Effect of aging on the penetration resistance of sands

1995 ◽  
Vol 32 (5) ◽  
pp. 767-782 ◽  
Author(s):  
R.C. Joshi ◽  
Gopal Achari ◽  
Shenbaga R. Kaniraj ◽  
H. Wijeweera

The main objective of this study was to understand the effect of aging on the penetration resistance of freshly deposited sands. Two types of sand, locally available river sand used as masonry sand and Beaufort Sea sand, were selected for the study. The sands were allowed to age under a constant stress of 100 kPa in a specially designed apparatus in a dry state, as well as submerged in distilled water and in simulated sea water. Penetration resistance of the sand beds was measured periodically by pushing 4 probes into the sand bed. Mineralogical and fabric studies on freshly deposited and aged sand samples were conducted to detect the effect of aging, if any, on sand grains. The results indicate that aging significantly increases the penetration resistance of sands. The rate of increase in penetration resistance was higher for the submerged sand as compared with the dry sand. The increase in penetration resistance of the sand in a dry state was attributed to rearrangement of sand grains. In the submerged state, besides the rearrangement of sand particles, partial cementation caused by precipitation of salts and probably also silica on the sand grains and in the pores resulted in the larger increase in the penetration resistance. Key words : sand, aging, penetration resistance, freezing and thawing, sea water, distilled water.

1964 ◽  
Vol 41 (3) ◽  
pp. 499-511
Author(s):  
P. S. MEADOWS

1. A simple method is described for determining the substrate preferences of Corophium volutator (Pallas) and Corophium arenarium Crawford. 2. If offered a choice of its own substrate with that of the other species each prefers its own. 3. Level of illumination and colour of substrate have little effect on choice. An animal's size and hence its age has little effect on its substrate preferences. 4. C. volutator prefers a substrate previously maintained under anaerobic conditions, C. arenarium vice versa. 5. Treatments which kill, inactivate, or remove micro-organisms render sands unattractive to Corophium. These include boiling, acid-cleaning, drying, and soaking in fixatives or distilled water. Attempts to make these sands attractive again failed. 6. Distilled water, and solutions of the non-electrolytes sucrose and glycerol at the same osmotic pressure as sea water, induce many bacteria to desorb from sand particles; smaller numbers are desorbed in the presence of solutions of electrolytes at the same ionic strength as sea water (NaCl, Na2SO4, KC1, MgSO4, MgCl2, CaCl2). Of all these, only distilled water and solutions of MgCl2 and CaCl2 reduce the attractive properties of sands. Hence the loss of bacteria from the surface of sand grains, though related to the ionic strength and composition of the medium, is not necessarily associated with a substrate becoming unattractive.


2019 ◽  
Vol 8 (3) ◽  
pp. 2999-3002

Constructions across seashore increasing day by day (likely road pavements, bridges, hotels etc.,) But these are facing so many challenges by less availability chances of normal sand, water and huge amount of availability of saline sand, water. Sea water has 35ppt of an average salinity but in some places around shoreline salinity of ground water may vary from 0 to 35ppt due to humidity and temperature of ground surface. It will effect on durability of constructions at shore. In this investigation, the effect of saline content on M40 grade concrete(for road pavements)made by river sand and sea sand with partial and complete replacement of sea water specimen strength was studied. Total 216 specimens were casted using PPC cement in that 108 were casted using river sand and 108 were casted using sea sand with partial and complete replacement of sea water to test 7,14,28 days compressive & split-tensile strength of concrete specimens. Compressive strength test was conducted on cubes and Split-tensile strength was conducted on cylinders. PPC (fly ash based) cement is preferable for marine constructions due to its low heat of hydration and it has good resistance against saline attack. Sea water replaced as by 20%, 40%, 60%, 80% and 100% with normal water for different salinity ranges of water. Salinity was tested by Salinity Refractometer. River sand was collected from Vamsadhara River near srikakulam and sea water and sand was collected from kalingapatnam near srikakulam.


1927 ◽  
Vol 11 (1) ◽  
pp. 43-56 ◽  
Author(s):  
John H. Northrop

The rate of swelling of Arbacia eggs in dilute sea water, studied by Lillie and by Lucke and McCutcheon, may be expressed by the formulæ derived for the rate of increase in volume of a solution enclosed in a collodion sac. The rate of swelling of slices of carrot in distilled water, measured by Stiles and Jørgensen, may be expressed by the equation derived previously for the swelling of similarly shaped blocks of gelatin.


