Aggregate Concentration in Israel, 1995–2015

2021 ◽  
pp. 272-306
Author(s):  
Konstantin Kosenko
1979 ◽  
Vol 31 (109) ◽  
pp. 225-234 ◽  
Author(s):  
A. F. Stock ◽  
D. J. Hannantt ◽  
R. I. T. Williams

2001 ◽  
Vol 7 (6) ◽  
pp. 446-452
Author(s):  
Gintautas Skripkiūnas ◽  
Vitoldas Vaitkevičius

The results of experiments dealing with coarse aggregate concentration influence on the concrete strength and the structure of hardened cement paste and mortar of concrete are presented in the paper. Experiments were performed on concrete with dense coarse aggregate (crushed granite) which strength is more than strength of mortar and lightweight porous aggregate (expanded clay aggregate) with strength less than that of mortar. Physical and mechanical properties of concrete with dense coarse aggregate are presented in Table 1 and the concretes with the porous coarse aggregate in Table 2. The decrease of entrained air content with the increase of coarse aggregate concentration ϕσt were determined both for concretes with dense and porous coarse aggregate. The entrained air has a significant effect on concrete strength—1% of entrained air decreases the strength of concrete about 5% [11]. The influence of the coarse aggregate concentration on the compressive strength of concrete with the constant air content is presented in Figs 3 and 4. With the increase of coarse aggregate concentration the concrete strength decreases when the entrained air content in concrete is constant. The main reasons of the concrete strength reduction are the stress concentration and structural defects near the coarse aggregate. Coarse aggregate affects the structure of mortar. Dense coarse aggregate has negligible water absorption and does not change water content in mortar of concrete, and capillary porosity of mortar remains constant when the concentration of dense coarse aggregate ϕ st increases (Fig 5). Porous coarse aggregate (expanded clay aggregate) has large water absorption (more than 16%), therefore water content in mortar of concrete is reduced and capillary porosity of mortar is significantly reduced when the concentration of porous coarse aggregate ϕ st increases (Fig 5). The entrained air content in mortar with both dense and porous coarse aggregate decreases inverse proportionally to coarse aggregate concentration ϕ st (Fig 6). The investigations have shown that suitable selection of properties and volumetric concentration of coarse aggregate can reduce stress concentration in concrete and increase the concrete strength.


1980 ◽  
Vol 32 (113) ◽  
pp. 246-250 ◽  
Author(s):  
A. F. Stock ◽  
D. J. Hannant ◽  
R. I. T. Williams ◽  
D. W. Hobbs ◽  
M. S. Akman ◽  
...  

1981 ◽  
Vol 30 (2) ◽  
pp. 217 ◽  
Author(s):  
Robert M. Feinberg

2002 ◽  
Vol 16 (4) ◽  
pp. 137-160 ◽  
Author(s):  
Lawrence J White

I assemble two rarely used data sets to measure aggregate concentration in the U.S. in the 1980s and 1990s. Despite the merger waves of those decades, aggregate concentration declined in the 1980s and the early 1990s, but rose modestly in the late 1990s. The levels at the end of the decade were at or below the levels of the late 1980s or early 1990s. The average size of firm and the relative importance of larger size classes of firms increased, however. Gini coefficients for employment and payroll shares of companies showed moderate but steady increases from 1988 through 1999.


1981 ◽  
Vol 30 (2) ◽  
pp. 223 ◽  
Author(s):  
Lawrence J. White

Soil Research ◽  
1983 ◽  
Vol 21 (4) ◽  
pp. 411 ◽  
Author(s):  
G Blackburn ◽  
S Mcleod

Rain and dry deposition were sampled together for 28-day periods throughout 1974-75 at 27 stations, all but three being in the Murray-Darling Drainage Division (1.06 x 106 km2). Samples were analysed for calcium, magnesium, potassium, sodium, chloride and sulfate. Similar procedures continued during 1975-77 for six stations used previously and a new one. Rainfall records and the mean ionic concentrations, including estimates of HCO3 + NO3, indicate that the mean aggregate concentration for eight ions in 1974-75 ranges from 3 to 35 mgL-1 for 24 stations in the drainage division and from 14 to 23 mgL-1 for three stations near the South Australian coast. Higher concentrations in the drainage division refer principally to stations in a semi-arid district and are associated with relative abundance of calcium and HCO3 derived from the calcareous soils there. Terrestrial and oceanic sources of the ions are considered. Oceanic input of chloride is estimated using mean annual concentrations to give a maximum value and concentrations for the most rainy periods to give a minimum value. These estimates are compared with discharge of chloride by the Murray and Darling Rivers, with the conclusion that in 1974-75 the oceanic input of chloride to the Darling catchment was mostly retained there, but amounts equal to the accessions to the Murray catchment were probably all flushed out. Details are given in an appendix of NO3 concentrations determined by others at two stations in frequent samples of rain.


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