Whole structure of cast-in-place construction of lightweight aggregate concrete (template)
1 scope
The technology standard is applicable to on-site mixing the ceramsite, pumice lightweight aggregate, lightweight aggregate concrete pouring ordinary sand full cast-in-place template engineering.
2 construction preparation
2.1 material and main equipments:
2.1.1 lightweight aggregate:
Mr. Fu: maximum particle size should not be greater than 20 mm, not allowed to contain more than double the biggest diameter of particles. Grading requirements by 5 mm mesh is not more than 90%, by 10 mm mesh is 30% ~ 30%; By 200 mm mesh is not greater than 10%. Void ratio is not greater than 50%, bibulous rate is 1 h than not greater than 25%, silt content is not more than 2%, loose density, compressive strength comply with the design requirements.
Ceramsite: same as the above requirements, and shall not be mixed inclusion or clay.
2.1.2 sand, medium sand and coarse sand and silt content when the concrete strength grade is C10 ~ C30, no greater than 5%, when the concrete strength grade is greater than the C30, no greater than 3%.
2.1.3 cement: 325 #, 425 # slag Portland cement and ordinary Portland cement.
2.1.4 admixture: product quality certification, the content must be determined by laboratory, technical performance in accordance with the provisions of the relevant standards.
2.1.5 main machine, mixer, skip, trolleys, the scale, internal vibrator, shovels, iron plate, wood trowel, xiaoping spade, small spoon, bucket, rubber hoses, admixture containers, etc.
2.2 operation conditions:
2.2 l raw materials such as cement, lightweight aggregate, admixture check factory certificate comes into play, its technical performance indicators must conform to the requirements, the lightweight aggregate, and the reinspection do not coincide in every 2003 for a batch (less than 200 m3 by a number of), must be inspection: loose density, grain size distribution, the strength of cylinder pressure, the water absorption of 1 h. Natural lightweight aggregate, inspection of hydraulic, the reinspection is unqualified, should find out the reason and take action.
2.2.2 trial with laboratory, and to determine the distribution ratio, slump. The strength of lightweight aggregate concrete, the density shall comply with the design requirements.
2.2.3 lightweight aggregate yard should have drainage measures, keep as far as possible when using particle mixing, avoid size particle separation, according to the size distribution of the natural stacked, its height should not be more than 2 m, to prevent the leaves, dirt or other harmful substances into.
2.2.4 template flat-fell seam should be tight, if using wood pattern, water must be wet. Exterior wall outside the big template mode of mouth ring beam position should have the measures to prevent slurry.
2.2.5 construction before familiar with the design requirements of drawings, technical clarificaiton.
3 operation process
3.1 the process flow
Homework to prepare to material measurement to mixing, transportation, casting - vibro - maintenance
Material measuring 3.2: aggregate, cement, admixtures and water are calculated by weight, aggregate measurement deviation should be allowed is less than + / - 3%, cement, water and additive measurement deviation should be allowed is less than + / - 2%, lightweight aggregate appropriate prewetting before mixing, so according to mix water, still must calculate water content of aggregate (mixing) should be determined before the aggregate moisture content, make a corresponding adjustment, often should parking in the process of mixing, rainy days or slump exceptions should be timely determination of moisture content, adjust the water consumption. Water cement ratio total available water cement ratio, said of proportion of the total water consumption should include effective water and two parts of the lightweight aggregate lh water quantity.
3.3 stir:
3.3.1 sequence: using the mixer add 1/2 of the first water. Then add the thickness of aggregate and cement, stir for 1 min, add the remaining water, stir not less than 2 min. Using forced mixer, and fine aggregate, cement and aggregate, stir for 1 min, then add water continued to stir not less than 2 min.
3.3.2 rainfall distribution on 10-12 stirring time: should be slightly longer than ordinary concrete, the mixing time is about 3 min. In the mixing process of lightweight aggregate concrete, lightweight aggregate to absorb moisture, therefore, appropriate is used in the construction of slump value to control the water consumption of concrete, and control the water cement ratio, it is practical in easy to master.
3.4 shipping: in the early lightweight aggregate absorbent ability is very strong, so should try to shorten the concrete in the construction by the mixer for export to operation casting the process time, generally no more than 45 min. Appropriate USES skip of blender discharging mouth hanging directly to the surface pouring, avoid or reduce midway transship, if lead to poor mixture workability, slump variable hours, appropriate artificial secondary mixing before casting.
3.5 casting: should be continuous construction, leaving no or less construction joints, concrete should be layered, for big project template, each layer of casting the first layer height should not exceed 50 cm, after every time not more than lm, if leave construction joints should be vertical at external junction and water segment boundaries, net lead wire or plug template, continue before construction, joint must be clean, water wet, and then pouring concrete.