2014 ◽  
Vol 875-877 ◽  
pp. 619-623 ◽  
Author(s):  
Suppachai Sinthaworn ◽  
Wasan Teerajetgul ◽  
Attasit Sirivachiraporn

In this study, the workability, the compressive strength and the water penetration depth under pressure for concrete incorporate with quarry waste as fine aggregate were investigated. The mix proportions of concrete were set into two classes of water to cement ratio (w/c = 0.4, 0.6). The first class (C1), the mix proportion is 1.0:0.6:2.0:4.0 (Cement: Water: Fine: Coarse). And the second class (C2), the mix proportion is 1.0:0.4:1.5:3.0 and adding the superplasticizer 1% of cement weight. The natural river sand, which use in concrete, was partially replaced by quarry dust at the rates of 0% (no quarry dust), 50% and 100 % by weight of fine aggregate. The results show that concrete containing quarry wastes as fine aggregate decreased the workability and do not significantly affect the 28-day compressive strength whereas concrete incorporating with quarry dusts reduces the water penetration depth.


2020 ◽  
Vol 8 (5) ◽  
pp. 5625-5633

Worldwide, concrete is predominantly used as a versatile building material with its highest consumption on the earth. Nevertheless, its exigency accelerates day by day exhausting restricted natural resources in its manufacturing. Consequently, in order to prevent the degradation of these natural confined aggregates resources, it’s highly essential to employ other alternative profuse materials in their place. On the one hand, the sea Sand is existing in huge quantity below seas and oceans while on the other hand, restricted river Sand resources are being quarried haphazardly and hence reaching to their end. What’s more, to flashlights on, the production of every ton of cement contributes to the emission of an almost equal quantity of CO2 with high energy consumption. Also, it is worth mentioning that freshwater resources are in the limited quantity and, therefore, mankind is not getting sufficient fresh water even to drink in some corners of the world. In present experimental investigations, all the above burning dilemmas are kept in mind and hence, the sea Sand is used as an alternative to river Sand whereas sea water is used instead of distilled water for laboratory investigations on the properties of Geopolymer concrete and mortar in the total absence of Ordinary Portland Cement. The results demonstrated that the sea sand and seawater have no doubt affected the strength of Geopolymer concrete and mortar but just insignificantly.


Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.


1992 ◽  
Vol 25 (11) ◽  
pp. 117-124 ◽  
Author(s):  
N. Watanabe ◽  
S. Sakai ◽  
H. Takatsuki

Examination of individual degradation paths (biodegradation and photolysis) of butyltin compounds (especially tributyltin: TBT) in natural waters was performed. Biodegradation of TBT and dibutyltin (DBT) in an unfiltered sea water in summer is rather fast; their half life is about a week. But pretreatment with glass fiber filter makes the half life of TBT much longer (about 80 days). Photolysis of TBT in sea water by sun light is rapid (half life is about 0.5 days), and faster than in distilled water or in fresh water. Degradation rates of each process for TBT are calculated in various conditions of sea water, and contribution rates are compared. Biodegradation will be the main degradation process in an “SS-rich” area such as a marina, but photolysis will exceed that in a “clean” area. Over all half lives of TBT in sea water vary from 6 days to 127 days considering seasons and presence of SS.


2017 ◽  
Vol 130 (1) ◽  
pp. 479-484 ◽  
Author(s):  
M. M. Mato ◽  
L. M. Casás ◽  
J. L. Legido ◽  
C. Gómez ◽  
L. Mourelle ◽  
...  

1963 ◽  
Vol 40 (1) ◽  
pp. 187-193
Author(s):  
M. J. WELLS

1. A method of teaching Octopus chemotactile discriminations is described. 2. The animals can be shown to be capable of distinguishing by touch between porous objects soaked in plain sea water and sea water with hydrochloric acid, sucrose or quinine sulphate added. 3. They can detect these substances in concentrations at least 100 times as dilute as the human tongue is capable of detecting them in distilled water. 4. They can be trained to distinguish between equimolar (0.2 mM) solutions of hydrochloric acid, sucrose and quinine. 5. They can also be trained to distinguish between sea water and fresh water or half-strength sea water or sea water with twice the usual quantity of salt. 6. The function of the ‘olfactory organ’ is discussed. 7. Chemotactile learning is discussed in relation to the means by which Octopus finds its way about the territory around its ‘home’


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