SRSBM Lab offers the All kind of Construction Material Test of Concrete, steel, Cement etc. by complying the requirement of relevant standards of testing.
Durability Test of Concrete:
Durability of concrete may be defined as the ability of concrete to resist weathering action, chemical attack, and abrasion while maintaining its desired engineering properties. Different concretes require different degrees of durability depending on the exposure environment and properties desired.
To have a sustainable concrete structure, durability is key. Use of inappropriate materials, poor construction practices, curing and mix designs, results in concrete structures often showing serious premature deterioration. This is a global problem that annually costs public and private sectors worldwide billions of dollars.
Tests such as water absorption, Compressive Strength of Cube/Core/Cylinder, surface absorption, water permeability, or chloride permeability are commonly specified.
These tests should consider the unique properties of the mix design when used to determine concrete's durability.
They also have some limitations and it is necessary to understand and recognize them.
A)Water Absorption: Absorption testing is a common method of determining water resistance. Tests such as BS 1881-122 measure the amount of water that penetrates into concrete samples when submersed. Low absorption is a positive result.
B)Compressive Strength of Cube/Core/Cylinder: Most of the concrete properties are related to the compressive strength that is obtained by compressive strength test by the method IS 516. Compressive strength test is the easiest, most economical or most accurately determinable test.
C)Water Permeability: This test is useful for basements, tunnels and water reservoirs, since it realistically recreates pressure conditions to which these structures are subjected. IS 516: Part-2/sec-01 & DIN 1048 Part 5 are equivalent tests measuring depth of water penetration into concrete samples subjected to 500KPa of hydrostatic pressure over three days. The smaller the depth of penetration, the greater the resistance to water under hydrostatic pressure.
D)Rapid Chloride Permeability test: This test is an Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration. The Test Method ASTM C 1202 monitor the amount of electrical charge passed through cylindrical specimens for six hours. The total charge passed, in coulombs, is related to the specimen's ability to resist chloride ion penetration. Lower levels of charge passed indicate higher resistance.
Rock testing
Rock testing measures is usually performed at high load on intact samples, sometimes at high temperature. There are a host of different tests you can run on rock from a variety of testing apparatus. Rock mechanics test is not only the basis for obtaining the mechanical parameters of rock but also an important means for studying rock mechanics and engineering. The RQD can provide an indication of rock quality in quarries for concrete aggregate, rock fill, or large riprap.
Cement testing
Cement is very important building material among other in construction industry. Cement has replaced all other building materials, like clay and lime, which ruled high for hundreds of years, in construction from last century. It has an ability to hold the structure together. Cement plays a major role within a concrete mixture and affects most important aspects of the mix, such as: workability, compressive strength, drying shrinkage, and durability. Through the process of hydration, cement particles react with water, binding the aggregate, and the strength matrix develops.
Testing of Cement
Various tests to which cements must conform are laid down to control the fineness, soundness, setting time, and strength of the cement.
A) Consistency: The strength of concrete depends on the quality of cement. In order to achieve good strength, the mortar should be consistent. he hydration of cement occurs in presence of water. Also, the consistency depends on the composition and fineness of the cement. Excess use of water makes cement brittle after hardening. The lower water-cement ratio affects the rate of hydration which in turn affects its strength. That is why determination of consistency is essential.
B) Fineness: Coarse Particles of cement reduce and affects the rate of heat of hydration, If the hydration rate decreases then it impacts the strength development of concrete or mortar. Fine Cement can easily blend with other ingredients. More fineness means high value of workability and thus increases the setting time.
C) Setting Time: The Setting Time of cement is time required for stiffening of the cement paste. Determining setting time helps to plan transportation of mixed concrete or mortar for pouring onsite.
D) Soundness: The soundness of cement refers to the stability of the volume change in the process of setting and hardening. If the volume change is unstable after setting and hardening, the concrete structures will crack, which can affect the quality of buildings or even cause serious accidents, known as poor dimensional stability.
E) Compressive Strength: Compressive strength is one of the most important properties of concrete and mortar. The strength of the binder (cement) therefore has a significant effect on the performance characteristics of the mixture and ensures the overall quality of the finished structure.
