How to use CrackMax HSCA（3）

IV． Hole depth: This varies with the shape of the material to be cracked or the break plan. Refer to APPENDIX as a guide line.

It should be noted that PROSTAR mixed with water can easily be applied by hand, when the hole depth is up to approximately 10 meters.When the depth is less than 3 times the diameter of the hole, less cracking will occur, the breaking effect is lessened and the time required for demolition is increased.

3 Use of thin steel pipe

In the case of a temporary concrete struture(to be demolished), place thin steel pipes(the thickness:﹤0.8mm.i.e. a sheath pipe for p.s.concrete) as holes before placing concrete instead of drilling.Whenever the struture need to be cracked, fill PROSTAR in the pipes. There is no change in breaking effect by the use of pipe.

Mixing

1 Equipment preparation

(1) container for one bag of PROSTAR—a metal round-shaped bucket or clean can with 10-20liters capacity

(2 )mixer for instance hand-mixer with saucer typed blade (hand mixing is available)

(3) water measure beaker or measuring cylinder

(4) Protective goggles

(5)Rubber gloves,

(6)Dust-proof mask

(7) Helmet

2 Mix proportion

PROSTAR 5 KGS (11 lb 1 bag)

Water 1.5liters (0.4us gallon)

Yield volume: approxmately3.1liters

Note: standard water ratio to PROSTAR is 30%

3.Mixing method

(1) Pour 1.5liters (0.4us gallon)of clean water into a container beforehand and add one bag (5kgs 11 ib)of PROSTAR gradually and mix well until it has good fluidity

(2) When the viscosity of the mixture of PROSTAR and water is too high to pour into holes add a little water to get good fluidity

However do not exceed 34@of water ratio (1.7 liters or o.45 us gallon per 5 kgs or 11.1b of PROSTAR)

(3) Mixing time using a hand-mixer is approximately 2-3 minutes it is recommended that a mechanical

mixer be used for large-volume jobs

When mixing by hand be sure to wear rubber gloves

4 Mixing water

(1) Use the clean water such as city water river Water Sea water which are not contaminated

with oil organic substances etc

(2) Use the proper temperature of water for each type of PROSTAR

(3) in particular cool water below 15℃(59f)must be used when average atmospheric temperature

is more than 30℃ (86f)for PROSTAR

(4)the cooler the water is the longer PROSTAR will remain fluid

5 Standard Quality

The quantity of PROSTAR to be used for cracking differs with the hole spaces and diameters. In table V, the relation between the quantity of PROSTAR used and the hole diameter is indicated for the hole of 1m depth, where PROSTAR was mixed at a water ratio of 30%

The average quantity of PROSTAR used per 1m3 is 5kg for the material to be broken when working at in virgin rock(8.4 lb/yd3).

For fragmentarion and reinforced concrete, an amount 2 to 4 times that is required.

Design the hole diameter and the spacing by also referring to Table IV or APPENDIX.

6. Filling

filling of the hole with PROSTAR

(1) PROSTAR should be poured into holes within 10 minutes after mixed with water

if PROSTAR is left as it is more than 10 minutes after mixed with water the is more than

10 minutes after mixed with water the PROSTAR gradually loses its fluidity so that it gets

difficult to pour the PROSTAR into holes

Note:

A.do not leave PROSTAR in a container beyond 10 minutes because blown-out shots may occur

B once its fluidity is gone it should not be diluted by re –mixing with water since the strength is greatly reduced

(2) PROSTAR must be poured into a hole to the brim.

(3)PROSTAR is best placed using a bucket with pour spout, coking gun or grouting pump, especially for a horizontal hole.Try to drill horizontal holes with some slope to help in filling.

7. Use of the polyethylene sack in hole

1) If there is water in the hoel, place a polyethlene thin sack equal to the hole diameter into the hole, insert a wooden rod into the bag and then fill PROSTAR into the sack. The PROSTAR in the sack will displace the water in the hole. There is no change in the breaking effect by the use of this kind of sack.

2)When there are many joints or large voids in the material to be cracked or when PROSTAR somewhat leaks from the hole, use the sack.

3)When much water of the slurry is absorbed to the material to be cracked (for instance, a dry concrete), use the sack or spary water into the hole.In cold temperature, avoid the water sprayed freezing in the hole.

4)When the materail to be cracked is in water, use the sack indicated in the above. Try to use the bucket or the pump when filling in the pipe, remove it up, and then tie the sack to avoid PROSTAR filled diluting. If there is no flow of water around an entrance of the hole, PROSTAR may directly be poured into the hole using the pump so on. It should gently dsiplace the water in the hole.

8.Curing

1） cover the filled holes with a plastic cover etc to avoid dilution of PROSTAR or any accident caused by blown-out shots

It is also not necessary to put on any restrictive cap。Just leave as it is and wait until cracks initiate

3） the time required for crack formation in material at 20℃ is approximately 10-20 hours the lower the temperature is ,the longer the time for crack for mat ion is

4） spraying the surface with water after cracks initiate tend to expand the width of cracks and speed up the cracking process

Note: be sure to wear protective glasses when confirming the occurrence of cracks

9. Secondary breaking

After cracks initiate secondary breaking is carried out with a hand –breaker a pick-hammer, a giant hydraulic breaker, a ripper, etc

A. It is best to wait until the PROSTAR has worked to full depth before removing rock or concrete since premature removal at the first sigh of a crack hampers the leverage effect of PROSTAR

Note: be a sure to wear protective glasses when secondary breaking is carried out

B the crack width for rock or concrete continues to increase with time and can become10-30mm (3/8-11/8) after several days depending on free surfaces available

TIME REQUIRED FOR CRACK FORMATION

The time required for crack formation in material at 20℃(68°F) is about 3-6hours. The lower the temperature the longer crack formation takes. The crack width for rock continues to increase with time and can become 10-30mm after sveral days, depending on free surfaces available. It is best to wait until the “PROSTAR” has worked to full depth before removing rock as premature removal at the first sign of a crack can hamper the leverage effect of “PROSTAR”