What’s Admixtures? Admixtures are anything other than portland cement, water, and aggregates that are added to a concrete mix to modify its properties. Included in this definition are chemical admixtures (ASTM C494 and C260), mineral admixtures such as fly ash (C618) and silica fume, corrosion inhibitors, colors, fibers, and miscellaneous (pumping aids, dampproofing, gas-forming, permeability-reducing agents).
Chemical and mineral admixtures Chemical admixtures used in concrete generally serve as water reducers, accelerators, set retarders, or a combination.
An air-water mixture is found from the heat and mass balance to be at 60°C (333 K) and 0.025 kg/kg (25 g/kg) absolute humidity. Calculate the other main parameters for the mixture. Take atmospheric pressure as 101,325 Pa.
Method: Consult item (vi) in Table 12-5 for the calculation methodology.
From the initial terminology section, specific humidity YW = 0.02439 kg/kg, mole ratio z = 0.0402 kmol/kmol, mole fraction y = 0.
Process Control In order to produce a product with consistently high quality, tight process control is necessary. A simple-to-understand example of process control would be the supply of water to a number of cleaning stations, where the water temperature needs to be kept constant in spite of the demand. A simple control block is shown in Fig. 1.1a, steam, and cold water are fed into a heat exchanger, where heat from the steam is used to bring the cold water to the required working temperature.
Cementitious materials include the many products that are mixed with either water or some other liquid or both to form a cementing paste that may be formed or molded while plastic but will set into a rigid shape. When sand is added to the paste, mortar is formed. A combination of coarse and fine aggregate (sand) added to the paste forms concrete.
Types of cementitious materials There are many varieties of cement and numerous ways of classification.
What is lightning or Thunder? Lightning, a high-voltage, high-current electrical discharge between clouds and the ground, may strike and destroy life and property anywhere thunderstorms have occurred in the past. Buildings and their occupants, however, can be protected against this hazard by the installation of a special electrical system. Because an incomplete or poor installation can cause worse damage or injuries than no protection at all, a lightning-protection system should be designed and installed by experts.
There are two distinct aspects of building fire protection: life safety and property protection. Although providing for one aspect generally results in some protection for the other, the two goals are not mutually inclusive. A program that provides for prompt notification and evacuation of occupants meets the objectives for life safety but provides no protection for the property. Conversely, it is possible that adequate building protection might not be sufficient for the protection of life.
for New Construction, Major Renovation, and Commercial Interiors Introduction Sustainable Design, Building, and Renovation Suggestions present a menu of options that can be adopted or implemented to integrate sustainable design, equipment, materials and other elements into new buildings and major renovations. The Suggestions include elements scored by the Leadership in Energy and Environmental Design (LEED) standard, as well as the best practices Bdmeter has implemented in our global network.
Suppliers worldwide are encouraged to adopt as many of the items in these Suggestions whenever feasible and applicable to your location and operations.
Many of the restrictions encountered in building design are imposed by legal regulations. While all must be met, those in building codes are the most significant because they affect almost every part of a building. Building codes are established under the police powers of a state to protect the health, welfare, and safety of communities. A code is administered by a building official of the municipality or state that adopts it by legislation.
For practical design, wind and earthquakes may be treated as horizontal, or lateral, loads. Although wind and seismic loads may have vertical components, these generally are small and readily resisted by columns and bearing walls. Vertical earthquake components can be important in the design of connections as in precast concrete structures. Wind often generates significant uplift forces that require special attention to vertical restraint and lateral support for members in reverse bending.