Compaction factor apparatus’ trowels, hand scoop (15.2 cm long), a rod of steel or other suitable material (1.6 cm diameter, 61 cm long rounded at one end ) and a balance.
Full Story »Eco-Friendly Building Materials
Today many people that are building or remodeling their houses choose to use eco-friendly building materials. An eco-friendly building material is one that increases the efficiency of energy used and reduces impact on human well-being and the environment. There are many different materials that can be used that are eco-friendly; from foundation, to [...]
ADVANCED COMPOSITE MATERIALS (ACMs)
ACMs can be defined as combination of materials appropriately arranged using reinforcing fibers, carefully chosen matrixes, and some times auxiliary materials like adhesive core and other inserts. These combinations after proper manipulation and processing result in finished structure/item with synergistic properties i.e. properties achieved after fabrication cannot be obtained by individual components acting alone. The [...]
CFRP LAMINATES FOR SHEAR STRENGTHENING OF CONCRETE BEAMS
The use of Near Surface mounted Reinforcement for concrete structures are not a new invention. A type of NSMR has been used since the 1940s, where steel reinforcement is placed in slots in the concrete cover or in addition concrete cover that is cast onto the structure. Here steel bars are placed in slots in [...]
CARBON FIBRE REINFORCED POLYMERS
The main impetus for development of carbon fibres has come from the aerospace industry with its need for a material with combination of high strength, high stiffness and low weight. Recently, civil engineers and construction industry have begun to realize that this material (CFRP) have potential to provide remedies for many problems associated with the [...]
FIBRE REINFORCED POLYMER
An FRP composite is defined as a polymer that is reinforced with a fibre. The primary function of fibre reinforcement is to carry load along the length of the fiber and to provide strength and stiffness in one direction. FRP represents a class of materials that falls into a category referred to as composite materials. Composite materials consist of two or more materials that retain their respective chemical and physical characteristics when combined together. FRP composites are different from traditional construction materials like steel or aluminium.
STRENGTHENING STRUCTURES
When strengthening is going to be undertaken all failure modes must be evaluated. Strengthening a structure for flexure may lead to shear failure instead of giving the desired increased load bearing capacity. It should also be noted that not only the failure mode of the strengthened member is important. If a critical member in a structure is strengthened, another member can become the critical one. Because of changed stiffness in an undetermined structural system the whole structure must be investigated. The strengthening should also designed with consideration to minimize the maintenance and repair needs. When a strengthening is designed the consequences from loss of strengthening effectiveness by fire, vandalism, collision etc. must in addition be considered.
COMPOSITES IN CONSTRUCTION
Composite is a mixture of two or more materials that differ in form, chemical composition and essentially insoluble.
There are two categories of constituent materials: matrix and reinforcement. The reinforcement imparts its special mechanical and physical properties to enhance the matrix properties. Composite produces properties unavailable from the individual constituent materials.
Due to the wide variety of [...]
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COMPACTION FACTOR TEST
COMPRESSIVE STRENGTH OF CONCRETE CUBES
To determine the compressive strength of concrete specimens prepared and to verify the strength requirements as desired in the mix design and stipulated in the IS code.
Full Story »SLUMP TEST
To study the workability (determine the consistency) of prepared concrete either in the laboratory or laboratory or during the progress of work in the field and to check the uniformity of concrete from batch to batch.
Full Story »COMPRESSIVE STRENGTH OF MORTAR CUBES
Take 200gm of cement and 600gm of standard sand in the proportion 1:3 by weight) in a pan. (The standard sand shall be of quartz, of light, gray or whitish variety and shall be free from silt. The sand grains shall be angular, the shape of grains approximating to the spherical form, elongated and flattened grains being present only in very small quantities.
Full Story »FINAL SETTING TIME OF CEMENT
Take 400 gm of cement in a pan. Prepare a neat cement paste by adding 0.85 times the water required to give a paste of standard consistency by the previous test. Start a stop watch at the instant when water is added to the cement. Keep the vicat mould on a non porous plate and fill the cement paste in it. After completely filling the mould, it should be shaken slightly to expel the air. Smooth off the surface of the paste making it level with the top of the mould.
Full Story »INITIAL SETTING TIME OF CEMENT (IS 4031, IS 269)
Take 400 gm of cement in a pan. Prepare a neat cement paste by adding 0.85 times the water required to give a paste of standard consistency by the previous test. Start a stop watch at the instant when water is added to the cement. Keep the vicat mould on a non porous plate and fill the cement paste in it. After completely filling the mould, it should be shaken slightly to expel the air. Smooth off the surface of the paste making it level with the top of the mould.
Full Story »STANDARD CONSISTENCY OF CEMENT
The standard consistency is that consistency, which will permit the vicat plunger to penetrate to a point 5 to 7mm from the bottom of the vicat mould when tested as described below.
Full Story »FLOWABLE FILL
Flowable fill refers to a cementitious slurry consisting of a mixture of fine aggregate or filler, water, and cementitious material(s), which is used as a fill or backfill in lieu of compacted earth. This mixture is capable of filling all voids in irregular excavations and hard to reach places (such as under undercuts of existing slabs), is self-leveling, and hardens in a matter of a few hours without the need for compaction in layers.Flowable fill is sometimes referred to as controlled density fill (CDF), controlled low strength material (CLSM), lean concrete slurry, and unshrinkable fill.
Full Story »BEAM CHARACTERISTICS
There are a number of properties of a beam that an Engineer should be aware of as they dictate beam behaviour when subject to a load and ultimately represent possible areas or mechanisms for failure. The main ones being:
Second moment of area (also referred to as the second moment of inertia): this depends on the cross section profile of the beam and is a measure of the resistance of the shape of the beam to bending.
Full Story »CIRCULAR PRESTRESSING
Circular Prestressing” is employed to denote the prestressing of circular structures such as pipes and tanks where the prestressing wires are wound in circles. In contrast to this term, “linear prestressing” is used to include all other types of prestressing, where the cables may be either straight or curved, but not wound in circles around a circular structure. In most prestressed circular structures, prestress is applied both circumferentially and longitudinally, the circumferential prestress being circular and the longitudinal prestress actually linear.
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