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BAI 1 :XAC NH KHOI LNG RIENG CUA XIMANG CAT

XAC NH KHOI LNG THE TCH CUA XIMANG

CAT

A GACH AT SET NUNG

MU C CH TH NGHIEM : Lam quen vi phng phap va thao tac th nghiem xac nh hai ch tieu vat

ly c ban ( khoi lng rieng va khoi lng the tch ) cua cac vat lieu:ximang, cat, a, gach at set nung.

Xac nh khoi lng rieng va khoi lng the tch cua mot so loai vat lieu le ta c th a vao cac ng dung nh: tnh toan d tru vat lieu cho cong

trnh, tnh toan kho cha va phng tien van chuyen, tnh cap phoi betongv.v Trong qu trnh bo qun, ximng ht m v dn vn cc nn cn phi xc

nh li khi lng th tch ximng1. TH NGHIEM XAC NH KHOI LNG RIENG :

Khoi lng rieng cua vat lieu la khoi lng cua mot n v the tch vat lieu tra ngthai hoan toan ac.

Cong thc tnh ton:

a

a

m

V (1-1)

Trong o:a : la khoi lng rieng cua vat lieu, n v (g/cm 3; kg/m3; tan/m3)

m : la khoi lng cua vat lieu trang thai hoan toan kho, n v (g; kg; tan)

aV : la the tch hoan toan ac cua vat lieu, n v (cm 3; m3)

1.1. XAC NH KHOI LNG RIENG CUA XIMANG:1.1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Can ky thuat, o chnh xac 0,1g. Pheu, pipet, ua thuy tinh, gia xuc, giay tham. Bnh Le chatelier. Tu say, bnh hut am. Ximang, dau hoa.

1.1.2: Trnh t th nghiem:
http://thuviendientu.org/http://thuviendientu.org/http://thuviendientu.org/http://thuviendientu.org/


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Ximang c say kho nhiet o 105 - 110oC trong hai gi; sau o,e nguoi trong bnh hut am en nhiet o phong th nghiem. Sang ximang qua sang0,63 e loai bo tap chat va hat ximang a von cuc.

o dau hoa vao bnh Le chatelier ti khi mat thoang cua dau vachso khong (0) (dung pheu thuy tinh e cho dau vao bnh). Dung giay tham het cac

giot dau dnh thanh bnh (pha tren mat thoang). Can 65g ximang a chuan b cac bc tren. Cho 65g ximang t t vao bnh Le chatelier. Sau o, xoay nhe bnh

e khong kh trong ximang thoat het ra ngoai (khong con bot kh xuat hien). Ghi lai v tr mat thoang cua dau trong bnh Le chatelier. The tch

tang them cua dau chnh la the tch ac cua 65g ximang. Khoi lng rieng cua ximang c tnh theo cong thc (1-1):

65a

a a

m

V V (g/cm3)

Ket qua th nghiem xac nh khoi lng rieng cua ximang (chnh xac en

0,1g/cm3) la tr so trung bnh cong cua 2 lan th nghiem, ma ket qua 2 lan th naykhong sai nhau qua 0,02 g/cm3 .

1.2. XAC NH KHOI LNG RIENG CUA CAT:1.2.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Can ky thuat, o chnh xac 0,1g. Bnh khoi lng rieng co vach chuan. Pheu, pipet, ua thuy tinh, gia xuc, giay tham. Tu say, bnh hut am.

Cat, nc.1.2.2: Trnh t th nghiem : Cat c sang qua sang 5mm e loai bo hat ln hn 5mm. Sau o,

cat c ra sach ( e loai bo hat nho hn 0,14mm ), say kho en khoi lngkhong oi nhiet o phong.

Bnh khoi lng rieng c ra sach, say kho. Cho nc vao bnh khoi lng rieng ti khi mc nc en vach

chuan. em can bnh, ghi lai khoi lng m1 (g). o nc trong bnh ra en khi con bnh th dng. Can G = 500g cat a chuan b tren. Cho 500g cat vao bnh khoi lng rieng that cham. Neu lng nc

trong bnh cha ngap het cat th ta them vao cho ngap qua cat. Sau o, lac nhe bnhe khong kh trong cat thoat het ra ngoai (khong con bot kh thoat ra ).

