Section 1 general sections are reserved in the standard specifications for correlation of special provisions and revised standard specifications with the standard specifications and for future expansion of the standard specifications the specifications are expressed in u. Item section aggregate 10101, 10102 ncdot 2012 standard specifications. Ufgs 32 11 33 cement stabilized base subbase course at. Cement treated base ctb is an intimate mixture of aggregate material andor granular soils combined with measured amounts of portland cement and water that hardens after compaction and curing to form a durable paving material. The strength of cement treated base should be kept within designated strength limits. Mix and place materials only when the moisture content of the soil to be used in the mixture meets the limits specified in this subsection. The base course shall be built in a series of parallel lanes using a plan of processing that reduces longitudinal and transverse joints to a minimum. The goal of microcracking is to prevent severe, wide cracks from forming and thus reduce the risk of problematic.
The contractor shall remove the remaining portion of concrete pavement slab by lifting and placing directly into haul trucks. A bituminous or portland cement concrete wearing course is placed on the ctb to complete the pavement structure. Improving the quality and strength of sub base and. Measurement by the cubic yard in final position and square yard is a plans quantity measurement. Cement treated bast ctb is a compacted mixture of graded aggregate, cement, and water, which is used as a base course for the construction of highways, airport runways and taxiways. Mixes containing 100%, 75% and 50% rap treated with portland cement of 0%, 2%. Total dust containing silica, respirable silicacontaining dust and respirable crystalline silica quartz levels should be monitored regularly to determine worker exposure levels. Cement treated base ctb has sufficient cement content to develop considerable cohesion and strength. There is one way to make road durable, it is by improving the pavement strength. Ctb can be mixed inplace with onsite soils or mixed in a central plant or pugmill depending on the project requirements. Adhere to ufc 002 unified facilities guide specifications ufgs format standard when editing. Road networks are most important infrastructure of our country. Cementtreated base ctb is a general term that applies to an intimate mixture of native soils andor manufactured aggregates with measured amounts of portland cement and water that hardens after compaction and curing to form a strong, durable, frost resistant paving material. Damage behavior of cementtreated base material sciencedirect.
The using of ctab,binder and surface course present the best economical choice. The strength of cement treated aggregate base represented by california bearing ratio cbr and compressive strength with percent higher than. This was based on the philosophy that a thicker section. Final draft update of item p304 cement treated base course 105 description 3041. Michigan department of transportation bureau of aeronautics standard specification p304 cement treated base course description 1.
Ufgs 32 11 34 portland cementstabilized base or subbase. This paper will look at the types and causes of reflective cracking in cement stabilized pavement bases and what techniques are available to minimize them for. This guide specification covers the requirements for portland cement stabilized base or subbase for airfields, roads and streets. Section 301soilcement construction page 3 mix and place cementtreated base or subbase only when the weather permits the course to be finished without interruption in the time specified. Cementtreated base ctb is a strong, frostresistant base for a concrete or asphalt pavement wearing surface. Section 301soil cement construction page 3 mix and place cement treated base or subbase only when the weather permits the course to be finished without interruption in the time specified. The construction manual contains policies and procedures related to the duties of caltrans division of construction personnel, is for information only, and is intended as a resource for personnel engaged in contract administration. Cementtreated base ctb is an intimate mixture of aggregate material andor granular soils combined with measured amounts of portland cement and water that hardens after compaction and curing to form a durable paving material. Service performance of cementtreated bases as used in. Contact with powerful oxidizing agents may cause fire andor explosions see section 10 of sds. Materials furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. More durable than aggregate surface, and can withstand heavy truck and equipment traffic with less dust. The mixed material shall be spread, shaped, and compacted in accordance with these specifications and. The aggregate shall be select granular materials, comprised of crushed or uncrushed gravel andor stone, or recycled cement concrete.
Cement treated base ctb is a nonconventional method used in road bases materials to improve its engineering properties due to the hardening of cement when moisture is present and extends the. Be alert for new or revised specifications that may affect the current manual guidance for contract administration. The mixed material shall be spread, shaped, and compacted in accordance with these specifications and in. This section provides guidelines for inspecting cement treated base ctb. Cta could be used in both flexible and rigid pavement structures. Service performance of cement treated bases as used in composite pavements ernest zube, c. The versatility of cement is critical to the success in this pavement solution because site conditions and soil types from gravel to clays can easily change during or between projects and cement acts as a universal stabilizer. Lreated base ctb pavements basically consist of a layer of. Cement treated base safety data sheet according to federal register vol.
