JPS5830397A - Backfilling material consisting essentially of washing sludge - Google Patents

Abstract

PURPOSE:To obtain backfilling materials which are hard to be run off by ground water or the like by mixing limestone washing sludge and/or dolomite washing sludge with lime such as quicklime, sand and Portland cement. CONSTITUTION:Limestone or dolomite is crushed coarsely, and the washing sludge slurry produced during washing thereof is controlled so as to contain 10- 25wt% water. Lime such as quicklime, slaked lime or dolomite is added at 5- 15wt% to said washing sludge, and after the water content thereof is controlled to 4-13wt%, 20-40wt% sand and 3-15wt% Portland cement is added and mixed, whereby a backfilling material is obtained. The resultant backfilling material has strength >=10 times higher than that of pit sand and river sand, is usable satisfactorily as a backfilling material ans prevents run-off by ground water, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cleaning sludge, which is characterized in that it is made by mixing limestone cleaning sludge and/or dolomite cleaning sludge with quicklime, slaked lime, limes such as dolomite, sand, and portland cement. This is the IJI return material.

Conventionally, limestone washing sludge or dolomite washing sludge is only partially used as fertilizer, raw material for cement, etc., and most of it is landfilled as waste confectionery. However, in recent years, with the increase in the production of limestone and dolomite, the amount of cleaning sludge generated has also increased, and the lack of land for landfill has become a problem, and effective utilization is desired.

In addition, in underground construction work for water supply, sewage, gas, and electric power, all excavated earth and sand other than high-quality earth and sand are discarded.
Newly backfilled with mountain sand, river sand, etc., but as the number of construction projects increases year by year, it is becoming difficult to supply mountain sand and river sand to meet the increasing demand for backfilling materials. In addition, in recent years, groundwater and other sources of mountain and river sand have formed in areas that have been backfilled with mountain and river sand, causing cavities or ground subsidence, and even causing damage to pipes, which has become a major social problem. There is.

The present invention was made in view of the above points, and it is possible to adjust the moisture content of limestone cleaning sludge and/or dolomite cleaning sludge, which are brittle vehicles, with lime. After V, sand and Portland cement are mixed to provide a backfilling material that is difficult to be washed away by groundwater or the like.

In the present invention, the cleaning sludge slurry generated when limestone or dolomite is roughly crushed and washed is
It is applied in an adjusted amount of 10 to 26% by weight. These physical properties include the following.

Particle size distribution (wt%) Chemical composition (wt%) Mechanical properties Particle size distribution was determined by a wet method. Chemical analysis is J1sR9
011 was followed. Mechanical properties are JISA1205.1
208.1211.

To these washed sludges, 5 to 15 percent lime was added, and after adjusting the water content to 4 to 13 percent by weight, 20 to 40 percent sand and 3 to 15 percent portland cement were added, mixed, and buried. Use as return material.

The backfilling material in the present invention has a design CBR of 170%.
In addition to the above, the arc L (which is more than 10 times that of conventional mountain sand and river sand) can sufficiently prevent outflow.91 The compaction characteristics of the returned material are as follows:
The expansion ratio is 0.2% or more and the design CLfR is 170% or more.

The total CAR is the value after 3) Trout 671M long, cured for 68 days, and immersed in water once every 4 days in a 15R11 diameter mold with a rammer of 45 to 9.

As described above, the uninvented backfill material is a backfill material in which limestone washing sludge and/or dolomite washing sludge is mixed with quicklime, slaked lime, limestone such as dolomite, sand, and portland cement, so its strength is high. It is more than 10 times more dense than sand or river sand, so it can be used as a backfill material, and it is very useful as a backfill material because it can prevent groundwater from flowing out, which is a disadvantage of mountain sand or river sand.

Next, examples of this invention will be shown.

Example 1 A backfill material using limestone washed sludge (moisture 16% by weight) and/or dolomite washed sludge (moisture 15:nj:ht%) mixed with hemi-lime, sand and portland cement in various proportions. ! 'Zhang Hi and & ii
' The results of the CBR test are shown in the table below. y, Ryokan No. 1 to 4 & J implementation biography, and shi are comparative examples.

Example 2 Expansion ratio and expansion ratio of backfill material using limestone cleaning sludge (moisture 16% by weight) and/or dolomite cleaning sludge (moisture 15% by weight) 6 - mixed with dolomite, sand and Portland cement at a mixing ratio of persimmons. Design C
The results of the BR test are shown in the table below.

From the table, it can be seen that when a backfilling material mainly composed of the limestone washed sludge and/or dolomite washed sludge of the present invention is used, a consolidation effect appears and the initial strength of the supporting force appears.

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Claims (1)

[Claims] A backfill material whose main material is washed sludge, which is made by mixing limestone washed sludge and/or dolomite washed sludge with quicklime, slaked lime, limestone such as dolomite, sand, and Portland cement.