Tiep tuc cho nc vao bnh ti khi mc nc en vach chuan. em can bnh, ghi lai khoi lng m2 (g). o het cat va nc trong bnh ra, ra sach bnh. Khoi lng rieng cua cat cung tuan theo cong thc (1-1). Ta tnh nh

sau:2 1 2 1

500

( ) 500 ( )a

G

G m m m m

(g/cm3)


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Ket qua th nghiem xac nh khoi lng rieng cua cat (chnh xac en 0,1g/cm 3) latr so trung bnh cong cua 2 lan th nghiem, ma ket qua 2 lan th nay khong sainhau qua 0,02 g/cm3.

2. TH NGHIEM XAC NH KHOI LNG THE TCH:Khoi lng the tch cua vat lieu la khoi lng cua mot n v the tch vat lieu tra ng thai t nhien.

Cong thc tnh:

0

0

m

V (2-1)

Trong o:0 : la khoi lng the tch cua vat lieu, n v (g/cm 3; kg/m3; tan/m3)

m: la khoi lng cua vat lieu trang thai t nhien, n v (g; kg; tan)

0V : la the tch trang thai t nhien cua vat lieu, n v (cm 3; m3)

Can chu y rang khoi lng the tch cua vat lieu phu thuoc vao o am ( v khoilng trang thai t nhien phu thuoc vao o am ), do o khi xac nh ai lngnay th phai noi ro la xet o am nao .oi vi vat lieu ri (ximang, cat a ), e xac nh khoi lng the tch, ta se annh trc the tch cua vat lieu bang cach o vat lieu t mot o cao nhat nhxuong 1 thung ong biet trc the tch.oi vi vat lieu co kch thc ro rang va e o (gach at set nung, tam lat nen

men, gach bong ximang ), e xac nh the tch, ta se o kch thc 3 chieu. oivi vat lieu co hnh dang ro rang th can chu y: o rong cua vat lieu gom o rongcau truc va o rong hnh hoc vat the do o khi xac nh khoi lng the tch ma cotnh en the tch rong do dang hnh hoc th o chnh la khoi lng the tch bieukien.

2.1. XAC NH KHOI LNG THE TCH CUA XIMANG:2.1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Can ky thuat, o chnh xac 1g. Lo say, bnh hut am. Thung cha 2,83 lt. Ximang can co cho cac lan th nghiem.

2.1.2: Trnh t th nghiem: em ximang say kho en khoi lng khong oi. Xac nh khoi lng cua thung ong 2.83 lt bang can ky thuat , c

gia tr ( m1 gam ) . Ximang c o vao thung co the tch 2.83 lt thong qua 1 pheu.

Mieng thao cua pheu nam cach mat thung ong la 10 cm.

Dung dao gat t gia sang 2 ben sao cho bang mat thung. em can thung a cha ay ximang, c gia tr (m2 gam).


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Khoi lng the tch cua ximang tuan theo cong thc (2-1). Ta tnhnh sau:

2 1

0

2830

m m

(g/cm3)

2.2. XAC NH KHOI LNG THE TCH CUA CAT:2.2.1: Dung cu, thiet b va nguyen vat lieu can co trong thnghiem: Can ky thuat, o chnh xac 1g. Lo say, bnh hut am. Thung cha 2.83 lt. Cat can co cho cac lan th nghiem.

2.2.2: Trnh t th nghiem: em cat say kho en khoi lng khong oi. Xac nh khoi lng cua thung ong 2.83 lt bang can ky thuat, c

gia tr (m1 gam) . Ximang c o vao thung co the tch 2.83 lt thong qua 1 pheu.

Mieng thao cua pheu nam cach mat thung ong la 10 cm. Dung dao gat t gia sang 2 ben sao cho bang mat thung. em can thung a cha ay cat, c gia tr (m2 gam). Khoi lng the tch cua cat tuan theo cong thc (2-1). Ta tnh nh

sau:2 1

0

2830

m m

(g/cm3)

2.3. XAC NH KHOI LNG THE TCH CUA A:2.3 .1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Can ky thuat, o chnh xac 1g. Can ong ho chnh xac 1g. Thung ong 14.16 lt. a can co cho cac lan th

nghiem.

2.3.2: Trnh t th nghiem: a c phi kho. Xac nh khoi lng cua thung ong 14.16 lt bang can ky thuat,c

gia tr ( m1 gam ) . a c o vao thung co the tch 14.16 lt, o cao ri so vi mieng

thung ong la 10 cm. Dung thc gat t gia sang 2 ben sao cho bang mat thung. em can thung a cha ay a (dung can ong ho), c gia tr (m2

gam). Khoi lng the tch cua cat tuan theo cong thc (2-1). Ta tnh nh

sau: 2 10

14160

m m

(g/cm3)


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2.4. XAC NH KHOI LNG THE TCH CUA GACH AT SET NUNG:2.4.1: Dung cu, thiet b va nguyen vat lieu c an co trong th nghiem: Can ky thuat, o chnh xac 0,1g.

