The Foreman: 2015

How to repair damaged concrete

1) Honeycombing, especially severe honeycombing shall not be patched up without showing the conditions to the QA Engineer who would decide the remedy.

1) On removal of formwork, the surface shall be examined by Engineer. The inspection shall

liquid nitrogen concreting

1) In hot weather, (temperature of surrounding higher than 40 C) concrete shall be transported in deep containers to reduce the loss of water due to evaporation

For the assessment of compliance of ready-mixed concrete or site mixed concrete, the point and time of sampling shall be at discharge from the producer’s de

Vital steps for Concrete cube sampling

For Site Mixed Concrete:

The minimum frequency of cube casting shall be as follows

After concreting checks

1) All the flat portions of footings / underground structures shall be applied an epoxy based bituminous layer for protection against ground water.

Curing of shearwall , columns, slabs

Columns / Shear walls

1) Curing shall be done keeping the concrete surface wet by covering it with moist double Hessian cloth 2) Curing shall continue for at least 10 days.

Slabs
1) Curing of slabs shall be done as mentioned above.
2) Ponds shall be made within 24 hours of slab casting and till then slab shall be cured by spraying water.
3) Ponds shall be made at column locations first to cover from all sides and then to cover other portions of slab.
4) Care shall be taken to see to it that ponds are completely filled with water through out the recommended period for curing.
5) Vertical faces of the beams and area of slab out side ponds shall be cured by covering with wet Hessian cloth.
6) Incase where ponding is not done, whole slab should be covered with wet hessian cloth and care should be taken to keep it moist always.

Footings
1) Flat portion of footings shall be cured by covering it with wet double Hessian cloth.
2) For flat portions of Rafts, curing shall be done in a similar way as that for slab and vertical faces shall be cured similar to the columns.

How to protect fresh concrete

Protection of concrete

1) Newly placed concrete shall be protected from rain, sun and wind by approved means viz: Hessian cloth, plastic sheets etc.
2) Concrete placed below the ground level shall be protected against contamination from falling earth, during placing.
3) The area in and around the actual place of the concreting shall be kept sufficiently dry, by constructing sufficiently watertight forms / cofferdam around the area to be concreted, to prevent loss of mortar through walls.
4) Continuously dewatering the area through out the period of concreting and till initial set of concrete occurs with the help of dewatering pumps shall not be resorted to.

How to achieve concrete strength by curing

Curing

1) Curing is the process of preventing the loss of moisture from the concrete whilst maintaining a satisfactory temperature regime. For all concrete works, curing shall be start

types

Footings

1) PCC should be done in level as per given size in drawing with Dobra marking.

RCC - Ready Mix concrete checks

Ready Mix Concrete:

1) Transit trucks shall comply with the relevant code, with an agitating speed between 2 and 3 RPM and mixing speeds in the range of 10-20 RPM.
2) Before unloading of any truck at the site, the

RCC - How to make concrete at Site

I. Site Mixed Concrete:

site mixer

1) Weights of aggregates shall be adjusted in the first 5 batches to get required slump, without changing the water cement ratio given in the

RCC - During Concrete checks

During Concreting Checks

1) Before starting concrete for the day, the gradation of fine and coarse aggregate shall be checked and if any deviation in combined gradation is observed, necessary corrections in

Step 2 – Site Preparation

Dewatering of area to be concreted shall be carried out if required. Also area shall be cleaned of any dirt, debris, waste material, binding wires etc.

Step 3 – Pre Concreting Checks

15) All other requirements pertaining to Materials, Storage of Ingredients, production, delivery, batching equipments, quality control, sampling, order processing etc. as specified in IS 4926:2003 – “READY- MIXED CONCRETE-CODE OF PRACTICE” shall be binding on the producer / supplier of concrete.

RMC (part4) - Ready Mix Concrete

On site the following information will be added:

(a) Time of arrival on site.
(b) Time when discharge was completed.
(c) Any water / admixture added by the supplier to meet the specified workability.
(d) Any extra water or admixture added at the request of representative and his

slab pour self compacting concrete

Site representative with a preprinted delivery ticket for each delivery of concrete on which is printed, stamped or written the minimum information detailed below. The delivery ticket will form the basis of invoicing. The following information shall be included in the delivery ticket to accompany the load to engg

hose pour slab

3) Minimum Cement Content, Maximum Water Cement Ratio and Maximum Cement Content shall be as per the requirements of IS 456:2000 with respect to the exposure conditions specified there in.

