The Importance of Quality Control in Project Management and Evaluation of Construction Materials

Cem Ercan / Civil Engineer - Project and Technical Sales Manager - Emülzer Asfaltevi Tecrit Maddeleri San. ve Tic. Ltd. Şti.

In the Civil Engineering Department, Building Materials courses provide general information about products such as steel, cement, concrete, plaster and so forth. The theoretical knowledge provided in courses enables us to have sufficient understanding about material behavior and material science. However, the building chemicals sector is developing rapidly worldwide. As chemical engineers conduct more research on building materials, many new products have been introduced to the construction sector. Building materials manufacturers increase production diversity and develop products according to demand. These produced products need a "Quality Control" department in Building Project Management that inspects them both in terms of documentation and quality, and/or performs price-quality analysis. Quality control is not a direct field of study but is chosen as a specialization following graduation. This is generally ensured on large projects. Unfortunately, many contractors who have built thousands of housing units do not have this departmental organization. Rough and finish construction supervisors, on smaller-scale construction sites, as well as craftsmen and foremen, perform quality control duties, applying products from companies they had previously worked with. Quality is the production of goods that can meet customer expectations. Therefore, quality control must structure its test equipment and personnel according to the tasks it will perform. The needs vary greatly depending on the work to be done at construction sites. Within all these workflows, the quality department must operate as directed by management. There is no "quality" against management. During construction, according to technical specifications, the main building materials examined by the Quality Control Department are:

Concrete

On projects with approximately 50,000 m3 or more of concrete, in places where concrete transportation is not possible, many firms establish their own concrete plants for airport, dam, tunnel, highway, housing, and infrastructure projects. After the feasibility of the location for the concrete plant is determined and calculations are made regarding whether amortization costs will be covered, a decision is made on how to supply the concrete. If concrete will not be purchased externally or if special concrete design will be done, a concrete plant must be established. On-site prefabrication facilities are considered more suitable, especially on projects with many engineering structures. The compliance with standards of cement, water, sand, aggregate, mineral and chemical additives entering concrete is monitored. Tests are conducted to determine the properties of fresh and hardened concrete. If concrete is purchased externally, the quality department's workload is somewhat reduced. Concrete is a semi-finished building material that requires attention at every stage. The performance of concrete depends on the conditions from its production until placement and the maintenance conditions thereafter. Pre-tests should be conducted in laboratories for sprayed, prefabricated and ready-mix concrete additive tests. In recent years, "crystallized-property concrete additives," which are widely used, should also undergo pressure and water impermeability tests. Small prototype samples (mockups) should be prepared for this purpose. There are many types of concrete. Depending on the building type and function, concrete additives should be used after pre-testing. Pre-tests should ensure that all components are identical, with only the chemical additive being different. If we list some types of concrete: 1. Lightweight concrete, 2. Heavy concrete, 3. High-strength concrete, project concrete, mass concrete, 4. Dry mix, wet mix, 5. Roller-compacted concrete (RCC), 6. Underwater concrete, 7. Precast concrete, 8. Dry sprayed concrete, wet sprayed concrete, fiber concrete, 9. Reactive powder concrete, 10. Vacuum concrete, 11. Asphalt concrete, 12. Self-consolidating concrete (SCC), 13. Polymer concretes, epoxy concretes, 14. Vacuum concrete, 15. Architectural concrete, colored concrete, washed aggregate concrete (wash concrete), 16. Porous concrete, 17. Transparent concrete, etc.

Steel

Tensile tests are conducted on steel reinforcement samples taken from the construction site. After evaluating the test results and verifying the tensile, yield and breaking values, the reinforcement should be used. Although steel is also a semi-finished material, its inspection is somewhat easier compared to concrete. Supplied steel should be tested before entering the formwork, samples should be sent for tensile testing, and results should be examined. Reinforcement installed by steel workers according to the static project should be monitored.

Evaluation of Building Chemicals:

