concrete tech

  What is AAC Block Autoclaved Aerated Concrete is A light weight, and high insulating Durable building product, which is produced wide Range size strength ,AAC block light weight compare to CC bricks and red bricks, AAC block is different and CC block is different. Mortar Thickness :-  Keep it limited to 10mm to 12mm with regular cement mortar and 3mm to 4mm with ready made jointing mortar. Watering Block :- Before application the motor Dip block in water and lift immediately or reply water with brush. Curing of Masonry : - Curing Required only for cement mortar joint and not required for ready made mortar joint. Cutting block :-  Used tool like hacksaw or rotary cutter Plaster : -   Minimum external plaster thickness Will be 12mm to 15 mm and internal 10mm to 12mm. Advantage of AAC Block:-    The AAC block help in quick quick construction work there by reducing time and construction cost. AAC block easy to cutting block and used ordinary tools. AAC block is fire resistance 2 hours t

 1:2:4 concrete mix calculator concrete mix1:2:4 mins one is cement and two is sand(fine aggregate) and 4 is stone chip (coarse aggregate) coarse aggregate is two type 10mm and 20mm , 10mm will be 40 percentage and 20mm will be 60 percentage (for batter mixing) 1 cum wet volume =1.53cum dry volume Ratio is 1:2:4=1+2+4=7 cement :  1/7x1.53=0.22/0.035=6.24 Bag =313 kg (cement unit volume 1450=50/1450=0.035) Sand (fine aggregate): 1/7x1.53x2=0.44 cum=15.43cft Coarse aggregate: 1/7x4x1.53=0.87 cum = 30.87 cft 10mm :  0.87x0.40=0.35cum = 12.28cft 20mm : 0.87x 0.60=0.522 cum =18.43cft Water : water cement ratio as per IS 456 0.45 to 0.6 . we  assume 0.5 if plasticizer is not provided=313x0.5=156.5liter (slump maintain for 100mm , if water cement ratio is more and give strength is less so maintain minimum water cement ratio) if plasticizer is used then it will be 0.8 percent of cement =0.008x313 =2.54 liter Note: it is nominal mix M20 grade , its not design mix This type of nominal mix are u

Brick work calculation in feet 1 cum brick work and brick size is (230 x 120 x 75) 1cum Bricks equal to 77 percentage Bricks and 23 percentage mortar 1cum brick=0.77+0.23 So, number of bricks =0.77/(0.23x0.120x0.075) =370 Nos Mortar Ratio 1:6 1cum wet mortar is equal to dry volume=1.33 so that 0.23 cum wet volume =0.23x1.33=0.31 cum Ratio is 1:6 =1+6=7 Cement: (1/7)x0.31=0.044/0.035=1.27 Bag (64 kg) (cement unit weight is 1450=50/1450=0.035) Sand: (1/7)x0.31x6=0.266 cum=9.38 cft Mortar Ratio 1:5 1cum wet mortar is equal to dry volume=1.33 so that 0.23 cum wet volume =0.23x1.33=0.31 cum Ratio is 1:5 =1+5=6 Cement:  (1/6)x0.31=0.052/0.035=1.48 Bag (74kg) (cement unit weight is 1450=50/1450=0.035) Sand:  (1/6)x0.31x5=0.26 cum= 9.18 cft Mortar Ratio 1:4 1cum wet mortar is equal to dry volume=1.33 so that 0.23 cum wet volume =0.23x1.33=0.31 cum Ratio is 1:4 =1+4=5 Cement:  (1/5)x0.31=0.062/0.035=1.77 Bag (89kg) (cement unit weight is 1450=50/1450=0.035) Sand:  (1/5)x0.31x4 =0.248 cum= 8.75c

Type of cement in india  Cement: The cement used shall be any of the following and the type of selected should be appropriate for the intend use : 33 Grade ordinary Portland cement conforming to IS 269 43 Grade ordinary Portland cement conforming to IS 8112 53 grade ordinary Portland cement conforming to IS12269 Rapid hardening Portland cement conforming to IS 8041 Portland slag cement conforming to IS 455 Portland pozzolana cement (calcined clay based) conforming to IS 1489(part2) Hydrophobic Cement conforming to IS 8043 Low heat Portland cement confirming to IS 12600 Sulphate  Resisting port land cement confirming to IS 12330      Minaral admixture  pozzolanas : pozzolanic material confirming to relevant Indian standards may be used with the permition of the engineer in charge provided uniform blending with cement is insured  Fly ash : fly ash confirming 1 of IS 3812 may be used part replacement of ordary nary port land cement provided uniform blended cement is ensured  Silica fume:

 Number of cubes for concrete as per is code The minimum frequency of sampling of concrete of the each grade shall be in accordance with the following Quantity of concrete in the work in m 3 Number of sample 1-5 1 6-15 2 16-30 3 31-50 4 51 and above 4 plus one additional sample for each additional 50m 3      Characteristic Compressive Strength Compliance Requirement : Specified grade Mean of the group of 4 non-overlapping consecutive test results in N/mm 2 Individual test results in N/mm 2 M-15 >= fck + 0.825 x established standard deviation (rounded off to nearest 0.5 N/mm 2 ) or fck + 3 N/mm 2 whichever is greater >=fck – 3 N/mm 2 M-20 or above >= fck + 0.825 x established standard deviation (rounded off to nearest 0.5 N/mm 2 ) or fck + 4 N/mm 2 whichever is greater >= fck – 4 N/mm 2 Note : at least one sample taken

Soil compaction test by core cutter method         The most common Laboratory test is soil compaction test , as per CPWD specification soil compaction every 25cm per layer .For building compaction required above 95% and road 98% Procedure of compaction      Weight of core-cutter+ wet soil (Ws) in g Weight of core-cutter (wc) in g Weight of wet soil (Ws-Wc) Volume of core-cutter (Vc) in cm3 bulk density Ɣb=Ws-Wc/Vc Water content container no Weight of container with lid(W1) in g Weight of container with lid and wet soil (w2) in g Weight of container with lid and dry soil(W3) in g Water content (w) in percent w=(W2-W3)/(W3-W1) Dry density Ɣd=(100*Ɣb)/(100+w) Percentage of compaction Cp=Dry density(Ɣd)/Max Dry density(MDD) Example:  Weight of core-cutter+ wet soil (Ws) in g                                                             = 3000 Weight of core-cutter (wc) in g                                                                              = 983               Weight of wet soil (Ws