JP2006328849A - Half-deflective freezing restraining pavement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct pavement having the high freezing restraining effect by the synergistic effect of three icing restraining effects of the icing restraining effect by salinity, the icing restraining effect by a recess-projection shape and a construction material difference, the icing restraining effect of cement mix itself and the peeling-off effect by bentonite particularly included in the cement mix. <P>SOLUTION: When constructing half-deflective pavement for permeating cement milk 2 into a void of opening grain size asphalt concrete 1 (hereinafter referred to as opening grain size Ascon), the cement milk is composed of the cement mix composed of ultra rapid hardening cement, fly ash, the bentonite and a high performance water reducing agent, water, chloride and a hardening retarding agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semi-flexible freeze-reducing pavement method having a freeze-reducing function in road pavement work and the like.

  This kind of semi-flexible pavement is a method of spreading asphalt pavement by spreading an open-graded ascon with a high porosity on the road surface, spreading cement milk on the open-graded ascon, This is a pavement method that tries to make use of the flexibility and rigidity and durability of concrete pavement.

On the other hand, a chemical freezing suppression pavement that uses cement milk containing chloride and has the effect of suppressing freezing by the eluted salt content has also been proposed.
JP 7-310303 A

  However, in the case of this conventional pavement, since the antifreezing effect depends only on the amount of salt elution, there is an inconvenience that it is necessary to improve the aging maintenance of the antifreezing function.

  The object of the present invention is to solve these disadvantages. Among the present inventions, the invention of the method according to claim 1 is a void of open-graded asphalt concrete (hereinafter referred to as “open-graded ascon”). When constructing a semi-flexible pavement that allows cement milk to penetrate the cement milk, the cement milk is composed of a cement mix consisting of super fast-hardening cement, fly ash, bentonite and a high-performance water reducing agent, water, chloride and a set retarder. There is a semi-flexible anti-freezing pavement method characterized by that.

  The invention of the method according to claim 2 is characterized in that the open particle size ascon has a porosity of 20% to 28%, and the method invention of claim 3 is characterized in that the cement The mixing ratio of the mix is 40 to 55% by weight of super fast setting cement, 5 to 15% by weight of fly ash, 1.5 to 3.0% by weight of bentonite and 0.1 to 0.2% by weight of high-performance water reducing agent. Mix, 30-35% by weight of water, 6-12% by weight of chloride, and 0.05-0.15% by weight of curing retarder.

  As described above, the present invention includes the effect of suppressing ice formation due to salt content, the effect of suppressing ice formation due to uneven shape and material difference, the effect of suppressing ice formation of the cement mix itself, particularly the cement mix. It is possible to construct a pavement with a high anti-freezing effect due to a synergistic effect of the three ice accretion suppressing effects of the peeling effect by bentonite or the like.

  In the invention described in claim 2, since the porosity of the open-grained ascon is 20% to 28%, the effect of suppressing ice adhesion due to the uneven shape can be satisfactorily exhibited. In the invention according to Item 3, the blending ratio of the cement mix is 40 to 55% by weight of super fast-hardening cement, 5 to 15% by weight of fly ash, 1.5 to 3.0% by weight of bentonite, and a high-performance water reducing agent. Since it is 0.1 to 0.2 wt% cement mix, 30 to 35 wt% water, 6 to 12 wt% chloride and 0.05 to 0.15 wt% retarder, The adhesion prevention effect, the ice adhesion inhibition effect due to the uneven shape and material difference, and the ice adhesion inhibition effect of the cement mix itself can be exhibited more satisfactorily.

  FIG. 1 is a conceptual diagram of an embodiment of the present invention, where 1 is an open-graded asphalt concrete (hereinafter referred to as “open-graded ascon”), and cement milk 2 penetrates into the voids of the open-graded ascon 1. We will make a semi-flexible pavement.

  Here, the open-graded asphalt is a pavement having a surface layer of an open-graded asphalt mixture, and the open-graded asphalt mixture is a heated asphalt mixture composed of coarse aggregate, fine aggregate, filler, and asphalt and has a composite particle size of 2.36 mm. This means that the passage is 15-30%. The road surface of this mixture is very rough and is mainly used as an anti-slip mixture. Asphalt is a bitumen (naturally produced as a distillation residue of petroleum). Soluble hydrocarbon mixture) Semi-solid or solid sticky substance as the main component. Of this petroleum asphalt, the one used for pavement is usually straight asphalt with a penetration of about 40 to 120. It is called oil asphalt.