Pozzolanas
A pozzolana is a natural or artificial material containing silica in a reactive form. By themselves, pozzolanas have little or no cementitious value. Pozzolanas are materials with an amorphous siliceous or siliceous and aluminous content that react with calcium hydroxide in the presence of water to form cementitious hydration products (calcium silicate hydrates and calcium silicate aluminate hydrates).
The artificial pozzolans are Ground Granulated Blast Furnace Slag (GGBS), Pulverized Fuel Ash (PFA), Calcined Clay, Micro silica (MS), Rice Husk Ash.
Tests on Pozzolanas: Pozzolanas are used in concrete (sometimes in mortar) as a partial replacement of cement, therefore their properties must be found out. Various significance of tests which are pozzolanas must conform to control the fineness, soundness, setting time, and strength.
Significance of Testing: Pozzolanas increase the resistance of concrete against environmental attack, since they reduce permeability, absorption and ion diffusivity. Fly ash and silica fume reduce expansion, mass change and strength loss in ordinary Portland cement.
Aggregate:
In the construction industry, aggregate are used as filler material in the production of concrete and mortar. Aggregate occupy around 70% to 80% of the volume of the concrete, they give body of the concrete, reduce shrinkage and effect economy. The coarse aggregate form the main matrix of concrete and the fine aggregates form the filler matrix between the coarse aggregate.
Testing of Coarse Aggregate and Fine Aggregates.
Coarse Aggregates and fine aggregates are Generally used for making concrete to use buildings and infrastructure projects and Fine aggregates generally used in finishing work of building, thus aggregates are susceptible to wear and tear, compression loads, environmental attacks, etc. Therefore, its necessary to evaluate their quality and grade before using in those projects. Tests Like Particle size and shape, Specific gravity, water absorption, Mechanical testing, are some important tests for aggregates.
AAC Blocks
Autoclaved Aerated Concrete is a Lightweight, Load-bearing, High-insulating, Durable building product, which is produced in a wide range of sizes and strengths. AAC Blocks are lightweight compared to the red bricks. AAC blocks are three times lighter. They are mainly used as partition walls and Their light weight makes them less dead load on structure.
The durability of the AAC blocks depends upon the quality of manufacturing material. For proper walls construction the dimensions of blocks shall be uniform. For Proper strength and durability of blocks shall be tested for good quality.
Ceramic Tiles
Ceramic tile is made of clay that has been fired in a kiln. Ceramic tile is not as dense and has a higher absorption rate. ceramic tile is a very popular choice for floors, counter-tops and walls. The tile is coated with a special glaze that protects and seals it. This keeps the tile from absorbing stains while improving the durability of each piece. The glaze is also what gives ceramic tile its color and pattern. Several ceramic tile designs and sizes are available in the market.
Comprehensive testing and evaluation of ceramic tiles provides data to determine the suitability of the tile for proposed uses. For product conformity, quality control, safety, performance reasons, testing of ceramic Tile should be done.
Specific tests are, Dimensions and surface quality, Water absorption, Modulus of rupture/breaking strength, Mohr’s scratch Hardness etc.
HSD Bars
Reinforcement bars are the standard reinforcement for concrete reinforcement. Steels are used in concrete because, concrete is brittle in nature and steel is ductile.
Steel reinforcing bars or rebar is used in concrete construction to enhance tensile strength, complementing concrete's excellent compressive properties. Rebar also helps maintain structural integrity as concrete cracks from expansion and contraction cycles. The tensile strength of rebar steel and the tensile rebar-concrete bond strength are extremely important properties of rebar.
There are different tests for rebars that are conducted to determine the overall quality. The tests include the tensile strength test, bend test, rebend test, and percentage elongation.
Structural Steel
Structural steel is a category of steel construction material that is produced with a particular cross section or shape, and some specified values of strength and chemical composition. The word structural steel includes a broad variety of low carbon and manganese steels that are used in great numbers for civil and marine engineering applications.
Structural steel Tests Structural steels are tested for their Tensile strength, percentage elongation, conducted to determine the quality and strength.