Lo say, bnh hut am. Thc kep va thc gap e o dai.

Gach at set nung can co cho cac lan th nghiem.

2.4.2: Trnh t th nghiem: em gach say ti khoi lng khong oi. Dung can ky thuat e can khoi lng G cua moi vien gach, n v

(g). Dung thc o cac canh cua vien gach. Quy c: canh dai nhat la(a), canh ngan nhat la (c) va canh co chieu dai trung gian la (b). Moi canh o 3 lanva lay gia tr trung bnh cong e lam gia tr tnh toan cua canh o.

1 2 3

3TB

a a aa

(cm)

1 2 3

3TB

b b bb

(cm)

1 2 3

3TB

c c c

c

(cm) Xac nh the tch t nhien cua vien gach ( co tnh o rong hnh hoc )

theo cong thc :0 TB TB TB TBV V a * b *c (cm3)

Xac nh khoi lng the tch bieu kien cua vien gach theo cong thc:

0

a

G

V (g/cm3)

3. TNH TOAN KET QUA: 3.1. Khoi lng rieng:3.1.1. Khoi lng rieng cua ximang:


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m = 65g

V1 = 21ml 165

3.09521

a (g/cm3)

Vay: 3.095a (g/cm3)

3.1.2. Khoi l ng rie ng cua cat: Lan 1: m1 = 592.5g, m2 = 889.5g1

5002,463

500 (889.5 592.5)a

(g/cm3)

Lan 2: m1 = 592.5g, m2 = 890.5g2

5002.475

500 (890.5 592.5)a

(g/cm3)

Vay: 2.463 2.475 2.4692

a

(g/cm3)

3.2. Khoi lng th tch:3.1 .1. Khoi lng the tch cua ximang: Lan 1: m1 = 2560g, m2 = 5800g

01

5800 25601.145

2830

(g/cm3)

Lan 2: m1 = 2560g, m2 = 5856g02

5856 25601.165

2830

(g/cm3)

Vay: 0 1.145 1.165 1.1552

(g/cm3)

3.1.2. Khoi lng the t ch cua cat: Lan 1: m1 = 2560g, m2 = 6900g

01

6900 25601.534

2830

(g/cm3)

Lan 2: m1 = 2560g, m2 = 6930g02

6930 25601.544

2830

(g/cm3)

Vay: 0 1.534 1.544 1.5392

(g/cm3)

3.1.3. Khoi lng the tch cua a : Lan 1: m1 = 9000g, m2 = 28700g

01

28700 90001.391

14160

(g/cm3)

Lan 2: m1 = 9000g, m2 = 29500g02

29500 90001.448

14160

(g/cm3)

Ln 3: m1 = 9000g ,m2 = 29200 ( g/cm3)03

29200 90001.427

14160


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Vay: 0 1.391 1.448 1.427 1.4223

(g/cm3)

3.1.4. Khoi lng the tch cua at set nung:

Mu L(cm) a b d1 d2 m V V2l1 17.7 7.63 7.6 2.2 2.41 1090 1032 160.5 1.056 1.2522 17.75 7.65 7.6 2.2 2.4 1091 1031 160.4 1.058 1.2483 17.8 7.66 7.6 2.21 2.4 1090 1031 160.7 1.054 1.250

Vgch=abl 0g 3mg

(g/cm )Vg

Vl=d2l/4 0g 32l

m' (g / cm )

Vg V

0g31.056 1.058 1.054 1.056(g / cm )

3

0g31.252 1.248 1.25' 1, 25(g / cm )

3

4. NHAN XET:Kt qu th nghim c s sai s so vi l thuyt. Nguyn nhn y l do:Thao tc th nghim cha gn gng, cn ximng dnh trn c bnh Lechatelier,bt

kh cha bay ra ht.Sai s khi cn ximng.Ximng trong phng th nghim c th b ht m.