  In this case, the porosity of the open particle size ascon 1 is 20% to 28%, and the cement milk 2 is composed of a cement mix composed of super fast hardened cement, fly ash, bentonite and a high-performance water reducing agent, and water. And a chloride and a curing retarder.

  Here, the ultrafast cement is a cement that exhibits a predetermined strength in about 3 hours when water is added, and has a larger amount of aluminum oxide than ordinary Portland cement, and contains magnesium oxide and sulfur trioxide. Newly added, fly ash is a kind of admixture, soot generated at power plants, etc., mixed with ordinary Portland cement to make fly ash cement, 5% of cement mass Those used above are called admixtures, and those using less than 1% of the cement mass are called admixtures.

  Bentonite is one of clay minerals and one of clay minerals mainly composed of a mineral called montmorillonite having a very high specific surface area.

  Chlorides are generally compounds containing chlorine, such as NaCl (salt), KCl (potassium chloride), etc. In addition to chlorides, those having a freeze-inhibiting function such as potassium acetate and formic acid. Sometimes used.

  A high-performance water reducing agent is an admixture intended to reduce the amount of water required in order to obtain a predetermined good workability by dispersing cement particles. In addition, the curing retarder is used to delay the curing according to the time required for the execution because the ultrafast cement has a very fast curing time.

  In this case, as shown in Table 1, the cement mix is 40 to 55% by weight of super fast hardened cement, 5 to 15% by weight of fly ash, 1.5 to 3.0% by weight of bentonite, and 0.1 to 0.00 of the high-performance water reducing agent. A cement mix composed of 2% by weight, 30 to 35% by weight of water, 6 to 12% by weight of chloride, and 0.05 to 0.15% by weight of a retarder is used.

The cement milk 2 has a compressive strength of 8 N / mm ² or more (cured for 3 days), a flow value (P float method) of 12 seconds or less (after completion of kneading), and a curing time of 2 to 5 hours. The amount of cement milk 2 used (L) is preferably the construction area (m ² ) × ascon thickness (m) × (void ratio ÷ 100) × 1000, and the ascon thickness is preferably 4-10 cm.

  In this embodiment, for example, the open-graded ascon 1 is laid and constructed on the base layer W made of asphalt concrete pavement, concrete pavement, etc. on the road construction surface. To remove the adhering material such as floating stones and soil, mask the parts not to be constructed with tape, etc., and plug both ends of the open-graded ascon 1 with sealing material such as mortar to prevent the cement milk 2 from flowing out. On the other hand, on site, using a grout mixer, cement milk consisting of super fast hardened cement, fly ash, bentonite and high-performance water reducing agent, water, chloride and hardening retarder 2 is mixed and stirred at a predetermined blending ratio, and the kneaded cement milk 2 is spread on the above open grained ascon 1 and spread. Spread the cement milk 2 on the surface of the Ascon 1 with rubber rake, etc., and let it infiltrate with a vibrating roller until it no longer bubbles in the staying state. Remove the milk 2 with rubber rake, etc., and after completion of the penetration, cure the cement milk 2 so that it does not enter the construction area until the cement milk 2 has hardened. After the curing period elapses, the masking tape is removed, the surroundings are cleaned, and traffic is opened after all work is completed.

  It should be noted here that before the cement milk 2 is infiltrated, curing is necessary until the surface temperature of the open-graded ascon is 50 ° C. or less, and moisture is removed by drying with a burner or the like at the time of masking. At the same time, stone powder and the like must be removed with a jar or blower. If the cement milk 2 is filled with moisture remaining in the open-graded ascon, floating water will be generated on the surface, the finish will be deteriorated, and the strength of the cement milk 2 will be reduced. In addition, during the penetration of cement milk 2, the properties of cement milk 2 are slightly different depending on the temperature and water temperature on the day of construction, so the flow value is measured using a P funnel, It is necessary to adjust the water temperature, and after about 15 minutes have passed since the mixing of the cement milk 2, the viscosity increases and the workability deteriorates. After kneading the completion of click 2 care should be taken to carry out the filling osmotic immediately on open-graded asphalt 1.