4) Site Engg requirement of workability at the pump point as measured by slump test shall be between 140-160 mm, so that after pumping to the desired location the slump is minimum120 mm. Any concrete shall be designed for a minimum three hours retention/open time. The workability of the concrete shall be controlled on a continuous basis during production and any corrective action necessary taken. No additional water, other than the amount required to produce the specified grade of concrete as per mix design, shall be added to the truck mixer drum before discharge unless specifically requested and signed for representative.
Redosing or split dosing shall be allowed subject to the written permission of trained technicians and Engineers . In any case, the total dose should not exceed the maximum dose of admixture declared by Supplier or recommended by Admixture supplier. The supplier shall stock at least 50 litre of admixture with Quality Control department at site.
5) Any concrete poured should get finally set within maximum 24 hours.
6) Any concrete of a specified Grade shall meet the characteristic strength in 28 days. Any concrete being supplied to our site, which does not achieve minimum characteristic strength at 28 days, shall be considered as failure and no other acceptance criteria shall be entertained.
7) It is important to maintain the water cement ratio constant at its correct value. The amount of added water shall be adjusted to compensate for any observed variations in the moisture contents in the aggregates. Suitable adjustments should also be made in masses of the aggregates due to this variation. Any change in water content due to change in aggregate grading shall be taken care of by forward control by suitable modifications to mix design.
8) Batch sheets, moisture correction calculation/sheet shall be submitted along with challans for every pour of concrete. The scope of addition of extra admixture (over and above the quantity which has already been added at the time of batching at plant) shall be declared by concrete supplier. Immediately before discharging the concrete at the point of delivery, the producer or his representative shall provide

Important points for backfilling

Important points for backfilling

1) Backfilling work shall not start until Site Engineer gives his approval to do so. Material used for backfilling shall be any one or combination of soil types mentioned

Antitermite Treatment to plinth and external perimeter of building

Antitermite Treatment to plinth and external perimeter of building:

1) Treatment shall also be given over the entire plinth area prior to laying PCC. Recommended dosage is 5 litres / sq. m of area to be treated.

Antitermite treatment during backfilling

Antitermite treatment during backfilling

1) Antitermite solution being highly poisonous as well as inflammable, utmost care shall be taken during their handling. Wearing of hand gloves to avoid skin contact as also wearing of masks to avoid inhalation is recommended.

Post Excavation Procedures

Post Excavation Procedures:

Antitermite Treatment to sides of excavated pits:

1) Antitermite treatment solution shall be prepared on site by mixing solution mentioned.

2) Antitermite treatment in foundation shall start after site Engineer gives his permission to do so. Treatment shall be complete with treatment of soil underneath the foundation as well as to the sides of the excavated pits to form a total barrier between foundation and excavated pits.

precaution to be taken blasting operation

Following precaution shall be taken blasting operation:

a) Area within minimum distance of 150m from the region to be blasted shall be evacuated. Boundaries of the area to be blasted shall be guarded by minimum 4 persons who in turn shall wave red flags on the boundary to prevent entry of personnel during blasting operation. Signal shall be given before and after blasting.

b) It shall be ensure that all charges have exploded by counting number of charges to fired and actual number of shots heard.

c) Misfires, if any, shall be brought to the notice of Consultant / Project Manager and necessary remedial measure shall be taken as per Consultant’s advice.

Important Points During Excavation Procedure

During Excavation Procedures:

1) The excavation shall be done to correct lines, dimensions and levels as per drawing. Adequate side slopes shall be maintained during excavation of loose soil to prevent soil from sides of excavated pits from falling back into the pits.

2) Wherever required, proper shoring and strutting shall be provided to maintain and prevent sides of excavations from collapsing.

3) No heavy equipment shall be allowed within 6m from edge of excavation or within a distance equal to depth of excavation, whichever is less.

shoring & strutting

Excavation:

1) It shall be ensured that all necessary equipments, tools, instruments, material and consumables including temporary facilities like platform, walkways etc. as mentioned are available at site.

2) All skilled / unskilled manpower along with supervisory personnel for carrying out work shall have sufficient experience on similar works.

(how to) Procedures for Excavation and backfilling works including Antitermite Treatment

Procedures for Excavation and backfilling works including Antitermite Treatment

Pre Excavation Procedures:

Setting out:

1) It shall be ensured that drawing indicating setting out points is available on site. Also necessary surveying equipment as mentioned shall be available on site in good operational condition.

(backfill) Storage of Raw Material

C) Storage of Raw Material

a) Soil for backfilling:

1) Excavated materials which in the opinion of Site Engineer are useful shall be stacked in regular heaps, bunds with regular slopes. Such stacking shall be done within the lead (50 m or as specified).

2) Stacks of soil shall be properly leveled for providing natural drainage.

Guidelines for Inspection of Backfill Material

Even though hard murum is to be used as a back fill soil ideally, it should meet the following

inserting gelatine

pressure drill rod

high performance gelatine

air pressure drill

D) Blasting operation consumables:

a) Various blasting operation consumables shall be either or combination of following: 1) Gunpowder
2) Dynamite

Anti termite spraying

B) Water:

By mere observation, water should be clean and free from dirt and organic matter. Waste (treated) water from STP can be considered suitable for compaction of backfill material.

(Part 1) Excavation and Backfilling with Antitermite Treatment

Raw Materials, their Inspection and Acceptance Criteria

A) Soil used for backfilling:

JCB backhoe loader

1) Murrum: - Murrum for backfilling shall be freshly excavated, free from vegetation, boulders, silt and clay. Murrum can be either hard or soft.

How to repair damaged concrete

Inspection of concrete after removal of formwork and Corrective Measures

Hot / Cold Weather Concreting Requirements

Steps for Casting and testing of Cubes