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HNH ANH MOT SO DUNG CU TH NGHIEM

CAN K THUAT CO O CHNH XAC 0,1 GAM

CAN K THUAT CO O CHNH XAC 1 GAM


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BNH LSATLIE THUNG CHA COTHE TCH 14,16 LT

MUONG XUC BAY


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BAI 2 :XAC NH LNG NC TIEU CHUAN CUA XIMANG VA

MAC XIMANG

MU C CH TH NGHIEM: Lam quen vi phng phap va thao tac th nghiem xac nh hai ai lng

lng nc tieu chuan cua ximang va mac ximang. T ho ximang co o deo tieu chuan, ta co the xac nh c thi gian ninh

ket cua ximang va t o a ra thi gian thi cong hp l cho ximang va hon hp betongv..v. Ngoai ra, t lng nc tieu chuan, ta co the xac nh lng nc ng vi luc honhp betong co o lu ong tot nhat ma khong b phan tang.

Xac nh mac ximang tc la xac nh mot ai lng can phai co e tnhtoan cap phoi betong.

Lng nc tieu chuan la ch tieu quan trong e anh gia ximang.1. TH NGHIEM LNG NC TIEU CHUAN CUA XIMANG:

Lng nc tieu chuan cua ximang la lng nc am bao che tao ho ximang ato deo tieu chuan. Lng nc tieu chuan cua ximang c tnh bang % so vilng ximang.o deo tieu chuan c xac nh bang dung cu Vica, vi kim vica ng knh = 10

mm. Cho kim ri t o cao H = 0 mm so vi mat ho ximang, neu ho ximang ambao o cam sau cua kim Vica t 33 35 mm th ho ximang o co o deo tieuchuan va lng nc ng vi o deo o chnh la lng nc tieu chuan.

1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Dung cu Vica. Can ky thuat o chnh xac 0,1g. Khau hnh con bang nha. Chao hnh chom cau va bay (khi tron tay) hoac may tron.

Ong ong hnh tru loai 150 ml, pipet, khan lau t.

1.2: Trnh t th nghiem: Can 400g ximang a qua sang 0.63 mm. ong lng nc bang 27% hoac 29% so vi lng ximang.


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Neu tron tay th:Cho lng ximang nay vao chao tron a lau am, dung bay moi

thanh hoc gia, o lng nc vao, sau 30 giay bat au tron theo kieudan manh va giat lui, thi gian tron khoang 5 phut. Neu tron may th:

Lau am noi tron, canh tron cua may.Ta cho nc vao noi tron trc; sau o, ta cho ximang vao noi tron.

Lap canh tron vao may, cho may tron toc o thap trong 60giay, dng may.

Dung bay vet sach ho ximang dnh canh tron va thanh noi trongkhoang thi gian 30 giay.

Tiep tuc cho may tron toc o cao trong 120 giay. Tron xong, dung bay cho ho ximang vao khau hnh con va cho motlan, ep sat vanh khau xuong mat tam micca roi dap tam mica len matban 5 6 cai. Dung bay a lau am gat cho ho ximang bang mieng khau. at khau vao dung cu Vica. Ha cho au kim Vica ta tren miengvanh khau, khoa chat kim Vica; ieu chnh kim chia vach ve so 40 (thang chia ben phai cua dung cu ) ( hoac 10 neu la thang chia ben trai ),khoa chat kim chia vach; di chuyen tam mica sao cho kim vica giavanh khau. M vt cho kim vica t do cam vao ho ximang. Sau 30 giay, ta co nh kim va oc gia tr. Neu au kim cam cachay 5 7 mm th at. Neu khong at th phai tron me khac vi lngnc nhieu hn hoac t hn 0.5%.

2. TH NGHIEM XAC NH MAC CUA XIMANG:Mac ximang c xac nh da theo:Cng o chu uon cua 3 mau va ximang tieu chuan.Cng o chu nen cua 6 na mau tao thanh t 3 mau va noi en.3 mau ban au dung xac nh cng o chu uon phai thoa yeu cau sau:

Kch thc mau th 4x4x16 cm. Va ximang la hon hp ximang cat theo ty le 1:3. Ty le N/X la

1/2. Mau va sau khi uc xong phai c dng ho 1 ngay trong moi

trng khong kh am cua phong th nghiem va 27 ngay trong moi trng nc co nhiet

o thng.

2.1: D ung cu, thiet b va nguyen vat lieuca n co trong th nghiem: Khuon uc mau kch thc

4x4x16 cm. Chay am co kch thc mat

ay 3,5x3,5 cm. Can ky thuat o chnh xac

0.1g; ong ong thuy tinh 500 ml, pipet. Chao hnh chom cau va bay(khi tron tay) hoac may tron.


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May uon va ep mau, tam em ep. Ximang, cat tieu chuan, nc sach.

