2. 0 DETERMINATION OF SPECIFIC GRAVITY 2.1 Introduction 2.1.1 OBJECTIVE To determine the specific gravity of a given soil by Density Bottle or Pycnometer Method 2.1.2 Learning Outcome Explain the Concept of Specific Gravity and its Uses Describe Lab Method for Determining Specific Gravity of Soils Perform the Specific Gravity Test on a given Soil Sample Determine Specific Gravity of the Soil Produce a report of the exercise 2.1.3 NEED AND SCOPE A knowledge of specific gravity is often used together with soil moisture content and unit weight in the calculation of soil properties like void ratio, porosity, degree of saturation, soil identification, soil classification, etc. It is particularly important when compaction and consolidation properties
The effect of addition of (PG) on the grindability. Setting times and the mechanical properties of OPC and OPC-limestone cement was also investigated. 2.Experimental 2.1.Materials Industrial clinker used for the production of ordinary type I Portland cement (OPC-I, 42.5N). Limestone with CaCO3 content higher than 75% was used in our study. The chemical oxide composition of OPC clinker and lime stone theoretical phase ratios calculated by Bogue formulae are presented in Table 1.
The mixture that has been released from the mold will be soaked in water and then tested to determine the compressive strength at the age of 3, 7, 28, 60, 120, and 180 days. the mix proportions of (cement : sand : granite) used are (1:1½:3, 1:2:4 and
It can be observed that the compressive strength decreases as the concrete temperature increases. The compressive strength for concrete temperatures between 35-40oC decreased by about 9% compared to the compressive strength for concrete temperatures between 20 to 25oC. From about 22˚ to 120˚C the concrete compressive strength decrease is attributable to thermal swelling of the physically-bound water that causes disjoint pressures. From 120˚C to about 300˚C there is a regain of compressive strength that is generally attributed to greater van der Waal’s forces as a result of the cement gel layers moving closer to each other during heating. At temperatures above 300˚C compressive strength losses can become significant probably due to differences.
Covering the concreted area to avoid excess evaporation or proper curing can help reduce this crack formation. The surface at which the concrete is supposed to be placed should be properly damped so that excess water is removed. Use of fibers or silica fumes can also help to reduce the crack formation. 5. Plastic Shrinkage in Shape of
silica fume concreteis used to produce high strength concrete.The factors that have a beneficial effect onstrength( like dense concrete, strongaggregates) also have a beneficial effecton abrasion resistance. silica fumeconcrete caters to all this needs. Chemical resistance A major reason for the improvedresistance of concrete to acidic andsulphate waters is the reduction in theca(oh)2 content of the cement paste,which decreases linearly with the amountof silica fume added. with 20% silica fumeby weight of cement ,very little of ca(oh)2produced by the Portland cementhydration is left in well hydrated cementpaste. Alkali aggregate reaction The amount of pozzolona needed for reducing the alkali aggregate expansiondepends on the reactivity of pozzolona.studies have shown that less than 10% of silica fume is found adequate for thispurpose as compared to fly ash whichrequires 30%-40% replacement High Strength Concrete High Performance Concrete (HPC)enhanced with silica fume is so strong itbecomes an economical alternative tosteel.
10, 30, 65 blows per layer) to obtain unit weights both above and below the desired unit weight. After allowing specimens to take on water by soaking for 4 days each specimen were subjected to penetration by a cylindrical rod. This load is divided by the load required to force the piston to the same depth in a standard sample of crushed stone (a high quality crushed stone material with a CBR value of 100%) AASHTO, 1993. Results of stress (load) versus penetration depth are plotted to determine the CBR for each specimen. The CBR at the 95% maximum dry density is determined from a graph of CBR versus dry unit weight according to the project technical
But researchers couldn’t lead to credible agreeable result in this aspect. Some of the reports showed high reduction in shrinkage by using polypropylene fibers, while others indicated small differences shrinkage between fibrous concrete and plain concrete. A pilot study reported in 1982 indicated that polypropylene fibers reduced shrinkage of plain concrete specimens by about 75 percent. However, more recent test results do not agree with these
The specific gravity is approximately 2.65 and dimensionally equal to or greater than 0.011 inch. Some treatment plants will require the removal of particles having the dimesnisions equal to or greater than 0.007 in. this procedure is economically favourable than other other stages of the treatment.
The activity incorporated results from previous two experiments, namely, Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis; and Liquid Limit, Plastic Limit, and Plasticity Index of Soils. The first one provided the sieve number, mass retained (g), Cumulative Mass Retained (g), Percent Retained, Cumulative Percent Retained, Sieve Size (mm), and Percent Passing, PPN. These were used to get effective size (D10 or 10% finer); 30% and 60% finer; uniformity coefficient (Cu); coefficient of gradation (CC); sorting coefficient (S0); gravel, sand, silt and clay size particles; and percentage distribution. Plasticity Index (PI) and Liquid Limit (LL) were derived from the second one. For the AASHTO classification system, the percentage passing of sieves Nos.