3.6 vibrating: lightweight aggregate density light, so easy to cause mortar sinking, lightweight aggregate to rise. Internal vibrator faster slowly pull, point to the appropriate encryption, uniform distribution, the vibrating spacing is less than common concrete spacing, vibrating effect should not be greater than the radius of 1 times, insert depth should not be more than casting height. Vibration time shoulds not be too long, to prevent the layered segregation. Press the exposed lightweight aggregate concrete surface with tools into the mortar, the flat surface with wood float away and.
3.7 maintenance: form removal strength of lightweight aggregate concrete under the normal temperature should be greater than 1 mpa. After dismantle wet curing or covering film wet maintenance in time, prevent water loss from dry shrinkage crack. Full cast-in-place wall outside big template using triangle bracket, exterior wall concrete strength control is not lower than 7.5 MPa, ensure the safety of the triangle bracket.
Winter of winter construction: 3.8 according to the plan execution.
3.8.1 shall not use aggregate with ice and snow and frozen cake.
3.8.2 to transport the containers should be concrete heat preservation measures.
3.8.3 winter water prewetting, lightweight aggregate impossible when using natural air-dry condition of lightweight aggregate, should adjust slump control values, generally take 12 ~ 14 cm, than the room temperature increases 4 ~ 6 cm, the concrete tank after the transportation to the site of the pouring down to about 8 to 10 cm, can guarantee a vibratory compaction of concrete, and can control the concrete due to the large plastic deformation, surface of coarse aggregate, and segregation phenomenon.
3.8.4 mixing pumice concrete can be used on the secondary materials, secondary mixing method. First feeding on pumice, admixture (fly ash) and a third of the water and stir 1 min, the second feeding adding cement, sand, admixture and its Yu Deshui for stirring, so as to improve the workability of concrete, and avoid the pumice hole absorb admixture.
3.8.5 wall template to dismantle and hang a tripod, strength of concrete is needed to block with conditions. The intensity control according to 4 MPa and 7.5 MPa, respectively. To ensure that the concrete mixed with antifreeze cold security when critical strength and hang a tripod.
4 quality standards
4.1 ensure projects:
4.4.1 of lightweight aggregate concrete using cement, aggregate, admixture, mixture, metering, mixing, maintenance and construction joint treatment, must accord with the requirement of construction specifications and relevant standards, inspection certificate and test report.
4.2.2 lightweight aggregate concrete strength meet the requirements of the design and test evaluation standard density comply with the design requirements.
4.2 the basic items:
Should be vibrating close-grained, surface of voids, pits, not exposure, no holes and cracks slag layer.
4.3 allowable deviation projects, see table 4-33.
Table 4 -
Allowable deviation (mm)
Much higher layer
1 the axis displacement 8 5 'quantity check
High layer plus or minus 10 + 10
All high plus or minus 30 plus or minus 30
Dimensions 3 + 5 + 5-2-2 feet quantity check
Each layer of 5 5 in 2 m line board check
Overall height 1 ‰ and 20 ‰ and 30 or less or less quantity check with theodolite or messenger wire and ruler
5 surface is flat and level 4 4 in 2 m by feet and wedge feeler check
Embed steel centerline offset 10 10 6
7 embedded pipe, hole, embedded bolt axis offset May 5
8 the reserved hole centerline offset 15 15
5 finished product protection
5.1 protect the hole when casting, vibrating, embedded parts and water, electricity embedded pipe, box, etc.
5.2 to approach of lightweight aggregate shall be properly kept, prevent breakage and mixed with sundry.
5.3 when completed, the concrete pouring and vibrating and keep showing reinforced location is correct.
6 should pay attention to quality problems
6.1 unstable concrete slump: water control, a change in the moisture content of lightweight aggregate, the timely adjustment of water.
6.2 poor workability, stirring time, discharging too fast.
6.3 lightweight aggregate on the surface of the leakage: concrete vibratory head, plus the vibrating surface, nor to take pressure, smooth.
6.4 low intensity: inaccurate measurement, vibrating close-grained, not bad maintenance.
6.5 pick up if not compacted: external ring beam joint if parts shall not leak slurry, pay attention to the vibrating compaction.
7 quality records
This technology standard should have the following quality records:
7.1 materials (cement, sand, lightweight aggregate, admixture, etc.) factory qualified certificate, test report.
7.2 lightweight aggregate concrete block test reports, strength assessment.
7.3 concrete construction records.
7.4 kinds of construction quality test evaluation.
7.5 inspection and engineering records.
7.6 winter construction records.
7.7 design change, regarding the record.