2.2: Trnh t th nghiem: Lap rap khuon va lau dau khuon 4x4x16 cm, lap nap noi pha tren

vao khuon. Can lng ximang X = 450 g va cat C = 1350 g ( am bao ty le X/C 1/3 ). Cat dung ay la cat tieu chuan ( c hat t 0,5 1 mm ).

Ty le N/X = 0,5 N = 225 g. Neu tron tay th:

Cho lng ximang va cat vao chao roi tron eu, chao a c lausach bang vai am. Sau 1 phut, ta dung bay moi thanh hoc gia, cholng nc tren vao, tiep tuc tron eu. Neu tron may th :

Lau am noi tron, canh tron cua may. Ta cho nc vao noi tron trc; sau o, ta cho ximang vao noi

tron.Lap canh tron vao may, cho may tron toc o thap trong 30 giay;

dng may.Dung bay vet sach va ximang dnh canh tron va thanh noi trong

khoang thi gian 30 giay. Tiep tuc cho may tron toc o cao trong 120 giay.

Hon hp va tron xong cho vao moi mau trong khuon theo 2 lan,lan 1 cho va vao khoang hn chieu cao cua khuon, am 20 chay qua lai doc

theo chieu dai khuon ( 2 lt i va 2 lt ve, moi lt la 5 chay ). Lan 2 tiep tuccho va vao ay khuon va cung am qua lai 20 chay. Phai am bang 2 tay. Dan moi au khuon 5 cai, dung bay a lau am miet cho nhan mat

va. Dng ho mau 1 ngay trong khuon sau o lay ra ngam nc 27

ngay. Sau khi dng ho 28 ngay, lay mau ra lau rao mat va th cng o

ngay, khong e cham qua 10 phut. Tien hanh th nghiem uon mau, moi mau th b gay thanh 2 na.Sau o tien hanh th nghiem xac nh cng o chu nen vi 6 na

mau tng ng. Gia tr cng o chu uon c tnh toan :

3

.3.

2u

uF L

Rb

(kg/cm2)

uF : ti trng max lc mu b ph hoi

L : Khong cch gia 2 gi

b : b rng mu xi mng

Gia tr cng o chu nen c tnh toan :n

PR F (kg/cm

2

)P la lc nen pha hoai ng vi moi na mau (kg)


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F = 16 cm2 : tiet dien chu lc cua moi na mau. Mac ximang la tr so trung bnh cua 4 ket qua gan nhau nhat trong 6

ket qua nen c.4

1

4

i

n TB

i

R

R R

(kg/cm2)

3. T NH TOAN KET QUA :Lng nc tiu chun: 29%Khi lng nc: 146gKim vica cch y: 7mmCng o chu uon cua ximang:

Mu b(cm) L(cm) Fu(kg) Ru(kg/ cm2)1 4 10 291 68.22 4 10 271.5 63.6

3 4 10 240.5 56.4Cng o chu uon trung bnh: Ru = 62.7(kg/cm2)

Cng o chu nen cua ximang:Mu A( cm2) Fu (kg) Rn (kg/ cm2) Sai s Ghi chu

1 16 4900 306.3 11.8 Loi2 16 2660 166.3 62.5 Loai3 16 2930 182.95 47.4 Loi

4 16 3470 216.65 24.7 Loi5 16 3590 224.4 20.4 Loi6 16 4080 254.8 6.1 Nhn

5 mu u co sai so >10% nen loai.

4. NHAN XET:Lng nc tieu chuan cua ximang phu thuoc thanh phan khoang vat va omn cua no.

Ximang khi b nen th be ra ch khong theo nhng goc 450 v mc o ket dnhcua ximang va cat kem.Can chu y khac phuc nhng nguyen nhan sai sot khi uc mau e nang cao chatlng mau.

BAI 3:PHAN TCH THANH PHAN HAT CUA COT LIEU DUNG CHO

TNH TOAN CAP PHOI BETONG


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MU C CH TH NGHIEM: Lam quen vi phng phap va thao tac th nghiem xac nh ng cap phoi

hat cua a dam va cat vang; xac nh Dmax cua a; xac nh moul o ln cua cat. So sanh ng cap phoi hat a ve c t thc nghiem vi vung cap phoi

hat cho phep ( cua tieu chuan ); t o; ta ket luan loai a va cat o co thch hp vi viec

che tao betong hay khong. Xac nh ng cap phoi hat, Dmax cua a, moul o ln cua cat cho phepchung ta d oan mc o chat st cua hon hp betong, lng dung ximang, lng dungnc cho hon hp betong v..v.1. TH NGHIEM XAC NH THANH PHAN HAT CUA A DAM:1.1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem:

Bo ray sang tieu chuan co ng knh mat sang nh sau:32 25 20 15 - 12.5 10 5 mm

Can ky thuat o chnh xac 1 g. Ro ng a, gia xuc a. a dam kho.

