Behaviour of Normal Concrete Us ing Superplasticizer under Different Curing Regimes
The performance of concrete primarily depends upon the type and ratio of its constituents, compaction, curing conditions and admixtures used during curing process. Part of this research emphasis to calculate the consequences on strength of concrete when water-cement ratio is constant and the increase in slump occurs with the increase in amount of superplasticizer by percentage. The rest of the investigation is carried out to study the effects of superplasticizer with different dosages under different curing regimes at an ambient field temperature ranges between 45°C-50°C. For this purpose, a concrete mix at 20MPa with all parameters constant was prepared by using an ASTM C494 type A, and F, anionic melamine polycondensate non-toxic superplasticizer with no chlorides. Different dosages of superplasticizer were used in different batches of all 95 specimens, and cured under different curing conditions and then tested for compressive and tensile strengths following ASTM standards. In all cases, th e water curing up to 28 days testing showed maximum strength. The highest and lowest values of compressive strength were obtained with the addition of 0.5% and 1% superplasticizer respectively. It was found that without increasing the W/C ratio, the addition of superplasticizer exhibits increase in strength.
Construction Calculations Manual
Construction Calculations is a manual that provides end users with a comprehensive guide for many of the formulas, mathematical vectors and conversion factors that are commonly encountered during the design and construction stages of a construction project. It offers readers detailed calculations, applications and examples needed in site work, cost estimation, piping and pipefitting, and project management. The book also serves as a refresher course for some of the formulas and concepts of geometry and trigonometry. The book is divided into sections that present the common components of construction. The first section of the books starts with a refresher discussion of unit and systems measurement; its origin and evolution; the standards of length, mass and capacity; terminology and tables; and notes of metric, U.S, and British units of measurements. The following concepts are presented and discussed throughout the book: Conversion tables and formulas, including the Metric Conversion Law and conversion factors for builders and design professionals Calculations and formulas of geometry, trigonometry and physics in construction Rudiments of excavation, classification, use of material, measurement and payment Soil classification and morphology, including its physicochemical properties Formulas and calculations needed for soil tests and evaluations and for the design of retaining structures Calculations relating to concrete and masonry Calculations of the size/weight of structural steel and other metals Mechanical properties of wood and processing of wood products Calculations relating to sound and thermal transmission Interior finishes, plumbing and HVAC calculations Electrical formulas and calculations Construction managers and engineers, architects, contractors, and beginners in engineering, architecture, and construction will find this practical guide useful for managing all aspects of construction. * Work in and convert between building dimensions, including metric* Built-in right-angle solutions* Areas, volumes, square-ups* Complete stair layouts* Roof, rafter and framing solutions* Circle: arcs, circumference, segments
Study on urea-modified phenol formaldehyde resin adhesive
A reasonable technology to synthesize Urea-Modified Phenol Formaldehyde resins is realized by reacting phenol,urea and formaldehyde.The resin's feasibility is explored.The experiment result of shows that storable stability of the modified resin is good.The curing temperature of PUF resins was 25 ℃,lower than that of PF resins.The curing speed of PUF resins is faster than that of PF resins at the same curing temperature.The physical properties of the birch plywood bonded with PUF resins is similar to that of the birch plywood bonded with normal PF resins.The mechanical properties of the birch plywood bonded with PUF resins can achieve the demands of GB/T9846-1988.Free formaldehyde content of plywood is lower than the E1 level set by GB18580-2001.The cost of the adhesive is lowered for the use of urea,and its comprehensive properties is better than that of PF resins.