CN103758344A - Control method preventing concrete cracks - Google Patents

Abstract

The invention relates to a control method preventing concrete cracks. The control method includes the steps: 1) reasonably configuring structural reinforcements in structural design before construction and preventing the cracks; 2) selecting and matching concrete materials by doping coal ash or high-effect water reducing agents in concrete; 3) removing seepage and water and bubbles inside the concrete by the aid of vertical vibrated concrete, secondary vibrating and secondary plastering technology. The method solves the technical problem that the concrete easily cracks, fine effects are achieved, and the quality of a concrete product is improved.

Description

The control method of crack preventing

Technical field

The present invention relates to the control method of a kind of construction method, particularly a kind of crack preventing.

Background technology

Concrete is a kind of heterogeneous brittle material being formed by sandstone aggregate, cement, water and the mixing of other admixtures.Due to series of problems such as concrete construction and distortion itself, constraints, in the concrete of hardened forming, exist numerous micropores, air pocket and microcrack, during concrete in mass sclerosis, to discharge a large amount of heats of hydration, cause concrete internal temperature too high, often occur a lot of cracks.

Microcrack does not produce harm to concrete load-bearing, antiseepage and some other use function, but after being subject to the effects such as load, the temperature difference at concrete, microcrack will constantly be expanded and be communicated with, and finally forms macroscopic crack.When the width of distress in concrete surpasses the limit value of regulation, can affect applicability and the durable flight of steps leading to a palace hall of building and member, not only damage image appearance, also can cause reinforcing steel bars exposed, corrode and reduce the ability of building structure opposing load, reduce globality and the rigidity of building structure.

Summary of the invention

The object of this invention is to provide a kind of control method that can crack preventing.

In order to realize above-mentioned object, the control method of crack preventing of the present invention comprises the following steps:

1) reasonable disposition distributing bar in the structure design before construction, prevents the generation in crack;

2) selection of concrete raw material and proportioning: adding coal ash or high efficiency water reducing agent in concrete;

3) adopt vertical vibrated concrete, adopt secondary vibration, quadric-plastering technology, to get rid of moisture and the bubble of bleeding, inside concrete.

Described concrete vibrating time is 8s～10s.

In described concrete, adopt large particle diameter aggregate

The inventive method has solved concrete and has easily produced the technical problem in crack, has good effect, has improved the quality of concrete products.

The specific embodiment

Control method of the present invention is as follows:

Before construction, carry out design and preparation:

Handle the structure design under restrained condition well, when structure does not have enough distortion leeway, reasonable disposition distributing bar in structure design, prevents the generation in crack.

Should avoid the stress that structure section sudden change brings to concentrate as far as possible, as because of structure or moulding reasons etc. at a puss, should take into full account strengthening measures such as adopting constructional reinforcement; Active adoption expansive concrete technology.

As far as possible rationally and scientifically arrange each work post cross-operation time properly, after reinforcement colligation, spool is pre-buried to be sealed before edge is received head and should intert in time and strive for completing comprehensively with template, accomplishes not stay or leave loose ends less, effectively to reduce the operating personnel's quantity after plate face reinforcing bar binding.

Concrete worker is when building, and the easy happening part of fracture and negative bending moment rib region, should lay interim shifting stage, expands contact surface, and dispersive stress, avoids top reinforcement to be subject to again trampling distortion as possible.

Focus on selection and the proportioning of concrete raw material:

If adopt the larger aggregate of absorptivity in concrete, drying shrinkage is large, aggregate mud content is when more, can increase concrete drying shrinkage; Aggregate size is large, grating is when good, due to the cement paste consumption that can reduce in concrete, so concrete dry shrinkage is less.

Adding coal ash can reduce cement consumption and effectively reduce the heat of hydration, can reduce concrete folk prescription water supply volume and cement consumption, also can reduce concrete own vol and shrink.

Meanwhile, in concrete, adding coal ash or high efficiency water reducing agent can not only make concrete have good workability, pumpability, impermeability, anti-segregation well, reduce excreting water phenomenon concrete surface processing occurs, is conducive to.According to the requirement of strength grade of concrete and quality inspection and concrete workability, determine match ratio, strictly control water/binder ratio and cement consumption.

Select the good stone of grating, control particle diameter and the content of sand, reduce void content to reduce concrete shrinkage amount, improve agent on crack resistance of concrete resistance to spalling.

Reinforcing concrete waters the requirement of the work of smashing:

Water vibrating head suggestion employing while smashing and vertically vibrate, housing in row is arranged, and accomplishes to insert and pull out slowly soon, according to different concrete slumps, correctly grasp vibrating time, avoided shaking or leaked and shook, and should advocate and adopt secondary vibration, quadric-plastering technology, to get rid of moisture and the bubble of bleeding, inside concrete.

Due to freely trickling of a lot of pumping of concrete, form concrete placement layer by layer.When vibrating last layer, should insert in lower one deck, to eliminate the seam of two-layer centre, the concrete self-assembling formation thickness of last layer can not surpass 1.25 times of vibrating head length.

Concrete vibrating time is unsuitable long, is generally 8s～10s, to prevent that stone from sinking to causing concrete structure inhomogeneous.Concrete casting is during to surface layer, and screeding and compaction is answered on surface, to get rid of moisture and the bubble of bleeding, inside concrete, to improve concrete compactness.The position of forbidding concrete to be scattered in not yet to build, in order to avoid form potential cold seam or weak spot.Concrete casting is during to surface layer, and screeding and compaction is answered on surface, to get rid of moisture and the bubble of bleeding, inside concrete, to improve concrete compactness quadric-plastering technology, to get rid of moisture and the bubble of bleeding, inside concrete.Due to freely trickling of a lot of pumping of concrete, form concrete placement layer by layer.

When vibrating last layer, should insert in lower one deck, to eliminate the seam of two-layer centre, the concrete self-assembling formation thickness of last layer can not surpass 1.25 times of vibrating head length.Concrete vibrating time is unsuitable long, is generally 8s～10s, to prevent that stone from sinking to causing concrete structure inhomogeneous.Concrete casting is during to surface layer, and screeding and compaction is answered on surface, to get rid of moisture and the bubble of bleeding, inside concrete, to improve concrete compactness.The position of forbidding concrete to be scattered in not yet to build, in order to avoid form potential cold seam or weak spot.Concrete casting is during to surface layer, and screeding and compaction is answered on surface, to get rid of moisture and the bubble of bleeding, inside concrete, to improve concrete compactness.

Above-described embodiment does not limit the present invention in any way, and every employing is equal to replaces or technical scheme that the mode of equivalent transformation obtains all drops in protection scope of the present invention.

Claims (3)

1. a control method for crack preventing, is characterized in that comprising the following steps: 1) reasonable disposition distributing bar in the structure design before construction, prevents the generation in crack;

2) selection of concrete raw material and proportioning: adding coal ash or high efficiency water reducing agent in concrete;

3) adopt vertical vibrated concrete, adopt secondary vibration, quadric-plastering technology, to get rid of moisture and the bubble of bleeding, inside concrete.

2. the control method of crack preventing according to claim 1, is characterized in that: described concrete vibrating time is 8s～10s.

3. the control method of crack preventing according to claim 1, is characterized in that: in described concrete, adopt large particle diameter aggregate.