7.8 other technical documents.
1 scope
The technology standard is applicable to on-site mixing the ceramsite, pumice lightweight aggregate, lightweight aggregate concrete pouring ordinary sand full cast-in-place template engineering.
2 construction preparation
2.1 material and main equipments:
2.1.1 lightweight aggregate:
Mr. Fu: maximum particle size should not be greater than 20 mm, not allowed to contain more than double the biggest diameter of particles. Grading requirements by 5 mm mesh is not more than 90%, by 10 mm mesh is 30% ~ 30%; By 200 mm mesh is not greater than 10%. Void ratio is not greater than 50%, bibulous rate is 1 h than not greater than 25%, silt content is not more than 2%, loose density, compressive strength comply with the design requirements.
Ceramsite: same as the above requirements, and shall not be mixed inclusion or clay.
2.1.2 sand, medium sand and coarse sand and silt content when the concrete strength grade is C10 ~ C30, no greater than 5%, when the concrete strength grade is greater than the C30, no greater than 3%.
2.1.3 cement: 325 #, 425 # slag Portland cement and ordinary Portland cement.
2.1.4 admixture: product quality certification, the content must be determined by laboratory, technical performance in accordance with the provisions of the relevant standards.
2.1.5 main machine, mixer, skip, trolleys, the scale, internal vibrator, shovels, iron plate, wood trowel, xiaoping spade, small spoon, bucket, rubber hoses, admixture containers, etc.
2.2 operation conditions:
2.2 l raw materials such as cement, lightweight aggregate, admixture check factory certificate comes into play, its technical performance indicators must conform to the requirements, the lightweight aggregate, and the reinspection do not coincide in every 2003 for a batch (less than 200 m3 by a number of), must be inspection: loose density, grain size distribution, the strength of cylinder pressure, the water absorption of 1 h. Natural lightweight aggregate, inspection of hydraulic, the reinspection is unqualified, should find out the reason and take action.
2.2.2 trial with laboratory, and to determine the distribution ratio, slump. The strength of lightweight aggregate concrete, the density shall comply with the design requirements.
2.2.3 lightweight aggregate yard should have drainage measures, keep as far as possible when using particle mixing, avoid size particle separation, according to the size distribution of the natural stacked, its height should not be more than 2 m, to prevent the leaves, dirt or other harmful substances into.
2.2.4 template flat-fell seam should be tight, if using wood pattern, water must be wet. Exterior wall outside the big template mode of mouth ring beam position should have the measures to prevent slurry.
2.2.5 construction before familiar with the design requirements of drawings, technical clarificaiton.
3 operation process
3.1 the process flow
Homework to prepare to material measurement to mixing, transportation, casting - vibro - maintenance
Material measuring 3.2: aggregate, cement, admixtures and water are calculated by weight, aggregate measurement deviation should be allowed is less than + / - 3%, cement, water and additive measurement deviation should be allowed is less than + / - 2%, lightweight aggregate appropriate prewetting before mixing, so according to mix water, still must calculate water content of aggregate (mixing) should be determined before the aggregate moisture content, make a corresponding adjustment, often should parking in the process of mixing, rainy days or slump exceptions should be timely determination of moisture content, adjust the water consumption. Water cement ratio total available water cement ratio, said of proportion of the total water consumption should include effective water and two parts of the lightweight aggregate lh water quantity.
3.3 stir:
3.3.1 sequence: using the mixer add 1/2 of the first water. Then add the thickness of aggregate and cement, stir for 1 min, add the remaining water, stir not less than 2 min. Using forced mixer, and fine aggregate, cement and aggregate, stir for 1 min, then add water continued to stir not less than 2 min.
3.3.2 rainfall distribution on 10-12 stirring time: should be slightly longer than ordinary concrete, the mixing time is about 3 min. In the mixing process of lightweight aggregate concrete, lightweight aggregate to absorb moisture, therefore, appropriate is used in the construction of slump value to control the water consumption of concrete, and control the water cement ratio, it is practical in easy to master.
3.4 shipping: in the early lightweight aggregate absorbent ability is very strong, so should try to shorten the concrete in the construction by the mixer for export to operation casting the process time, generally no more than 45 min. Appropriate USES skip of blender discharging mouth hanging directly to the surface pouring, avoid or reduce midway transship, if lead to poor mixture workability, slump variable hours, appropriate artificial secondary mixing before casting.
3.5 casting: should be continuous construction, leaving no or less construction joints, concrete should be layered, for big project template, each layer of casting the first layer height should not exceed 50 cm, after every time not more than lm, if leave construction joints should be vertical at external junction and water segment boundaries, net lead wire or plug template, continue before construction, joint must be clean, water wet, and then pouring concrete.