1.1.2: Trnh t th nghiem : Can G = 15 kg a dam. em 15 kg a dam sang qua bo sang tieu chuan

va ke tren. Can lng a sot tren moi sang, ky hieu G i ( i =32; 25; 20; 12,5; 10;

5 ).

Tnh lng sot rieng biet tren moi sang, theo cong thc :*100%

i

i

Ga

G

Tnh lng sot tch luy tren sang i ( i =32; 25; 20; 12,5; 10; 5 )theocong thc:

32 25 ...i i A a a a Xac nh Dmax cua a va Dmin cua a (Dmax la ng knh mat sang

cua sang co lng sot tch luy nho hn va gan 10% nhat; Dmin la ng knh matsang cua sang co lng sot tch luy ln hn va gan 90% nhat).

Ve ng cap phoi hat cua a dam t so lieu thc nghiem. So sanhng cap phoi hat t thc nghiem vi vung cap phoi hat cho phep cua tieu chuan.

Vung cap phoi hat cho phep cua a dam dung cho betong la :Dmin 0,5(Dmax + Dmin ) Dmax 1,25Dmax

Lng sot tch luy Ai (%) 90 - 100 40 - 70 0 - 10 0

2. TH NGHIEM XAC NH THANH PHAN HAT CUA CAT:2.1: D ung cu, thiet b va nguyen vat lieu can co trong th nghiem: Bo ray sang tieu chuan co ng knh mat sang nh sau:


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5 2.5 1.25 0.63 0.315 0.16 mm Can ky thuat o chnh xac 0,1g. Ro ng a, gia xuc cat. Cat vang a ra sach va say kho.2.2: Trnh t th nghiem:

em cat sang qua sang 5 mm. Can G = 1000 g cat va sang qua sang 5 mm. em 1000 g cat sang qua bo sang tieu chuan va ke tren. Can lng a sot tren moi sang, ky hieu G i (i =5; 2,5; 1,25; 0,63;

0,315; 0,16). Tnh lng sot rieng biet tren moi sang, theo cong thc:

*100%i

i

Ga

G

Tnh lng sot tch luy tren sang i (i =5; 2,5; 1,25; 0,63; 0,315; 0,16)theo cong thc:

5 2, 5 ...i i A a a a Ve ng cap phoi hat cua cat vang t so lieu thc nghiem. So sanh

ng cap phoi hat t thc nghiem vi vung cap phoi hat cho phep cua tieu chuan.

Vung cap phoi hat cho phep cua cat vang dung cho betong la:di (mm) 5 2,5 1,25 0,63 0,315 0,16Ai (%) 0 0 - 20 15 45 35 70 70 90 90 - 100

Tnh mo ul o ln cua cat theo cong thc:2, 5 1, 25 0, 63 0, 315 0, 16

100dl

A A A A AM

Theo moul o ln, ta chia cat lam 4 nhom:2,5 dlM 3,3 cat hat to2,0 dlM 2,5 cat hat va1,0 dlM 2,0 cat hat nho0,7 dlM 1,0 cat hat rat nho

3. TNH TOAN KET QUA3.1: Xac nh thanh phan hat cua a:

C sang(mm)

Lng sot riengbiet (kg)

% lng sotrieng biet

Lng sot tchluy (kg)

% lng sot tchluy

32 950 6.4 950 6.425 5000 33.5 5950 4020 5700 38.2 11650 78.1

12,5 2800 18.8 14450 96.9

10 350 2.3 14800 99.35 60 0.4 14860 99.7

ay sang 50 0.3 14910 100


16/23


14910Sai s th nghim:

15 14,910% 100% 0, 6% 1%

15x

Dmax = 32 mm

Dmin = 12,5 mm12

(Dmax +Dmin)= 22,25 mm

1,25Dmax = 40 mm

NG BIEU DIEN CAP PHOI HAT CUA A

0

10

20

30

40

50

60

70

80

90

100

Lng sot tch luy(%)

12.5 20 22.5 32 40

Kch thc losang(mm)


17/23


3.2: Xac nh thanh phan hat cua cat:C sang (mm)

Lng sotrieng biet (g)