In architectural projects, depending on details, the names of several firms and product names are specified, or equivalent products are indicated. Indeed, the selection of building chemicals to be used depending on building type and project is quite important. Fundamentally, you cannot use a waterproofing product you will use on a terrace or in a wet area. Along with products from many international firms worldwide, domestic companies' products are also used in our country. The product to be used should be selected based on its price/quality performance along with the correct system detail. If the system of materials to be used is not detailed, returns will be problematic and costly. The building chemicals sector has increasingly become a service sector. Contractor firms sometimes award waterproofing work on a materials and labor basis, sometimes through barter agreements. In both stages, the quality control and technical office should be consulted regarding which product will be used in the project and the determination of system details. Although quality control is a department with a place in site organization and is viewed as an expense, it is one of the departments that will generate profit for the investor. Quality control should examine the products it selects in all their aspects. If a purchase request is created in a way that poses no technical problems, the investor firm will benefit from this work. It should assist procurement. For this, equipment and human resources must also be provided to meet the evaluation criteria. Our country has become the contractor of the world. Our contractors construct many engineering structures abroad such as dams, highways, railways, and industrial facilities. The quality departments and technical offices of contractors working abroad must be extremely strong. They should know ACI, AASHTO, DIN, GOST standards and design their laboratories according to the differences between them. Correct information should be provided to the contractor, subcontractor, consultant and project management. Quality control preparation for the project should be ensured before the bid. This matter is too important to be left only to the bidding department and will affect costs. Tests of products with standards defined in TSE and CE are conducted. However, many tests required regarding building chemicals cannot be performed in universities or independent testing laboratories. In this case, manufacturer declarations are sufficient. The standard rate positions prepared by the Ministry of Environment and Urbanization unfortunately do not cover every product. Many products no longer used in the market are still written in the standard rates, while the costs of products used by the private sector and even public projects are not included in the standard rates. This situation creates disagreements between the employer, contractor, subcontractor, supplier, consultant and inspector. After the Quality Control Department technically determines products and manufacturers, it must also review their prices. For the production of aesthetically pleasing, economical and safe structures, the initial evaluation of price/quality performance should be done by the Quality Control Department. The quality department should request necessary documents and samples for the product. If necessary, a few trial applications should be conducted on-site under the manufacturer's supervision. After approval within the site sequence and the correct product is decided upon, a purchase request should be submitted to the procurement department. Preparing a small system detail trial sample on-site will prevent many misunderstandings. Particularly for work such as terraces, wet areas, and balconies where waterproofing and thermal insulation will be done together, a small on-site demonstration would be very beneficial.

S.W. Nunnally brought the procurement section immediately after engineering and design when planning the structure. Thus, before construction, the site should reach a state ready to receive work.

Once the product to be used and quantity are determined, the procurement time of materials should continue according to the construction schedule. The Quality Control Department conveys the product or products it technically, theoretically and practically considers safe for use, along with alternatives, to procurement. Procurement should return to its registered suppliers in its portfolio and conduct market research during this process. The quantity of product required and the timing for procurement should be communicated to procurement. If the product is from foreign sources or is continuous and tonnage-based, procurement times should be communicated to suppliers. Frequent decision changes at construction sites make "everything urgent." This situation occasionally puts supplier against procurement. Products urgently requested are sometimes found to not have been used at all. The submission of requested price quotations from procurement to suppliers, evaluation of received prices – all of these are time-consuming tasks. If adequate time is not allocated for quality and procurement evaluation, material losses can be substantial. A product thought to be purchased cheaply can become expensive.

Controlled Quality Ensures Quality

I would like to present an example that has occurred here; at a construction site where a special concrete additive was used, one competing supplier offered the additive at a lower price to the customer and won the contract. However, following this rushed purchase made without site and laboratory testing, as a result of the product not reacting well with that cement, the total requirement increased from 20 tons to 60 tons. Although the unit price was low, the total amount spent for that job increased to much higher values. If the products to be used and quantities are determined upfront and conveyed to procurement, suppliers and applicators alike can make their own preparations more comfortably during this process. Suppliers can more easily determine shipping costs, deducting product price, evaluating raw material stock, and order status. On construction sites, the Quality Control department is viewed as "a department that impedes work." On the contrary, quality control's most important task is to pave the way for production, supporting manufacturing and clearing the path. Quality control should also ensure training at the site and raise standards. Contractors, subcontractors or personnel who attend seminars and receive training will continue to work on these projects and will also positively increase the firm's workmanship quality. Training certificates received from companies are used in Professional Competency Institution, Occupational Health and Safety, OHS certifications. For example, if how a repair work that occurs in a reinforced concrete structure should be performed is first explained theoretically and then practically, it becomes lasting. On large-scale construction sites, before application, "Product Application Method" (Method Statement) and Product Application Control Tables (Check List) are prepared for this purpose. After how the work will be done is determined theoretically, the matter is transferred to specialized application teams at the site. In practice, steps such as consumption control and application ease should be observed. By evaluating the work done with a different perspective, its feasibility can be checked this way. The importance of Building Project Management is increasing. Entrepreneurs may not know every fine point of a job, nor is there a need. However, whether the resulting product has good or poor performance directly affects the investor. In site organization, each unit has separate importance. The successful work done by each unit affects overall quality. Operating in conjunction with management, the quality department will complete the project successfully and profitably.