Air entrained concrete A major advance in concrete technology in recent years is the introduction of tiny disconnected air bubbles into concrete called air entrainment. Air entrained concrete results from using either an air-entraining cement or an air-entraining admixture during mixing. Adding entrained air to concrete provides important benefits in both plastic and hardened concrete,…
Needle Vibrator Needle type concrete vibrator These concrete vibrators are also referred to as poker or immersion vibrator. These are extensively used in building industry. A needle vibrator consists of a cylindrical casing made of steel and is vibrated by means of a flexible drive with an outer tube run from an operating machine which…
Asphalt shingles can be placed effectively over the existing roof. Nevertheless, it is recommended that if the existing roof layers exceed three, the old roofing structure is removed totally before fixing new shingles. Roof defects include thermal tearing, loss of granules, and curling. Basics of Asphalt Roofing Shingles Asphalt shingles are basically a roofing material…
Crushers are being used in the construction industry since the ancient history. Hydraulic crushers have been developed with a greater speed of crushing. Devices have been incorporated that prevent large size materials from entering the crusher. Basics of Crushers A construction crusher signifies a piece of equipment that is intended to reduce the size of…
Determine splitting tensile strength of cylindrical concrete specimens OBJECTIVE: This method covers the determination of the splitting tensile strength of cylindrical concrete specimens Theory: Age at Test – Tests shall be made at recognized ages of the test specimens, the most usual being 7 and 28 days. Where it may be necessary to obtain the early strengths,…
Factors affecting choice of concrete for a structure The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. 1. ECONOMY Frequently, the foremost consideration is the overall cost of the structure. This is, of course, a function of…
Suitability Of Water For Concrete Mixing OBJECTIVE To assess suitability of water for use in concrete mix. EQUIPMENT § Measuring cylinder § Cube moulds § Trowel § Tamping rod § Vibrating table § Testing machine PROCEDURE 1. Analyse water for its chemical compositions as per IS 3025-1964 and compare these with permissible limits given in IS: 456-2000. 2. In case water does not satisfy the permissible limits or…
This article will discuss different types of concrete cracks. After finishing the article, you will know how to repair concrete cracks. Some Common Reasons for Concrete Cracks 1. Uneven evaporation of moistures: The uneven evaporation of moisture from concrete causes various types of cracks. If the water evaporated from the surface of the freshly placed concrete faster…
The possibility of formwork reuse is determined by the type of formwork and the nature of construction. Reusing concrete formwork can reduce construction costs significantly if proper planning and handling is applied. Formworks are molds where concrete in its plastic form is poured so that it can be molded into the desired shape, size, position, and more importantly, its…
The health risks involved in asbestos has led to its being removed and replaced. There are persons and organizations specialized in asbestos abatement procedures. Even this asbestos abatement exposure does lead to health risks and requires companies to follow EPA guidelines. Asbestos Related Health Problems Led to Asbestos Abatement Asbestos is a group of minerals…