% lng sotrieng biet

Lng sot tchluy (g)

% lng sottch luy

5 0 0 0 0

2,5 3.4 0.34 3.4 0.34

1,25 90.6 9.06 94 9.4

0,63 345.4 34.54 439.4 43.94

0,315 351.5 35.15 790.9 79.09

0,16 183.4 18.34 974.3 97.43

ay sang 18 1.8 992.3 99.23

992.3

Sai s th nghim:1000 992.3

% 100% 0.77% 1%1000

x

Moul o ln:0.34 9.4 43.94 79.09 97.43

2.302100

M


18/23


NG BIEU DIEN CAP PHOI HAT CUA CAT

0

10

20

30

40

50

60

70

80

90

100

0 0.16 0.315 0.63 0.125 2.5 5

Kch thc lo

sang(mm)

Lng sot tch luy(%)


19/23


4. NHAN XET :Thanh phan cap phoi hat cua a:

ng bieu dien cap phoi hat cua a hoang toan nam trong pham vicho phep do o loai a em th nghiem c dung lam cot lieu cho betong.Thanh phan cap phoi hat cua cat:

Ket qua th nghiem cho moul o ln: Mdl =2.302[2;2,4] nen cat emth nghiem la cat hat va.

ng bieu dien cap phoi hat cua cat co phan nam ngoai pham vi chophep nen loai cat em th nghiem khong c dung lam cot lieu cho betong.

BAI 4:XAC NH O LU ONG CUA HON HP BETONG

MU C CH TH NGHIEM: Lam quen vi phng phap va thao tac th nghiem xac nh o lu ong cua

hon hp betong deo thong thng. T thc nghiem, chung ta a ra nhan xet ve tnh cong tac cua hon hp

betong, kha nang lap ay khuon cua hon hp betong di tac ong cua am

len, so sanh vi o lu ong thiet ke ban au.1. TH NGHIEM XAC NH O LU ONG CUA HON HP BETONG:

o lu ong cua hon hp betong la ch tieu quan trong cua hon hp betong,o lu ong cua hon hp betong anh gia kha nang de chay cua hon hp betong di tacdung cua trong lng ban than hoac gia cong chan ong.

o lu ong cua hon hp betong c anh gia thong qua o sut non hoacla o cng cua hon hp betong. oi vi hon hp betong deo thong thng th o lu ongc anh gia thong qua o sut non.

1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem: Con th o

sut hnh non cut, kchthc: chieu cao h = 300mm, ng knh aydi D = 200 mm, ngknh ay tren d = 100mm, con non cut nayc ap dung oi vi c

hat ln nhat cua cot lieuti 40 mm. Que am bang sat tron trn 16 dai 600 mm.


20/23


Pheu o hon hp betong. Thc la bang kim loai o chnh xac 1 mm. Khay tron vat lieu, bay, tam kim loai nhan. Ong thuy tinh dung ong nc, can ky thuat co o chnh xac 1 g. Ximang, cat, a tra ng thai kho hoan toan, nc sach can cho nhao

tron hon hp betong.1.2: Trnh t th nghiem: S dung ximang PCB40. Gia s cap phoi cua hon hp betong M200, SN = 3 8 cm nh sau :

o Ximang = 293 kg/m3betongo Cat = 653 kg/m3betongo a = 1228 kg/m3betongo Nc = 195 kg/m3betong

T cap phoi cua 1m3 betong, ta tnh quy oi cho viec che tao 12 ltbetong ( v th o sut non th can 8 lt, uc mau betong trong khuon150*150*150 th can t nhat la 10,2 lt ) :

o Ximang = 3,516 kg/12litbetongo Cat = 7,836 kg/12litbetongo a = 14,736 kg/12litbetongo Nc = 2,34 kg/12litbetong

Nhao tron hon hp betong. Non cut tieu chuan c lau am, at thang ng tren nen phang +

cng + khong tham nc.

Gi va ep chat non cut tieu chuan xuong nen phang; o betong vaonon cut thong qua pheu; betong c o vao non cut thanh 3 lp; moi lp cam 25 cai bang que am tieu chuan, am t ngoai vao trong, que am phai songsong ng sinh cua non cut; ke t lp betong th hai, que am khong c ansau xuong lp betong pha di qua 2 cm.

am xong, dung bay xoa phang mat cua non cut, thu don betong rivai chan non cut. T t nhat non cut ra ( trong vong 5 7 giay ).

at non cut tieu chuan sat ben khoi hon hp betong, at que amlen non cut, dung thc o khoang cach t mep di que am ti nh cao nhatcua khoi hon hp betong. Ghi la i o sut o c va so sanh vi o sut thiet ke.

