambient humidity -> bad film formation of water based resins
liquid applied membranes: delayed film formation causes blistering
single layer facade mortar: carbonation
No homogenisation of components prior to mixing. Setting of pigment or aggregate, causes not homogeneous results or performance.
Water or solvent addition to increase yield: make application easier but ruins product.
Wrong or inadequate application tools
Improper application thickness: too thin may not have enough material to achieve full properties or too thick may cause setting, cracking…
Contamination of surface in between layers/coats by foreign materials: dust, chemical incompatible products (silicones), welding particles, etc,
Pot life not controlled: end of pot life not visible
Contamination from release agents on the pin-rollers used.
Sabotage: addition of foreign substrate to the mix.
Weakening of the concrete substrate due to sulfate contamination in high water table.
Proper training or simply reading the Product Data Sheet and Method Statement with prevent most of above factors.
Failure factors after application and before service of flooring
Other trades present, working on the floor without properly protecting it.
Scratching by pulling loads over the surface
Failure factors during service of flooring
Inadequate service temperature
Unsuitable chemical environment
Unsuitable cleaning methods
Unexpected or modified working condition over the service time of application.
These can be traced back to bad product selection, or lack of information when specifying a product or system.
Selection and Design of the Industrial Flooring
What causes the deterioration must be taken into account:
Mechanical: Abrasion/ Erosion/ Impact/ Vibration
Physical: Temperature/Humidity/ Water/Frost
Chemical and Biological: Acids/ Oil/* Grease/ Gas/ Micro-organisms
and its intended used:
Design: Assessment/ Standards/ Calculation/ Measurement/ Details
Materials: Composition/ Properties/ Quality/ Durability/ Maintenance
Labour: Experience/ Care/ Quality Control/ Concern
Factors to take into account for the design and construction of industrial floorings
Ground conditions: strength, water table, type of soil, sub grade
Type of slab: ground supported or pile supported or suspended slab
Traffic and other loading requirements: frequency, duty and free or define traffic
Method of construction: in stages/bays, in strips or in large pour
Concrete mix design (especially critical w/c ratio):
The concrete deliveries must be of consistent quality. Otherwise negative impact on wetting/dry-shake workability/final finish performance (abrasion) and appearance.
A concrete slump in the range 75 to 110mm will normally give best results. This will depend on the placing method (manual/mechanical)
Do not use concrete where cement has partly been replaced with fly ash. This makes the mix is too sticky for proper dry-shake placing and workability, and will cause blisters during power-floating. Blisters are also caused by too early floatng or with inadequate tools (steel instead of wood or magnesium)
Slab thickness and reinforcement requirements: steel fibers or re-bars, other fiber types and combination
Jointless slabs or join spacing and positioning: Pinwheel contraction joint to separate columns. Design of joints according to traffic requirements. Less joints mean less cost (need for slab connectors) and less chance of damage and wear.
Surface smoothness and flatness: TR34, ACI 117, DIN 15185, ASTM E 1155
Durability and special operational conditions
Lighting: Use of lighter colour dryshakes helps reduce cost.
Again, never blame the product first. Failure can be due to the product, but are minimal and are mostly detected at QC:
Malfunctions in equipment: Adding too much or too little particular raw material
A proper design ensure the success of industrial flooring. Keep reading the* instruction on [Only registered and activated users can see links.
Sika accelerator range groups Sigunit D54 AF – powder accelerator intended for dry process and Sigunit L – liquid accelerator. Sika as innovative company has been the first one to introduce Alkali free accelerator like Sigunit 54AF, Sigunit 53MY range. Sikacrete products ranges based on Silicafume technology are sprayable shotcrete repair products.
During rock excavation it is sometimes necessary to stabilize rock massif. As injection aid, Intraplast Z* will allow producing high quality rock bolt grout.
When shotcrete as preliminary rock support, concrete lining will take place. Because water flowing through those concrete structures may contain sediment or flowing with high speed, it is necessary to produce high quality concrete.
Products range summary in excavation and shotcrete practice
Products Description Main use Sika 102 Waterplug, fast setting, cementitious mortar Stop pressure leak through rock or concrete Sigunit D Set accelerating shotcrete admixture in powder Suitable for dry mix SigunitÒ L Set accelerating shotcrete liquid admixture Suitable for dry and wet shotcrete process Sigunit D 54 AF Set accelerating shotcrete admixture in powder, Alkali free Suitable for dry mix Sigunit L54 AF Set accelerating shotcrete liquid admixture, Alkali free Suitable for dry and wet shotcrete process. Intraplast Z-HV Injection aid with expansion agent. Additive for Cementitious grout. Sika Rock Anchor IBO Shrink compensated, thixotropic Cementious grout for IBO Anchor, in soft and unstable conditions. Suitable when IBO Anchor type is required, IBO means injection boring outside thread. IBO Anchor are self drilling anchors. Sika Rock Anchor SN Shrink compensated, thixotropic Cementious grout for SN Anchor. Grouted into the drilling hole with a grouting pump before the anchor placement.
In the various and complex building structures composing a hydro power plant project, it is not unusual that concrete (or steel) must be coated.
Concrete must be coated in order to be waterproof or to provide high abrasive surface resistance. In certain case coating must be decorative coating.
For instance, Inertol Poxitar F – 2 components epoxy/coal tar base, will be used to protect either steel or concrete against abrasion flow (e.g. penstock lining).
Concrete or steel that need a protective coating suitable for contact with drinking water should be coated with SikaTop? Seal 107 – 2 components flexible waterproofing slurry will be used as an internal or external waterproofing coating.
Powerhouse facilities as building will require a decorative and efficient flooring system.
Owing to its Sikafloor range, Sika is offering suitable flooring system for the following requirement for instance :
• Abrasion resistance (low – medium – high)
• Chemical resistance (low – medium – high)
• Impact resistance
• Antistatic flooring
Products range for protective coating and flooring coating:
Products Description Main use Inertol Poxitar F Heavy-duty coal tar epoxy coating for steel and concrete. Suitable for damp substrate. Good abrasion resistance. SikaTop Seal 107 Flexible protective and waterproofing slurry For external and internal waterproofing.* Suitable in contact with potable water.
There are significant developments in concrete technology for a number of different and unique applications. Shrinkage compensating concrete is a concrete made with an expansive cement which, when properly restrained by reinforcement or other means, will expand by an amount equal to or slightly greater than the anticipated drying shrinkage.
Ideally a residual compression will remain in the concrete reducing the risk of shrinkage cracking. In the USA and Russia, expansive cements are produced as an enity, whereas in Japan they are produced by adding expansive admixtures to ordinary porland cement (OPC). A number of types of expansive cements have been used in USA namely Types K, M and S but type K is most prevalent. These cements which either contain or are blended with combinations of calcium sulphate,* calcium aluminates and calcium aluminate sulphates. In Japan another type of expansive cement. not based on sulphate and owing it s expansive properties to hydration of free lime, is used.
Care must be taken to ensure that continuous wet curing is provided for at least 7 days after placing to ensure that the expansion develops. Care also needs to be taken to prevent plastic shrinkage cracking. Expansive cements have been used to produce both shrinkage compensating concrete and self-stressing concrete for use in slabs, pavements, prestressed beams and roofs.