Soil cement stabilization institute for transportation. The mixed material shall be spread and shaped with a. Determination of mechanical properties for cement treated. Pdf a study on cement treated base using crushed bricks as aggregate pritam debnath and mohini saha academia. It not only saves money but also helps to increase life cycle of roads. Evaluation and mix design of cementtreated base materials. Minimizing reflective cracking in cementstabilized. Various military agenciesdepartments army, air force, navy, marine corps also allow the use of. Cta consists primarily of base aggregate mixed with a specified percentage of hydraulic cement by weight and field compacted at moisture contents that are slightly greater than the optimum moisture content. Index terms cement treated sub base for bituminous pavement. This guide specification covers the requirements for portland cementstabilized base or subbase for airfields, roads and streets. Uses higher dosages of cement cement treated base ctb intended to create a structural base uses higher dosages of cement typically used for faa projects full depth reclamation fdr intended to create a structural base used widely to address existing pavement complete structural failures uses higher dosages. Final draft update of item p304 cementtreated base course 105 description 3041. More recently, those materials have been used as subbases to concrete pavings.
This test method does not purport to address all of the safety problems associated with its use. Cement treated base will be measured by the ton, cubic yard, or square yard as a composite mixture of cement, flexible base, and recycled materials. Microcracking for reduced shrinkage in cementtreated base. Cement treated base is a general term that applies to a mixture of native soils andor manufactured aggregates with measured amounts of portland cement and water that is compacted and cured to form a strong, durable, frostresistant paving material. The primary difference between ctb and soil cement is that ctb usually utilizes a graded aggregate instead of the native soils. The primary difference between ctb and soil cement is that ctb usually utilizes a graded aggregate instead of. A well designed, constructed, and properly maintained cement stabilized base will normally outlast several asphalt overlays, providing decades of low maintenance service.
Abstract reclaimed asphalt pavement rap and granular base materials were collected from stockpiles in six txdot districts to evaluate the feasibility of using high rap content mixes for base course applications. The higher stiffness provided by cementstabilized bases produces lower deflections, resulting in lower surface strains and. Mix and compact cement, water, and subgrade or base with or without asphalt concrete pavement in the roadway. Interpretation of geotechnical properties of cement treated soils. The completed ctb must be adequately cured to both let the cement hydrate. D020 partial panel concrete replacement 06202019 d521 trench repair reinforced concrete pavement 12202012 32 11 23 flexible base courses 12202012 32 11 29 lime treated base courses 12202012 32 11 33 cement treated base courses 08212015 32 11 37 liquid treated soil stabilizer 12202012 32 12 16 asphalt paving. Cement treatment of an aggregate base layer is an enhancement to the road foundation support when poor subgrade conditions are encountered. Non treated, 5%, and 10% cement treated soils displayed ductile, planar, and splitting type of failure, respectively. Factors that can influence shrinkage cracking in soil cement bases are. The contractor will not be allowed to use hydraulic rams on excavators that may damage the cement treated base below the pavement to be removed. For 10% cement treated soils pore pressures rose rapidly to confining pressure s resulting in zero effective confining pressure at failure. Cement treated base is an ideal solution for outdoor storage lots, parking lots, or industrial aggregate type yards. In cementtreated base construction the objective is to obtain a thorough mixture of an aggregategranular material with the correct quantity of portland cement and enough water to permit maximum compaction.
Guide to cementtreated base ctb 2 asphalt unstabilized cementstabilized figure 1. Ctb can be mixed inplace with onsite soils or mixed in a central plant or pugmill depending on the. This guide specification covers the requirements for portland cement stabilized base or subbase and lean concrete bases or subbases. Cement treated base ctb is a cement stabilized material which becomes more important to a modern road pavement under a better performance perspective. Ctb consists of native soils, gravels, or manufactured aggregates blended with prescribed quantities of cement and water. Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. Cement treated base is a mixture of aggregate material, granular soils combined with prescribed amounts of cement and water that hardens after compaction and curing to form a durable paving. The strength of cement treated aggregate base represented by california bearing ratio cbr and compressive strength with percent higher than those to base by 46% and 58% respectively. Cement modified soil cms is a soilaggregate material that has been treated with a relatively small proportion of portland cement in order to amend its undesirable properties so that they are suitable for use in subgrade or foundation construction. The work required for cement treated granular base and cement treated granular subbase is detailed in subsections 315.
Characterization and structural design of cementtreated base k. Notify the engineer of the proposed material sources and of changes to material. The contractor shall be solely responsible for the cement treated base either batched at andor delivered to the site. Cement modified soil cms is a soilaggregate material that has been treated with a relatively small proportion of portland cement in order to amend its undesirable properties so that they are suitable. The work provided shall include the furnishing, placement and compaction of one or more courses of plant mixed portland cement treated base course ctb to the lines, grades, dimensions, moisture, density and typical sections as specified in the plans and. Revised and simplified definition of lot size and partial lot in p401, p403, p501, and. Description mix and compact cement, water, and subgrade or base with or without asphalt concrete pavement in the roadway. Added new p307 cement treated permeable base course ctpb. The goal of microcracking is to prevent severe, wide. Section 27, cement treated bases, of the standard specifications provides requirements for placing ctba mix of aggregate, portland cement, and water.
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