3.6 vibrating: lightweight aggregate density light, so easy to cause mortar sinking, lightweight aggregate to rise. Internal vibrator faster slowly pull, point to the appropriate encryption, uniform distribution, the vibrating spacing is less than common concrete spacing, vibrating effect should not be greater than the radius of 1 times, insert depth should not be more than casting height. Vibration time shoulds not be too long, to prevent the layered segregation. Press the exposed lightweight aggregate concrete surface with tools into the mortar, the flat surface with wood float away and.
3.7 maintenance: form removal strength of lightweight aggregate concrete under the normal temperature should be greater than 1 mpa. After dismantle wet curing or covering film wet maintenance in time, prevent water loss from dry shrinkage crack. Full cast-in-place wall outside big template using triangle bracket, exterior wall concrete strength control is not lower than 7.5 MPa, ensure the safety of the triangle bracket.
Winter of winter construction: 3.8 according to the plan execution.
3.8.1 shall not use aggregate with ice and snow and frozen cake.
3.8.2 to transport the containers should be concrete heat preservation measures.
3.8.3 winter water prewetting, lightweight aggregate impossible when using natural air-dry condition of lightweight aggregate, should adjust slump control values, generally take 12 ~ 14 cm, than the room temperature increases 4 ~ 6 cm, the concrete tank after the transportation to the site of the pouring down to about 8 to 10 cm, can guarantee a vibratory compaction of concrete, and can control the concrete due to the large plastic deformation, surface of coarse aggregate, and segregation phenomenon.
3.8.4 mixing pumice concrete can be used on the secondary materials, secondary mixing method. First feeding on pumice, admixture (fly ash) and a third of the water and stir 1 min, the second feeding adding cement, sand, admixture and its Yu Deshui for stirring, so as to improve the workability of concrete, and avoid the pumice hole absorb admixture.
3.8.5 wall template to dismantle and hang a tripod, strength of concrete is needed to block with conditions. The intensity control according to 4 MPa and 7.5 MPa, respectively. To ensure that the concrete mixed with antifreeze cold security when critical strength and hang a tripod.
4 quality standards
4.1 ensure projects:
4.4.1 of lightweight aggregate concrete using cement, aggregate, admixture, mixture, metering, mixing, maintenance and construction joint treatment, must accord with the requirement of construction specifications and relevant standards, inspection certificate and test report.
4.2.2 lightweight aggregate concrete strength meet the requirements of the design and test evaluation standard density comply with the design requirements.
4.2 the basic items:
Should be vibrating close-grained, surface of voids, pits, not exposure, no holes and cracks slag layer.
4.3 allowable deviation projects, see table 4-33.
Table 4 -
Allowable deviation (mm)
Much higher layer
1 the axis displacement 8 5 'quantity check
High layer plus or minus 10 + 10
All high plus or minus 30 plus or minus 30
Dimensions 3 + 5 + 5-2-2 feet quantity check
Each layer of 5 5 in 2 m line board check
Overall height 1 ‰ and 20 ‰ and 30 or less or less quantity check with theodolite or messenger wire and ruler
5 surface is flat and level 4 4 in 2 m by feet and wedge feeler check
Embed steel centerline offset 10 10 6
7 embedded pipe, hole, embedded bolt axis offset May 5
8 the reserved hole centerline offset 15 15
5 finished product protection
5.1 protect the hole when casting, vibrating, embedded parts and water, electricity embedded pipe, box, etc.
5.2 to approach of lightweight aggregate shall be properly kept, prevent breakage and mixed with sundry.
5.3 when completed, the concrete pouring and vibrating and keep showing reinforced location is correct.
6 should pay attention to quality problems
6.1 unstable concrete slump: water control, a change in the moisture content of lightweight aggregate, the timely adjustment of water.
6.2 poor workability, stirring time, discharging too fast.
6.3 lightweight aggregate on the surface of the leakage: concrete vibratory head, plus the vibrating surface, nor to take pressure, smooth.
6.4 low intensity: inaccurate measurement, vibrating close-grained, not bad maintenance.
6.5 pick up if not compacted: external ring beam joint if parts shall not leak slurry, pay attention to the vibrating compaction.
7 quality records
This technology standard should have the following quality records:
7.1 materials (cement, sand, lightweight aggregate, admixture, etc.) factory qualified certificate, test report.
7.2 lightweight aggregate concrete block test reports, strength assessment.
7.3 concrete construction records.
7.4 kinds of construction quality test evaluation.
7.5 inspection and engineering records.
7.6 winter construction records.
7.7 design change, regarding the record.
7.8 other technical documents.
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