  As a binder, asphalt such as modified asphalt type II and high viscosity modified asphalt is used. This modified asphalt is a material added to normal straight asphalt as a rubber or thermoplastic elastomer modifier, or blowing, etc. The main operations are modified asphalt type II, high-viscosity modified asphalt for drainage pavement, semi-blown asphalt, etc. In this case, shown in the following Table 2 and Table 3, It was decided to lay an open particle size ascon 1 having an open particle size aggregate having a particle size distribution and a porosity of 25% having a Marshall standard value.

  And in this cement milk 2, the sample 1 shown in Table 4 and the sample 2 shown in Table 5 are produced, and the comparative sample of a conventional construction method shown in Table 6 is produced, and on the open grain size ascon 1 Sample 1, sample 2 and comparative sample cement milk 2 were infiltrated and subjected to an ice adhesion tensile test.

  In this ice adhesion tensile test, the one proposed by the anti-freezing pavement technology study group is used, that is, an iron plate having a diameter of 10 cm and a thickness of 2.0 cm with a needle punch nonwoven fabric pasted on the bottom is used as the thickness of the nonwoven fabric. Mounted on a specimen (approx. 250 cc) with a water depth of 2-3 mm so as not to exceed the thickness, fixed in ice at a predetermined temperature for 24 hours in a cold room, When installing, allow the needle punch to sufficiently absorb water, remove air pools, and then pull the iron plate fixed with ice with a special tensile tester from the pavement specimen, and the tensile force at that time will be referred to as the ice adhesion tensile force. To do. This ice deposition temperature is set to −3 ° C., −5 ° C., and −8 ° C., and the salt concentration is measured after the test is completed.

  As a result, the test results shown in Table 7 below were obtained.

  When this test result is analyzed, sample 1 and sample 2 clearly have smaller ice adhesion tensile force than the comparative sample of the conventional method, and therefore, the freezing suppression effect is large, and the influence of the ice adhesion tensile force due to the freezing temperature is It is recognized that it is very small, one is the effect of inhibiting icing due to salt, that is, the effect of peeling due to a decrease in the freezing temperature due to salt, and the second is the effect of inhibiting icing due to uneven shape and material difference, that is, The large unevenness of the road surface and the peeling effect due to the difference in the material between the asphalt aggregate and the cement milk (thermal expansion coefficient, surface shape), and third, the ice adhesion suppression effect of the cement mix itself, that is, bentonite contained in the cement mix It is presumed that a clear freezing-inhibiting effect was recognized by the synergistic effect of the three ice accretion-inhibiting effects of the peeling effect due to the above.

  In this case, since the porosity of the open-grained ascon is 20% to 28%, the effect of suppressing ice adhesion due to the uneven shape can be satisfactorily exhibited. In this case, the blending ratio of the cement mix Is a cement mix comprising 40 to 55% by weight of ultrafast hard cement, 5 to 15% by weight of fly ash, 1.5 to 3.0% by weight of bentonite and 0.1 to 0.2% by weight of a high-performance water reducing agent, and water. 30 to 35% by weight, chloride 6 to 12% by weight, and curing retarder 0.05 to 0.15% by weight. The effect of suppressing the ice adhesion of the mix itself can be exhibited even better.

  The present invention is not limited to the above embodiment, but the material of open-graded asphalt concrete, porosity, super fast hardened cement, fly ash, bentonite and materials and blending ratios of high-performance water reducing agent, chloride and hardening The material and the like of the retarder are appropriately changed and designed and constructed.

  As described above, the intended purpose can be sufficiently achieved.

1 is an overall conceptual diagram of an embodiment of the present invention.

Explanation of symbols

1 Open-graded ascon 2 Cement milk

Claims (3)

  When constructing a semi-flexible pavement that allows cement milk to penetrate into the voids of open-graded asphalt concrete (hereinafter referred to as “open-graded ascon”), the cement milk is composed of super fast-hardening cement, fly ash, bentonite and high-performance water reducing agent. A semi-flexible anti-freezing pavement method comprising: a cement mix comprising water, chloride, and a set retarder.   2. The semi-flexible freeze-suppressing pavement method according to claim 1, wherein the porosity of the open-graded ascon is 20% to 28%. The blending ratio of the cement mix is from 40 to 55% by weight of super-hard setting cement, 5 to 15% by weight of fly ash, 1.5 to 3.0% by weight of bentonite and 0.1 to 0.2% by weight of high-performance water reducing agent. The semi-flexibility according to claim 1 or 2, wherein the cement mix is 30 to 35% by weight of water, 6 to 12% by weight of chloride and 0.05 to 0.15% by weight of a retarder. Freezing control pavement method.

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