Dictionary of Construction Terms

Abak: Useful tables and charts developed and prepared for use in formulas for reinforced concrete calculations.

Abrams' Rule: A rule stating that, given the same concrete components and test conditions, the amount of cement and the water/cement ratio in the mixture determine the strength of the concrete, provided that the mixture is workable. Introduced in 1892 by Ferret in France and later by Abrams in the United States. According to this rule, the strength of a concrete or mortar depends solely on the ratio of the mass of water to the mass of cement used in the mixture.

Absorption: Water absorption (Fr. absorption)

ACI: American Concrete Institute.

Spans: The distance from the center of one support to the center of the other in slabs that rest freely or are fixed at both ends.

Acromar: A special name defined by a company that produces exterior paints based on acrylic copolymer emulsion, with a matte and grain-free finish.

Bond: Concrete and reinforcement deform due to the effects they experience. During this time, stresses transfer between the two materials. The occurrence of stress transfer without slippage between them is called bond. Bond is one of the most important beneficial properties of reinforced concrete. This allows the two materials to be used together and complement each other. Stress reduction and increase in the reinforcement occur through stress transfer to adjacent concrete regions. This can be explained by the direct formation of shear stresses in smooth steel bars. In ribbed bars, the transfer is assumed to be provided by shear stresses resulting from a complex stress state around the ribs. In both cases, the resulting shear stresses are also referred to as bond stresses.

Adiabatic: A situation where there is no heat input or output to the system.

Heavy Aggregate: An aggregate with an oven-dry particle density of at least 3000 kg/m3, as determined according to EN 1097-6.

Heavy Concrete: Concrete with an oven-dry unit weight (density) greater than 2600 kg/m3.

Aggregate Unit Weight: The unit weight of aggregate is determined by dividing the total weight of the aggregate particles filling a specific volume by the volume of the container. The aggregate unit weight can be measured in loose or compacted form. It is generally done for aggregate stock determination.

Aggregate Gradation: Gradation refers to the particle size distribution of aggregates, expressed as the percentage of the total weight of the aggregate falling within each size range. It is determined using a set of sieves. This definition is also known as "granulometry."

Aggregate Interlock: The mechanism by which aggregates on one side of a crack or joint provide load transfer by interlocking with aggregates on the opposite side.

Specific Gravity of Aggregate: The specific gravity of a substance is the ratio of its density to the density of water. Generally, it is calculated as "Specific Gravity, S = Weight of the substance in air / Weight of an equal volume of water." The weight of water equal to the volume of the substance is the weight of water displaced when the substance is immersed in water.

Flowable Fill Concrete: Flowable fill concrete is a fluid, low-strength material that can be excavated if needed after placement.

Alite: Tricalcium silicate (3CaO.SiO2). One of the most important minerals in clinker. It has a high hydration capability and contributes to the early strength of the clinker. The heat of hydration is approximately 502 kJ/kg. It constitutes 40-70% of Portland cement. It decomposes slowly below 1250°C during clinker cooling. If the clinker is rapidly cooled, it retains its form. The early strength of cement is directly proportional to the alite content.

Alkali-Aggregate Reaction: A chemical reaction in concrete that causes cracking.

Aluminate Modulus: The ratio of the percentage of aluminum oxide to the percentage of iron oxide in Portland cement. This ratio should be between 1.5 and 2.5 in normal Portland cements. In cements containing Al2O3, the aluminate modulus is higher. If the aluminate modulus is low, only C4AF can form in the clinker, and C3A cannot be found in the cement. This results in low heat of hydration and slow setting. High aluminate modulus and low silica modulus result in faster setting cements, requiring more gypsum addition to control the setting time.

Asbestos Cement: A coating material produced by mixing asbestos fibers with cement paste and molding under high pressure. Also known as Eternit.

Protrusion: The projections from the foundation wall of the footing. It is an extension to provide proper dimensions for the foundation.

Post-Tensioned Concrete: Concrete that is kept under compression after casting by means of the post-tensioning method to span large distances.

Abrasion Resistance: In aggregates, the Los Angeles test is most commonly used to determine abrasion resistance. It should be determined according to the Los Angeles coefficient specified in EN 1097-2. The Los Angeles coefficient is determined according to a specific application or final use. In concrete for structures, it is recommended that it does not exceed 50%. For road concrete or other surfaces subjected to abrasion, more durable aggregates may be required.

Acid Effect: Hydrated cement forms an alkaline environment. Acids react with alkalis to dissolve as calcium salts. The effect of acids depends on their ability to form calcium salts. For example, hydrochloric acid dissolves cement, releasing calcium chloride or insoluble calcium salts. Conversely, acids with low solubility are not aggressive. Sulfuric acid can appear as a biological product in sewers. Since the acid neutralizes in concrete, its effect is limited. Significant damage from acid effects requires a large amount of acid. However, the limited effect can release substances that cause other damages. For example, the high concentration of calcium chloride released due to the effect of hydrochloric acid can initiate the corrosion of reinforcing steel in undamaged concrete.

Hollow Block Slab: A waffle slab filled with blocks. A type of slab constructed with hollow clay or lightweight concrete blocks to prevent heat and sound transmission.

Moment of Inertia: In the study of physical phenomena, integrals defined over an area often appear. Second-order integrals are specifically called moments of inertia. It is the product of the area of each element within the cross-sectional area of a beam and the square of its distance from an axis. (Ix=Integral x² dA, Iy=Integral y² dA)

Accreditation: The process by which laboratories, inspection, and certification bodies providing conformity assessment services are certified to show that their qualifications and activities meet standards, ensuring products are safe and meet international standards. This certification is given special importance by the World Trade Organization and regional economic blocs to be accepted in international markets.

Principal Stress: The largest and smallest normal stresses on planes where the shear stress is zero are called principal stresses.

Open Tender Procedure: A procedure where all interested parties can submit bids.

Candidate: Natural and legal persons or joint ventures formed by them that apply for pre-qualification.

All Risk Insurance: A type of insurance covering various risks such as earthquakes, floods, landslides, storms, fires, theft, and sabotage for all kinds of vehicles, materials, equipment, machinery, transportation facilities, and completed parts of the work at the workplace from the start date to the final acceptance date.

Subcontractor: A natural or legal person who performs a part of the contracted work based on an agreement with the main contractor.

Key Technical Personnel: Experienced individuals required by the administration as a minimum qualification criterion to perform the tendered work.

Turnkey: A lump-sum contract based on the implementation projects and related item lists, where the total price offered by the contractor covers the entire work.

Abnormally Low Bid: Bids that are below the abnormally low threshold value determined by the administration.

Nitrous Oxide: Equipment in hospital facilities that reduces the high pressure from cylinders to the desired pressure for the hospital's nitrous oxide line.

Current: Electric flow.

Alternating Current: Electric current that changes direction at equal time intervals.

Ampere: The unit of electric current that measures the amount of electric charge passing a point per unit of time.

Antenna: Equipment that collects electromagnetic waves propagating in space and enables the transmission of these waves through transmission lines.