- Neu SN > 8 th hon hp betong nhao phai tang lng cat va a saocho C/ = const. Neu SN < 3 th hon hp betong cng phai tang lng ncva ximang sao cho N/X = const.

- Neu khi rut con ma khoi mau betong b o th phai th lai bangmau khac.


21/23


TRNH T TH O SUT

2. TNH TOAN KET QUA:Lng ximang: 3.5kg, cat: 7.8kg ,a: 14.8kg, nc: 2.4 lt.o sut ta o c trong th nghiem la 8cm.

3. NHAN XET :- o sut nam trong khoang cho phep 6 8cm, Khong can tien hanh lai th nghiem ma

tien hanh uc mau lien. BAI 5:UC MAU BETONG E XAC NH MAC A BETONG

MU C CH TH NGHIEM: Lam quen vi phng phap va thao tac th nghiem trong viec uc maubetong e xac nh mac cua a betong.

T so lieu nen pha hoai mau th tren thc te, chung ta a ra nhan xet veo ben nen so vi thiet ke la at hay khong at, anh gia s bo o ben cuacong trnh hoac cau kien lam t hon hp betong ma ta uc th.

1. TH NGHIEM UC MAU BETONG E XAC NH MAC CUA A BETONG- Mac cua a bt la cng o nen pha hoai (lay gia tr trung bnh) cua 1 to mau th tieu

chuan. To mau th tieu chuan la to mau th nh sau:

To gom 3 mau lap phng, kch thc 1 mau la 150x150x150. To mau c che tao va dng ho trong ieu kien chuan. Ngha la: sau khi uc

xong th dng ho mot ngay trong khuon vi t = 27 2 0C va W > 95%; sau 1 ngay,ta thao khuon va ngam ngap cac mau trong nc vi t = 27 2 0C.

- Trong mot so trng hp, neu khong s dung khuon co kch thc 150x150x150 thcan phai nhan gia tr nen thc te vi he so quy oi. V du nh sau:

HNH DANG VA KCH THC MAU (mm) HE SO TNH OIMau lap phng: 100 x100 x100 0,91Mau lap phng: 150 x150 x150 1,00Mau lap phng: 200 x 200 x200 1,05Mau lap phng: 300 x300 x300 1,10Mau lap phng: 71,4 x 143 1,16Mau lap phng: 100 x 200 1,16Mau lap phng: 150 x 300 1,20Mau lap phng: 200 x 400 1,24


22/23


1.1: Dung cu, thiet b va nguyen vat lieu can co trong th nghiem :Trong th nghiem nay chung ta s dung honhp bt va mi th o sut ( bai 4 ) euc mau. Bo khuon thep 3 ngan, mot ngan co kch

thc 150x150x150. Bua cao su, bay. Que am bang sat tron16 dai 600 mm. Be dng ho. May nen mau, va mot so dung cu khac.

1.2: Trnh t th nghiem : Khuon c lam ve sinh sach, rap khuon, bo mot lp dau mong mac

trong khuon. Cho hon hp bt ( a th o sut ) vao moi ngan lam 2 lp. Moi lp, ta

dung que am am 25 cai eu tren toan bo dien tch mat khuon, am tngoai vao trong.

Dung bua go nhe xung quanh thanh khuon cho ti khi nc ximangchay, noi len tren mat, dankhuon 6 cai, dung bay xoa bangkhuon.

Ghi + dan nhan ( hang muc, kyhieu mau, ngay u, mac, ngiuc ) va em dng ho. Sau khidng ho 1 ngay trong khuon,lay mau ra ngam trong nc 27ngay.

em mau bt a dng ho ungay i nen. Cng o chu nencua tng mau c tnh theocong thc :

(28 )n

P

R ngay F (kg/cm

2

) la he so tnh o phu thuoc vao hnh dang mau thP la lc nen pha hoai mau, kgfF la dien tch mat chu lc = 225 cm2

Ket qua th nghiem xac nh cng o nen cua bt lay bang tr so trungbnh cong t 3 gia tr cng o cua 3 mau th. Can xem xet ieu kiensau: 0,85RTB


23/23

(cm2) (kg/cm2)

1 14,814,4 14,814,5 213,86 417,14 195.1

2 14,414,6 14,514,55 210,61 443,04 210.4

3 14,714,9 14,814,9 219,78 394,62 197.6

R1

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